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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/misc/eeprom
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/misc/eeprom')
-rw-r--r--drivers/misc/eeprom/Kconfig134
-rw-r--r--drivers/misc/eeprom/Makefile10
-rw-r--r--drivers/misc/eeprom/at24.c861
-rw-r--r--drivers/misc/eeprom/at25.c536
-rw-r--r--drivers/misc/eeprom/digsy_mtc_eeprom.c103
-rw-r--r--drivers/misc/eeprom/ee1004.c245
-rw-r--r--drivers/misc/eeprom/eeprom.c215
-rw-r--r--drivers/misc/eeprom/eeprom_93cx6.c372
-rw-r--r--drivers/misc/eeprom/eeprom_93xx46.c583
-rw-r--r--drivers/misc/eeprom/idt_89hpesx.c1597
-rw-r--r--drivers/misc/eeprom/max6875.c205
11 files changed, 4861 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
new file mode 100644
index 000000000..2d240bfa8
--- /dev/null
+++ b/drivers/misc/eeprom/Kconfig
@@ -0,0 +1,134 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "EEPROM support"
+
+config EEPROM_AT24
+ tristate "I2C EEPROMs / RAMs / ROMs from most vendors"
+ depends on I2C && SYSFS
+ select NVMEM
+ select NVMEM_SYSFS
+ select REGMAP
+ select REGMAP_I2C
+ help
+ Enable this driver to get read/write support to most I2C EEPROMs
+ and compatible devices like FRAMs, SRAMs, ROMs etc. After you
+ configure the driver to know about each chip on your target
+ board. Use these generic chip names, instead of vendor-specific
+ ones like at24c64, 24lc02 or fm24c04:
+
+ 24c00, 24c01, 24c02, spd (readonly 24c02), 24c04, 24c08,
+ 24c16, 24c32, 24c64, 24c128, 24c256, 24c512, 24c1024, 24c2048
+
+ Unless you like data loss puzzles, always be sure that any chip
+ you configure as a 24c32 (32 kbit) or larger is NOT really a
+ 24c16 (16 kbit) or smaller, and vice versa. Marking the chip
+ as read-only won't help recover from this. Also, if your chip
+ has any software write-protect mechanism you may want to review the
+ code to make sure this driver won't turn it on by accident.
+
+ If you use this with an SMBus adapter instead of an I2C adapter,
+ full functionality is not available. Only smaller devices are
+ supported (24c16 and below, max 4 kByte).
+
+ This driver can also be built as a module. If so, the module
+ will be called at24.
+
+config EEPROM_AT25
+ tristate "SPI EEPROMs (FRAMs) from most vendors"
+ depends on SPI && SYSFS
+ select NVMEM
+ select NVMEM_SYSFS
+ help
+ Enable this driver to get read/write support to most SPI EEPROMs
+ and Cypress FRAMs,
+ after you configure the board init code to know about each eeprom
+ on your target board.
+
+ This driver can also be built as a module. If so, the module
+ will be called at25.
+
+config EEPROM_LEGACY
+ tristate "Old I2C EEPROM reader (DEPRECATED)"
+ depends on I2C && SYSFS
+ help
+ If you say yes here you get read-only access to the EEPROM data
+ available on modern memory DIMMs and Sony Vaio laptops via I2C. Such
+ EEPROMs could theoretically be available on other devices as well.
+
+ This driver is deprecated and will be removed soon, please use the
+ better at24 driver instead.
+
+ This driver can also be built as a module. If so, the module
+ will be called eeprom.
+
+config EEPROM_MAX6875
+ tristate "Maxim MAX6874/5 power supply supervisor"
+ depends on I2C
+ help
+ If you say yes here you get read-only support for the user EEPROM of
+ the Maxim MAX6874/5 EEPROM-programmable, quad power-supply
+ sequencer/supervisor.
+
+ All other features of this chip should be accessed via i2c-dev.
+
+ This driver can also be built as a module. If so, the module
+ will be called max6875.
+
+
+config EEPROM_93CX6
+ tristate "EEPROM 93CX6 support"
+ help
+ This is a driver for the EEPROM chipsets 93c46 and 93c66.
+ The driver supports both read as well as write commands.
+
+ If unsure, say N.
+
+config EEPROM_93XX46
+ tristate "Microwire EEPROM 93XX46 support"
+ depends on SPI && SYSFS
+ select REGMAP
+ select NVMEM
+ select NVMEM_SYSFS
+ help
+ Driver for the microwire EEPROM chipsets 93xx46x. The driver
+ supports both read and write commands and also the command to
+ erase the whole EEPROM.
+
+ This driver can also be built as a module. If so, the module
+ will be called eeprom_93xx46.
+
+ If unsure, say N.
+
+config EEPROM_DIGSY_MTC_CFG
+ bool "DigsyMTC display configuration EEPROMs device"
+ depends on GPIO_MPC5200 && SPI_GPIO
+ help
+ This option enables access to display configuration EEPROMs
+ on digsy_mtc board. You have to additionally select Microwire
+ EEPROM 93XX46 driver. sysfs entries will be created for that
+ EEPROM allowing to read/write the configuration data or to
+ erase the whole EEPROM.
+
+ If unsure, say N.
+
+config EEPROM_IDT_89HPESX
+ tristate "IDT 89HPESx PCIe-swtiches EEPROM / CSR support"
+ depends on I2C && SYSFS
+ help
+ Enable this driver to get read/write access to EEPROM / CSRs
+ over IDT PCIe-swtich i2c-slave interface.
+
+ This driver can also be built as a module. If so, the module
+ will be called idt_89hpesx.
+
+config EEPROM_EE1004
+ tristate "SPD EEPROMs on DDR4 memory modules"
+ depends on I2C && SYSFS
+ help
+ Enable this driver to get read support to SPD EEPROMs following
+ the JEDEC EE1004 standard. These are typically found on DDR4
+ SDRAM memory modules.
+
+ This driver can also be built as a module. If so, the module
+ will be called ee1004.
+
+endmenu
diff --git a/drivers/misc/eeprom/Makefile b/drivers/misc/eeprom/Makefile
new file mode 100644
index 000000000..a9b4b6579
--- /dev/null
+++ b/drivers/misc/eeprom/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_EEPROM_AT24) += at24.o
+obj-$(CONFIG_EEPROM_AT25) += at25.o
+obj-$(CONFIG_EEPROM_LEGACY) += eeprom.o
+obj-$(CONFIG_EEPROM_MAX6875) += max6875.o
+obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o
+obj-$(CONFIG_EEPROM_93XX46) += eeprom_93xx46.o
+obj-$(CONFIG_EEPROM_DIGSY_MTC_CFG) += digsy_mtc_eeprom.o
+obj-$(CONFIG_EEPROM_IDT_89HPESX) += idt_89hpesx.o
+obj-$(CONFIG_EEPROM_EE1004) += ee1004.o
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
new file mode 100644
index 000000000..938c4f41b
--- /dev/null
+++ b/drivers/misc/eeprom/at24.c
@@ -0,0 +1,861 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * at24.c - handle most I2C EEPROMs
+ *
+ * Copyright (C) 2005-2007 David Brownell
+ * Copyright (C) 2008 Wolfram Sang, Pengutronix
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitops.h>
+#include <linux/capability.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+/* Address pointer is 16 bit. */
+#define AT24_FLAG_ADDR16 BIT(7)
+/* sysfs-entry will be read-only. */
+#define AT24_FLAG_READONLY BIT(6)
+/* sysfs-entry will be world-readable. */
+#define AT24_FLAG_IRUGO BIT(5)
+/* Take always 8 addresses (24c00). */
+#define AT24_FLAG_TAKE8ADDR BIT(4)
+/* Factory-programmed serial number. */
+#define AT24_FLAG_SERIAL BIT(3)
+/* Factory-programmed mac address. */
+#define AT24_FLAG_MAC BIT(2)
+/* Does not auto-rollover reads to the next slave address. */
+#define AT24_FLAG_NO_RDROL BIT(1)
+
+/*
+ * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable.
+ * Differences between different vendor product lines (like Atmel AT24C or
+ * MicroChip 24LC, etc) won't much matter for typical read/write access.
+ * There are also I2C RAM chips, likewise interchangeable. One example
+ * would be the PCF8570, which acts like a 24c02 EEPROM (256 bytes).
+ *
+ * However, misconfiguration can lose data. "Set 16-bit memory address"
+ * to a part with 8-bit addressing will overwrite data. Writing with too
+ * big a page size also loses data. And it's not safe to assume that the
+ * conventional addresses 0x50..0x57 only hold eeproms; a PCF8563 RTC
+ * uses 0x51, for just one example.
+ *
+ * Accordingly, explicit board-specific configuration data should be used
+ * in almost all cases. (One partial exception is an SMBus used to access
+ * "SPD" data for DRAM sticks. Those only use 24c02 EEPROMs.)
+ *
+ * So this driver uses "new style" I2C driver binding, expecting to be
+ * told what devices exist. That may be in arch/X/mach-Y/board-Z.c or
+ * similar kernel-resident tables; or, configuration data coming from
+ * a bootloader.
+ *
+ * Other than binding model, current differences from "eeprom" driver are
+ * that this one handles write access and isn't restricted to 24c02 devices.
+ * It also handles larger devices (32 kbit and up) with two-byte addresses,
+ * which won't work on pure SMBus systems.
+ */
+
+struct at24_data {
+ /*
+ * Lock protects against activities from other Linux tasks,
+ * but not from changes by other I2C masters.
+ */
+ struct mutex lock;
+
+ unsigned int write_max;
+ unsigned int num_addresses;
+ unsigned int offset_adj;
+
+ u32 byte_len;
+ u16 page_size;
+ u8 flags;
+
+ struct nvmem_device *nvmem;
+ struct regulator *vcc_reg;
+ void (*read_post)(unsigned int off, char *buf, size_t count);
+
+ /*
+ * Some chips tie up multiple I2C addresses; dummy devices reserve
+ * them for us.
+ */
+ u8 bank_addr_shift;
+ struct regmap *client_regmaps[];
+};
+
+/*
+ * This parameter is to help this driver avoid blocking other drivers out
+ * of I2C for potentially troublesome amounts of time. With a 100 kHz I2C
+ * clock, one 256 byte read takes about 1/43 second which is excessive;
+ * but the 1/170 second it takes at 400 kHz may be quite reasonable; and
+ * at 1 MHz (Fm+) a 1/430 second delay could easily be invisible.
+ *
+ * This value is forced to be a power of two so that writes align on pages.
+ */
+static unsigned int at24_io_limit = 128;
+module_param_named(io_limit, at24_io_limit, uint, 0);
+MODULE_PARM_DESC(at24_io_limit, "Maximum bytes per I/O (default 128)");
+
+/*
+ * Specs often allow 5 msec for a page write, sometimes 20 msec;
+ * it's important to recover from write timeouts.
+ */
+static unsigned int at24_write_timeout = 25;
+module_param_named(write_timeout, at24_write_timeout, uint, 0);
+MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
+
+struct at24_chip_data {
+ u32 byte_len;
+ u8 flags;
+ u8 bank_addr_shift;
+ void (*read_post)(unsigned int off, char *buf, size_t count);
+};
+
+#define AT24_CHIP_DATA(_name, _len, _flags) \
+ static const struct at24_chip_data _name = { \
+ .byte_len = _len, .flags = _flags, \
+ }
+
+#define AT24_CHIP_DATA_CB(_name, _len, _flags, _read_post) \
+ static const struct at24_chip_data _name = { \
+ .byte_len = _len, .flags = _flags, \
+ .read_post = _read_post, \
+ }
+
+#define AT24_CHIP_DATA_BS(_name, _len, _flags, _bank_addr_shift) \
+ static const struct at24_chip_data _name = { \
+ .byte_len = _len, .flags = _flags, \
+ .bank_addr_shift = _bank_addr_shift \
+ }
+
+static void at24_read_post_vaio(unsigned int off, char *buf, size_t count)
+{
+ int i;
+
+ if (capable(CAP_SYS_ADMIN))
+ return;
+
+ /*
+ * Hide VAIO private settings to regular users:
+ * - BIOS passwords: bytes 0x00 to 0x0f
+ * - UUID: bytes 0x10 to 0x1f
+ * - Serial number: 0xc0 to 0xdf
+ */
+ for (i = 0; i < count; i++) {
+ if ((off + i <= 0x1f) ||
+ (off + i >= 0xc0 && off + i <= 0xdf))
+ buf[i] = 0;
+ }
+}
+
+/* needs 8 addresses as A0-A2 are ignored */
+AT24_CHIP_DATA(at24_data_24c00, 128 / 8, AT24_FLAG_TAKE8ADDR);
+/* old variants can't be handled with this generic entry! */
+AT24_CHIP_DATA(at24_data_24c01, 1024 / 8, 0);
+AT24_CHIP_DATA(at24_data_24cs01, 16,
+ AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24c02, 2048 / 8, 0);
+AT24_CHIP_DATA(at24_data_24cs02, 16,
+ AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24mac402, 48 / 8,
+ AT24_FLAG_MAC | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24mac602, 64 / 8,
+ AT24_FLAG_MAC | AT24_FLAG_READONLY);
+/* spd is a 24c02 in memory DIMMs */
+AT24_CHIP_DATA(at24_data_spd, 2048 / 8,
+ AT24_FLAG_READONLY | AT24_FLAG_IRUGO);
+/* 24c02_vaio is a 24c02 on some Sony laptops */
+AT24_CHIP_DATA_CB(at24_data_24c02_vaio, 2048 / 8,
+ AT24_FLAG_READONLY | AT24_FLAG_IRUGO,
+ at24_read_post_vaio);
+AT24_CHIP_DATA(at24_data_24c04, 4096 / 8, 0);
+AT24_CHIP_DATA(at24_data_24cs04, 16,
+ AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+/* 24rf08 quirk is handled at i2c-core */
+AT24_CHIP_DATA(at24_data_24c08, 8192 / 8, 0);
+AT24_CHIP_DATA(at24_data_24cs08, 16,
+ AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24c16, 16384 / 8, 0);
+AT24_CHIP_DATA(at24_data_24cs16, 16,
+ AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24c32, 32768 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA(at24_data_24cs32, 16,
+ AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24c64, 65536 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA(at24_data_24cs64, 16,
+ AT24_FLAG_ADDR16 | AT24_FLAG_SERIAL | AT24_FLAG_READONLY);
+AT24_CHIP_DATA(at24_data_24c128, 131072 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA(at24_data_24c256, 262144 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA(at24_data_24c512, 524288 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA(at24_data_24c1024, 1048576 / 8, AT24_FLAG_ADDR16);
+AT24_CHIP_DATA_BS(at24_data_24c1025, 1048576 / 8, AT24_FLAG_ADDR16, 2);
+AT24_CHIP_DATA(at24_data_24c2048, 2097152 / 8, AT24_FLAG_ADDR16);
+/* identical to 24c08 ? */
+AT24_CHIP_DATA(at24_data_INT3499, 8192 / 8, 0);
+
+static const struct i2c_device_id at24_ids[] = {
+ { "24c00", (kernel_ulong_t)&at24_data_24c00 },
+ { "24c01", (kernel_ulong_t)&at24_data_24c01 },
+ { "24cs01", (kernel_ulong_t)&at24_data_24cs01 },
+ { "24c02", (kernel_ulong_t)&at24_data_24c02 },
+ { "24cs02", (kernel_ulong_t)&at24_data_24cs02 },
+ { "24mac402", (kernel_ulong_t)&at24_data_24mac402 },
+ { "24mac602", (kernel_ulong_t)&at24_data_24mac602 },
+ { "spd", (kernel_ulong_t)&at24_data_spd },
+ { "24c02-vaio", (kernel_ulong_t)&at24_data_24c02_vaio },
+ { "24c04", (kernel_ulong_t)&at24_data_24c04 },
+ { "24cs04", (kernel_ulong_t)&at24_data_24cs04 },
+ { "24c08", (kernel_ulong_t)&at24_data_24c08 },
+ { "24cs08", (kernel_ulong_t)&at24_data_24cs08 },
+ { "24c16", (kernel_ulong_t)&at24_data_24c16 },
+ { "24cs16", (kernel_ulong_t)&at24_data_24cs16 },
+ { "24c32", (kernel_ulong_t)&at24_data_24c32 },
+ { "24cs32", (kernel_ulong_t)&at24_data_24cs32 },
+ { "24c64", (kernel_ulong_t)&at24_data_24c64 },
+ { "24cs64", (kernel_ulong_t)&at24_data_24cs64 },
+ { "24c128", (kernel_ulong_t)&at24_data_24c128 },
+ { "24c256", (kernel_ulong_t)&at24_data_24c256 },
+ { "24c512", (kernel_ulong_t)&at24_data_24c512 },
+ { "24c1024", (kernel_ulong_t)&at24_data_24c1024 },
+ { "24c1025", (kernel_ulong_t)&at24_data_24c1025 },
+ { "24c2048", (kernel_ulong_t)&at24_data_24c2048 },
+ { "at24", 0 },
+ { /* END OF LIST */ }
+};
+MODULE_DEVICE_TABLE(i2c, at24_ids);
+
+static const struct of_device_id at24_of_match[] = {
+ { .compatible = "atmel,24c00", .data = &at24_data_24c00 },
+ { .compatible = "atmel,24c01", .data = &at24_data_24c01 },
+ { .compatible = "atmel,24cs01", .data = &at24_data_24cs01 },
+ { .compatible = "atmel,24c02", .data = &at24_data_24c02 },
+ { .compatible = "atmel,24cs02", .data = &at24_data_24cs02 },
+ { .compatible = "atmel,24mac402", .data = &at24_data_24mac402 },
+ { .compatible = "atmel,24mac602", .data = &at24_data_24mac602 },
+ { .compatible = "atmel,spd", .data = &at24_data_spd },
+ { .compatible = "atmel,24c04", .data = &at24_data_24c04 },
+ { .compatible = "atmel,24cs04", .data = &at24_data_24cs04 },
+ { .compatible = "atmel,24c08", .data = &at24_data_24c08 },
+ { .compatible = "atmel,24cs08", .data = &at24_data_24cs08 },
+ { .compatible = "atmel,24c16", .data = &at24_data_24c16 },
+ { .compatible = "atmel,24cs16", .data = &at24_data_24cs16 },
+ { .compatible = "atmel,24c32", .data = &at24_data_24c32 },
+ { .compatible = "atmel,24cs32", .data = &at24_data_24cs32 },
+ { .compatible = "atmel,24c64", .data = &at24_data_24c64 },
+ { .compatible = "atmel,24cs64", .data = &at24_data_24cs64 },
+ { .compatible = "atmel,24c128", .data = &at24_data_24c128 },
+ { .compatible = "atmel,24c256", .data = &at24_data_24c256 },
+ { .compatible = "atmel,24c512", .data = &at24_data_24c512 },
+ { .compatible = "atmel,24c1024", .data = &at24_data_24c1024 },
+ { .compatible = "atmel,24c1025", .data = &at24_data_24c1025 },
+ { .compatible = "atmel,24c2048", .data = &at24_data_24c2048 },
+ { /* END OF LIST */ },
+};
+MODULE_DEVICE_TABLE(of, at24_of_match);
+
+static const struct acpi_device_id __maybe_unused at24_acpi_ids[] = {
+ { "INT3499", (kernel_ulong_t)&at24_data_INT3499 },
+ { "TPF0001", (kernel_ulong_t)&at24_data_24c1024 },
+ { /* END OF LIST */ }
+};
+MODULE_DEVICE_TABLE(acpi, at24_acpi_ids);
+
+/*
+ * This routine supports chips which consume multiple I2C addresses. It
+ * computes the addressing information to be used for a given r/w request.
+ * Assumes that sanity checks for offset happened at sysfs-layer.
+ *
+ * Slave address and byte offset derive from the offset. Always
+ * set the byte address; on a multi-master board, another master
+ * may have changed the chip's "current" address pointer.
+ */
+static struct regmap *at24_translate_offset(struct at24_data *at24,
+ unsigned int *offset)
+{
+ unsigned int i;
+
+ if (at24->flags & AT24_FLAG_ADDR16) {
+ i = *offset >> 16;
+ *offset &= 0xffff;
+ } else {
+ i = *offset >> 8;
+ *offset &= 0xff;
+ }
+
+ return at24->client_regmaps[i];
+}
+
+static struct device *at24_base_client_dev(struct at24_data *at24)
+{
+ return regmap_get_device(at24->client_regmaps[0]);
+}
+
+static size_t at24_adjust_read_count(struct at24_data *at24,
+ unsigned int offset, size_t count)
+{
+ unsigned int bits;
+ size_t remainder;
+
+ /*
+ * In case of multi-address chips that don't rollover reads to
+ * the next slave address: truncate the count to the slave boundary,
+ * so that the read never straddles slaves.
+ */
+ if (at24->flags & AT24_FLAG_NO_RDROL) {
+ bits = (at24->flags & AT24_FLAG_ADDR16) ? 16 : 8;
+ remainder = BIT(bits) - offset;
+ if (count > remainder)
+ count = remainder;
+ }
+
+ if (count > at24_io_limit)
+ count = at24_io_limit;
+
+ return count;
+}
+
+static ssize_t at24_regmap_read(struct at24_data *at24, char *buf,
+ unsigned int offset, size_t count)
+{
+ unsigned long timeout, read_time;
+ struct regmap *regmap;
+ int ret;
+
+ regmap = at24_translate_offset(at24, &offset);
+ count = at24_adjust_read_count(at24, offset, count);
+
+ /* adjust offset for mac and serial read ops */
+ offset += at24->offset_adj;
+
+ timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
+ do {
+ /*
+ * The timestamp shall be taken before the actual operation
+ * to avoid a premature timeout in case of high CPU load.
+ */
+ read_time = jiffies;
+
+ ret = regmap_bulk_read(regmap, offset, buf, count);
+ dev_dbg(regmap_get_device(regmap), "read %zu@%d --> %d (%ld)\n",
+ count, offset, ret, jiffies);
+ if (!ret)
+ return count;
+
+ usleep_range(1000, 1500);
+ } while (time_before(read_time, timeout));
+
+ return -ETIMEDOUT;
+}
+
+/*
+ * Note that if the hardware write-protect pin is pulled high, the whole
+ * chip is normally write protected. But there are plenty of product
+ * variants here, including OTP fuses and partial chip protect.
+ *
+ * We only use page mode writes; the alternative is sloooow. These routines
+ * write at most one page.
+ */
+
+static size_t at24_adjust_write_count(struct at24_data *at24,
+ unsigned int offset, size_t count)
+{
+ unsigned int next_page;
+
+ /* write_max is at most a page */
+ if (count > at24->write_max)
+ count = at24->write_max;
+
+ /* Never roll over backwards, to the start of this page */
+ next_page = roundup(offset + 1, at24->page_size);
+ if (offset + count > next_page)
+ count = next_page - offset;
+
+ return count;
+}
+
+static ssize_t at24_regmap_write(struct at24_data *at24, const char *buf,
+ unsigned int offset, size_t count)
+{
+ unsigned long timeout, write_time;
+ struct regmap *regmap;
+ int ret;
+
+ regmap = at24_translate_offset(at24, &offset);
+ count = at24_adjust_write_count(at24, offset, count);
+ timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
+
+ do {
+ /*
+ * The timestamp shall be taken before the actual operation
+ * to avoid a premature timeout in case of high CPU load.
+ */
+ write_time = jiffies;
+
+ ret = regmap_bulk_write(regmap, offset, buf, count);
+ dev_dbg(regmap_get_device(regmap), "write %zu@%d --> %d (%ld)\n",
+ count, offset, ret, jiffies);
+ if (!ret)
+ return count;
+
+ usleep_range(1000, 1500);
+ } while (time_before(write_time, timeout));
+
+ return -ETIMEDOUT;
+}
+
+static int at24_read(void *priv, unsigned int off, void *val, size_t count)
+{
+ struct at24_data *at24;
+ struct device *dev;
+ char *buf = val;
+ int i, ret;
+
+ at24 = priv;
+ dev = at24_base_client_dev(at24);
+
+ if (unlikely(!count))
+ return count;
+
+ if (off + count > at24->byte_len)
+ return -EINVAL;
+
+ ret = pm_runtime_get_sync(dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(dev);
+ return ret;
+ }
+
+ /*
+ * Read data from chip, protecting against concurrent updates
+ * from this host, but not from other I2C masters.
+ */
+ mutex_lock(&at24->lock);
+
+ for (i = 0; count; i += ret, count -= ret) {
+ ret = at24_regmap_read(at24, buf + i, off + i, count);
+ if (ret < 0) {
+ mutex_unlock(&at24->lock);
+ pm_runtime_put(dev);
+ return ret;
+ }
+ }
+
+ mutex_unlock(&at24->lock);
+
+ pm_runtime_put(dev);
+
+ if (unlikely(at24->read_post))
+ at24->read_post(off, buf, i);
+
+ return 0;
+}
+
+static int at24_write(void *priv, unsigned int off, void *val, size_t count)
+{
+ struct at24_data *at24;
+ struct device *dev;
+ char *buf = val;
+ int ret;
+
+ at24 = priv;
+ dev = at24_base_client_dev(at24);
+
+ if (unlikely(!count))
+ return -EINVAL;
+
+ if (off + count > at24->byte_len)
+ return -EINVAL;
+
+ ret = pm_runtime_get_sync(dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(dev);
+ return ret;
+ }
+
+ /*
+ * Write data to chip, protecting against concurrent updates
+ * from this host, but not from other I2C masters.
+ */
+ mutex_lock(&at24->lock);
+
+ while (count) {
+ ret = at24_regmap_write(at24, buf, off, count);
+ if (ret < 0) {
+ mutex_unlock(&at24->lock);
+ pm_runtime_put(dev);
+ return ret;
+ }
+ buf += ret;
+ off += ret;
+ count -= ret;
+ }
+
+ mutex_unlock(&at24->lock);
+
+ pm_runtime_put(dev);
+
+ return 0;
+}
+
+static const struct at24_chip_data *at24_get_chip_data(struct device *dev)
+{
+ struct device_node *of_node = dev->of_node;
+ const struct at24_chip_data *cdata;
+ const struct i2c_device_id *id;
+
+ id = i2c_match_id(at24_ids, to_i2c_client(dev));
+
+ /*
+ * The I2C core allows OF nodes compatibles to match against the
+ * I2C device ID table as a fallback, so check not only if an OF
+ * node is present but also if it matches an OF device ID entry.
+ */
+ if (of_node && of_match_device(at24_of_match, dev))
+ cdata = of_device_get_match_data(dev);
+ else if (id)
+ cdata = (void *)id->driver_data;
+ else
+ cdata = acpi_device_get_match_data(dev);
+
+ if (!cdata)
+ return ERR_PTR(-ENODEV);
+
+ return cdata;
+}
+
+static int at24_make_dummy_client(struct at24_data *at24, unsigned int index,
+ struct i2c_client *base_client,
+ struct regmap_config *regmap_config)
+{
+ struct i2c_client *dummy_client;
+ struct regmap *regmap;
+
+ dummy_client = devm_i2c_new_dummy_device(&base_client->dev,
+ base_client->adapter,
+ base_client->addr +
+ (index << at24->bank_addr_shift));
+ if (IS_ERR(dummy_client))
+ return PTR_ERR(dummy_client);
+
+ regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ at24->client_regmaps[index] = regmap;
+
+ return 0;
+}
+
+static unsigned int at24_get_offset_adj(u8 flags, unsigned int byte_len)
+{
+ if (flags & AT24_FLAG_MAC) {
+ /* EUI-48 starts from 0x9a, EUI-64 from 0x98 */
+ return 0xa0 - byte_len;
+ } else if (flags & AT24_FLAG_SERIAL && flags & AT24_FLAG_ADDR16) {
+ /*
+ * For 16 bit address pointers, the word address must contain
+ * a '10' sequence in bits 11 and 10 regardless of the
+ * intended position of the address pointer.
+ */
+ return 0x0800;
+ } else if (flags & AT24_FLAG_SERIAL) {
+ /*
+ * Otherwise the word address must begin with a '10' sequence,
+ * regardless of the intended address.
+ */
+ return 0x0080;
+ } else {
+ return 0;
+ }
+}
+
+static int at24_probe(struct i2c_client *client)
+{
+ struct regmap_config regmap_config = { };
+ struct nvmem_config nvmem_config = { };
+ u32 byte_len, page_size, flags, addrw;
+ const struct at24_chip_data *cdata;
+ struct device *dev = &client->dev;
+ bool i2c_fn_i2c, i2c_fn_block;
+ unsigned int i, num_addresses;
+ struct at24_data *at24;
+ bool full_power;
+ struct regmap *regmap;
+ bool writable;
+ u8 test_byte;
+ int err;
+
+ i2c_fn_i2c = i2c_check_functionality(client->adapter, I2C_FUNC_I2C);
+ i2c_fn_block = i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_WRITE_I2C_BLOCK);
+
+ cdata = at24_get_chip_data(dev);
+ if (IS_ERR(cdata))
+ return PTR_ERR(cdata);
+
+ err = device_property_read_u32(dev, "pagesize", &page_size);
+ if (err)
+ /*
+ * This is slow, but we can't know all eeproms, so we better
+ * play safe. Specifying custom eeprom-types via device tree
+ * or properties is recommended anyhow.
+ */
+ page_size = 1;
+
+ flags = cdata->flags;
+ if (device_property_present(dev, "read-only"))
+ flags |= AT24_FLAG_READONLY;
+ if (device_property_present(dev, "no-read-rollover"))
+ flags |= AT24_FLAG_NO_RDROL;
+
+ err = device_property_read_u32(dev, "address-width", &addrw);
+ if (!err) {
+ switch (addrw) {
+ case 8:
+ if (flags & AT24_FLAG_ADDR16)
+ dev_warn(dev,
+ "Override address width to be 8, while default is 16\n");
+ flags &= ~AT24_FLAG_ADDR16;
+ break;
+ case 16:
+ flags |= AT24_FLAG_ADDR16;
+ break;
+ default:
+ dev_warn(dev, "Bad \"address-width\" property: %u\n",
+ addrw);
+ }
+ }
+
+ err = device_property_read_u32(dev, "size", &byte_len);
+ if (err)
+ byte_len = cdata->byte_len;
+
+ if (!i2c_fn_i2c && !i2c_fn_block)
+ page_size = 1;
+
+ if (!page_size) {
+ dev_err(dev, "page_size must not be 0!\n");
+ return -EINVAL;
+ }
+
+ if (!is_power_of_2(page_size))
+ dev_warn(dev, "page_size looks suspicious (no power of 2)!\n");
+
+ err = device_property_read_u32(dev, "num-addresses", &num_addresses);
+ if (err) {
+ if (flags & AT24_FLAG_TAKE8ADDR)
+ num_addresses = 8;
+ else
+ num_addresses = DIV_ROUND_UP(byte_len,
+ (flags & AT24_FLAG_ADDR16) ? 65536 : 256);
+ }
+
+ if ((flags & AT24_FLAG_SERIAL) && (flags & AT24_FLAG_MAC)) {
+ dev_err(dev,
+ "invalid device data - cannot have both AT24_FLAG_SERIAL & AT24_FLAG_MAC.");
+ return -EINVAL;
+ }
+
+ regmap_config.val_bits = 8;
+ regmap_config.reg_bits = (flags & AT24_FLAG_ADDR16) ? 16 : 8;
+ regmap_config.disable_locking = true;
+
+ regmap = devm_regmap_init_i2c(client, &regmap_config);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ at24 = devm_kzalloc(dev, struct_size(at24, client_regmaps, num_addresses),
+ GFP_KERNEL);
+ if (!at24)
+ return -ENOMEM;
+
+ mutex_init(&at24->lock);
+ at24->byte_len = byte_len;
+ at24->page_size = page_size;
+ at24->flags = flags;
+ at24->read_post = cdata->read_post;
+ at24->bank_addr_shift = cdata->bank_addr_shift;
+ at24->num_addresses = num_addresses;
+ at24->offset_adj = at24_get_offset_adj(flags, byte_len);
+ at24->client_regmaps[0] = regmap;
+
+ at24->vcc_reg = devm_regulator_get(dev, "vcc");
+ if (IS_ERR(at24->vcc_reg))
+ return PTR_ERR(at24->vcc_reg);
+
+ writable = !(flags & AT24_FLAG_READONLY);
+ if (writable) {
+ at24->write_max = min_t(unsigned int,
+ page_size, at24_io_limit);
+ if (!i2c_fn_i2c && at24->write_max > I2C_SMBUS_BLOCK_MAX)
+ at24->write_max = I2C_SMBUS_BLOCK_MAX;
+ }
+
+ /* use dummy devices for multiple-address chips */
+ for (i = 1; i < num_addresses; i++) {
+ err = at24_make_dummy_client(at24, i, client, &regmap_config);
+ if (err)
+ return err;
+ }
+
+ /*
+ * We initialize nvmem_config.id to NVMEM_DEVID_AUTO even if the
+ * label property is set as some platform can have multiple eeproms
+ * with same label and we can not register each of those with same
+ * label. Failing to register those eeproms trigger cascade failure
+ * on such platform.
+ */
+ nvmem_config.id = NVMEM_DEVID_AUTO;
+
+ if (device_property_present(dev, "label")) {
+ err = device_property_read_string(dev, "label",
+ &nvmem_config.name);
+ if (err)
+ return err;
+ } else {
+ nvmem_config.name = dev_name(dev);
+ }
+
+ nvmem_config.type = NVMEM_TYPE_EEPROM;
+ nvmem_config.dev = dev;
+ nvmem_config.read_only = !writable;
+ nvmem_config.root_only = !(flags & AT24_FLAG_IRUGO);
+ nvmem_config.owner = THIS_MODULE;
+ nvmem_config.compat = true;
+ nvmem_config.base_dev = dev;
+ nvmem_config.reg_read = at24_read;
+ nvmem_config.reg_write = at24_write;
+ nvmem_config.priv = at24;
+ nvmem_config.stride = 1;
+ nvmem_config.word_size = 1;
+ nvmem_config.size = byte_len;
+
+ i2c_set_clientdata(client, at24);
+
+ full_power = acpi_dev_state_d0(&client->dev);
+ if (full_power) {
+ err = regulator_enable(at24->vcc_reg);
+ if (err) {
+ dev_err(dev, "Failed to enable vcc regulator\n");
+ return err;
+ }
+
+ pm_runtime_set_active(dev);
+ }
+ pm_runtime_enable(dev);
+
+ at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
+ if (IS_ERR(at24->nvmem)) {
+ pm_runtime_disable(dev);
+ if (!pm_runtime_status_suspended(dev))
+ regulator_disable(at24->vcc_reg);
+ return PTR_ERR(at24->nvmem);
+ }
+
+ /*
+ * Perform a one-byte test read to verify that the chip is functional,
+ * unless powering on the device is to be avoided during probe (i.e.
+ * it's powered off right now).
+ */
+ if (full_power) {
+ err = at24_read(at24, 0, &test_byte, 1);
+ if (err) {
+ pm_runtime_disable(dev);
+ if (!pm_runtime_status_suspended(dev))
+ regulator_disable(at24->vcc_reg);
+ return -ENODEV;
+ }
+ }
+
+ pm_runtime_idle(dev);
+
+ if (writable)
+ dev_info(dev, "%u byte %s EEPROM, writable, %u bytes/write\n",
+ byte_len, client->name, at24->write_max);
+ else
+ dev_info(dev, "%u byte %s EEPROM, read-only\n",
+ byte_len, client->name);
+
+ return 0;
+}
+
+static void at24_remove(struct i2c_client *client)
+{
+ struct at24_data *at24 = i2c_get_clientdata(client);
+
+ pm_runtime_disable(&client->dev);
+ if (acpi_dev_state_d0(&client->dev)) {
+ if (!pm_runtime_status_suspended(&client->dev))
+ regulator_disable(at24->vcc_reg);
+ pm_runtime_set_suspended(&client->dev);
+ }
+}
+
+static int __maybe_unused at24_suspend(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct at24_data *at24 = i2c_get_clientdata(client);
+
+ return regulator_disable(at24->vcc_reg);
+}
+
+static int __maybe_unused at24_resume(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct at24_data *at24 = i2c_get_clientdata(client);
+
+ return regulator_enable(at24->vcc_reg);
+}
+
+static const struct dev_pm_ops at24_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+ pm_runtime_force_resume)
+ SET_RUNTIME_PM_OPS(at24_suspend, at24_resume, NULL)
+};
+
+static struct i2c_driver at24_driver = {
+ .driver = {
+ .name = "at24",
+ .pm = &at24_pm_ops,
+ .of_match_table = at24_of_match,
+ .acpi_match_table = ACPI_PTR(at24_acpi_ids),
+ },
+ .probe_new = at24_probe,
+ .remove = at24_remove,
+ .id_table = at24_ids,
+ .flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
+};
+
+static int __init at24_init(void)
+{
+ if (!at24_io_limit) {
+ pr_err("at24: at24_io_limit must not be 0!\n");
+ return -EINVAL;
+ }
+
+ at24_io_limit = rounddown_pow_of_two(at24_io_limit);
+ return i2c_add_driver(&at24_driver);
+}
+module_init(at24_init);
+
+static void __exit at24_exit(void)
+{
+ i2c_del_driver(&at24_driver);
+}
+module_exit(at24_exit);
+
+MODULE_DESCRIPTION("Driver for most I2C EEPROMs");
+MODULE_AUTHOR("David Brownell and Wolfram Sang");
+MODULE_LICENSE("GPL");
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
new file mode 100644
index 000000000..bdffc6543
--- /dev/null
+++ b/drivers/misc/eeprom/at25.c
@@ -0,0 +1,536 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for most of the SPI EEPROMs, such as Atmel AT25 models
+ * and Cypress FRAMs FM25 models.
+ *
+ * Copyright (C) 2006 David Brownell
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <linux/spi/eeprom.h>
+#include <linux/spi/spi.h>
+
+#include <linux/nvmem-provider.h>
+
+/*
+ * NOTE: this is an *EEPROM* driver. The vagaries of product naming
+ * mean that some AT25 products are EEPROMs, and others are FLASH.
+ * Handle FLASH chips with the drivers/mtd/devices/m25p80.c driver,
+ * not this one!
+ *
+ * EEPROMs that can be used with this driver include, for example:
+ * AT25M02, AT25128B
+ */
+
+#define FM25_SN_LEN 8 /* serial number length */
+#define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */
+
+struct at25_data {
+ struct spi_eeprom chip;
+ struct spi_device *spi;
+ struct mutex lock;
+ unsigned addrlen;
+ struct nvmem_config nvmem_config;
+ struct nvmem_device *nvmem;
+ u8 sernum[FM25_SN_LEN];
+ u8 command[EE_MAXADDRLEN + 1];
+};
+
+#define AT25_WREN 0x06 /* latch the write enable */
+#define AT25_WRDI 0x04 /* reset the write enable */
+#define AT25_RDSR 0x05 /* read status register */
+#define AT25_WRSR 0x01 /* write status register */
+#define AT25_READ 0x03 /* read byte(s) */
+#define AT25_WRITE 0x02 /* write byte(s)/sector */
+#define FM25_SLEEP 0xb9 /* enter sleep mode */
+#define FM25_RDID 0x9f /* read device ID */
+#define FM25_RDSN 0xc3 /* read S/N */
+
+#define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */
+#define AT25_SR_WEN 0x02 /* write enable (latched) */
+#define AT25_SR_BP0 0x04 /* BP for software writeprotect */
+#define AT25_SR_BP1 0x08
+#define AT25_SR_WPEN 0x80 /* writeprotect enable */
+
+#define AT25_INSTR_BIT3 0x08 /* additional address bit in instr */
+
+#define FM25_ID_LEN 9 /* ID length */
+
+/*
+ * Specs often allow 5ms for a page write, sometimes 20ms;
+ * it's important to recover from write timeouts.
+ */
+#define EE_TIMEOUT 25
+
+/*-------------------------------------------------------------------------*/
+
+#define io_limit PAGE_SIZE /* bytes */
+
+static int at25_ee_read(void *priv, unsigned int offset,
+ void *val, size_t count)
+{
+ struct at25_data *at25 = priv;
+ char *buf = val;
+ size_t max_chunk = spi_max_transfer_size(at25->spi);
+ unsigned int msg_offset = offset;
+ size_t bytes_left = count;
+ size_t segment;
+ u8 *cp;
+ ssize_t status;
+ struct spi_transfer t[2];
+ struct spi_message m;
+ u8 instr;
+
+ if (unlikely(offset >= at25->chip.byte_len))
+ return -EINVAL;
+ if ((offset + count) > at25->chip.byte_len)
+ count = at25->chip.byte_len - offset;
+ if (unlikely(!count))
+ return -EINVAL;
+
+ do {
+ segment = min(bytes_left, max_chunk);
+ cp = at25->command;
+
+ instr = AT25_READ;
+ if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR)
+ if (msg_offset >= BIT(at25->addrlen * 8))
+ instr |= AT25_INSTR_BIT3;
+
+ mutex_lock(&at25->lock);
+
+ *cp++ = instr;
+
+ /* 8/16/24-bit address is written MSB first */
+ switch (at25->addrlen) {
+ default: /* case 3 */
+ *cp++ = msg_offset >> 16;
+ fallthrough;
+ case 2:
+ *cp++ = msg_offset >> 8;
+ fallthrough;
+ case 1:
+ case 0: /* can't happen: for better code generation */
+ *cp++ = msg_offset >> 0;
+ }
+
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+
+ t[0].tx_buf = at25->command;
+ t[0].len = at25->addrlen + 1;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].rx_buf = buf;
+ t[1].len = segment;
+ spi_message_add_tail(&t[1], &m);
+
+ status = spi_sync(at25->spi, &m);
+
+ mutex_unlock(&at25->lock);
+
+ if (status)
+ return status;
+
+ msg_offset += segment;
+ buf += segment;
+ bytes_left -= segment;
+ } while (bytes_left > 0);
+
+ dev_dbg(&at25->spi->dev, "read %zu bytes at %d\n",
+ count, offset);
+ return 0;
+}
+
+/* Read extra registers as ID or serial number */
+static int fm25_aux_read(struct at25_data *at25, u8 *buf, uint8_t command,
+ int len)
+{
+ int status;
+ struct spi_transfer t[2];
+ struct spi_message m;
+
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+
+ t[0].tx_buf = at25->command;
+ t[0].len = 1;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].rx_buf = buf;
+ t[1].len = len;
+ spi_message_add_tail(&t[1], &m);
+
+ mutex_lock(&at25->lock);
+
+ at25->command[0] = command;
+
+ status = spi_sync(at25->spi, &m);
+ dev_dbg(&at25->spi->dev, "read %d aux bytes --> %d\n", len, status);
+
+ mutex_unlock(&at25->lock);
+ return status;
+}
+
+static ssize_t sernum_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct at25_data *at25;
+
+ at25 = dev_get_drvdata(dev);
+ return sysfs_emit(buf, "%*ph\n", (int)sizeof(at25->sernum), at25->sernum);
+}
+static DEVICE_ATTR_RO(sernum);
+
+static struct attribute *sernum_attrs[] = {
+ &dev_attr_sernum.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(sernum);
+
+static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
+{
+ struct at25_data *at25 = priv;
+ size_t maxsz = spi_max_transfer_size(at25->spi);
+ const char *buf = val;
+ int status = 0;
+ unsigned buf_size;
+ u8 *bounce;
+
+ if (unlikely(off >= at25->chip.byte_len))
+ return -EFBIG;
+ if ((off + count) > at25->chip.byte_len)
+ count = at25->chip.byte_len - off;
+ if (unlikely(!count))
+ return -EINVAL;
+
+ /* Temp buffer starts with command and address */
+ buf_size = at25->chip.page_size;
+ if (buf_size > io_limit)
+ buf_size = io_limit;
+ bounce = kmalloc(buf_size + at25->addrlen + 1, GFP_KERNEL);
+ if (!bounce)
+ return -ENOMEM;
+
+ /*
+ * For write, rollover is within the page ... so we write at
+ * most one page, then manually roll over to the next page.
+ */
+ mutex_lock(&at25->lock);
+ do {
+ unsigned long timeout, retries;
+ unsigned segment;
+ unsigned offset = off;
+ u8 *cp = bounce;
+ int sr;
+ u8 instr;
+
+ *cp = AT25_WREN;
+ status = spi_write(at25->spi, cp, 1);
+ if (status < 0) {
+ dev_dbg(&at25->spi->dev, "WREN --> %d\n", status);
+ break;
+ }
+
+ instr = AT25_WRITE;
+ if (at25->chip.flags & EE_INSTR_BIT3_IS_ADDR)
+ if (offset >= BIT(at25->addrlen * 8))
+ instr |= AT25_INSTR_BIT3;
+ *cp++ = instr;
+
+ /* 8/16/24-bit address is written MSB first */
+ switch (at25->addrlen) {
+ default: /* case 3 */
+ *cp++ = offset >> 16;
+ fallthrough;
+ case 2:
+ *cp++ = offset >> 8;
+ fallthrough;
+ case 1:
+ case 0: /* can't happen: for better code generation */
+ *cp++ = offset >> 0;
+ }
+
+ /* Write as much of a page as we can */
+ segment = buf_size - (offset % buf_size);
+ if (segment > count)
+ segment = count;
+ if (segment > maxsz)
+ segment = maxsz;
+ memcpy(cp, buf, segment);
+ status = spi_write(at25->spi, bounce,
+ segment + at25->addrlen + 1);
+ dev_dbg(&at25->spi->dev, "write %u bytes at %u --> %d\n",
+ segment, offset, status);
+ if (status < 0)
+ break;
+
+ /*
+ * REVISIT this should detect (or prevent) failed writes
+ * to read-only sections of the EEPROM...
+ */
+
+ /* Wait for non-busy status */
+ timeout = jiffies + msecs_to_jiffies(EE_TIMEOUT);
+ retries = 0;
+ do {
+
+ sr = spi_w8r8(at25->spi, AT25_RDSR);
+ if (sr < 0 || (sr & AT25_SR_nRDY)) {
+ dev_dbg(&at25->spi->dev,
+ "rdsr --> %d (%02x)\n", sr, sr);
+ /* at HZ=100, this is sloooow */
+ msleep(1);
+ continue;
+ }
+ if (!(sr & AT25_SR_nRDY))
+ break;
+ } while (retries++ < 3 || time_before_eq(jiffies, timeout));
+
+ if ((sr < 0) || (sr & AT25_SR_nRDY)) {
+ dev_err(&at25->spi->dev,
+ "write %u bytes offset %u, timeout after %u msecs\n",
+ segment, offset,
+ jiffies_to_msecs(jiffies -
+ (timeout - EE_TIMEOUT)));
+ status = -ETIMEDOUT;
+ break;
+ }
+
+ off += segment;
+ buf += segment;
+ count -= segment;
+
+ } while (count > 0);
+
+ mutex_unlock(&at25->lock);
+
+ kfree(bounce);
+ return status;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int at25_fw_to_chip(struct device *dev, struct spi_eeprom *chip)
+{
+ u32 val;
+ int err;
+
+ strscpy(chip->name, "at25", sizeof(chip->name));
+
+ err = device_property_read_u32(dev, "size", &val);
+ if (err)
+ err = device_property_read_u32(dev, "at25,byte-len", &val);
+ if (err) {
+ dev_err(dev, "Error: missing \"size\" property\n");
+ return err;
+ }
+ chip->byte_len = val;
+
+ err = device_property_read_u32(dev, "pagesize", &val);
+ if (err)
+ err = device_property_read_u32(dev, "at25,page-size", &val);
+ if (err) {
+ dev_err(dev, "Error: missing \"pagesize\" property\n");
+ return err;
+ }
+ chip->page_size = val;
+
+ err = device_property_read_u32(dev, "address-width", &val);
+ if (err) {
+ err = device_property_read_u32(dev, "at25,addr-mode", &val);
+ if (err) {
+ dev_err(dev, "Error: missing \"address-width\" property\n");
+ return err;
+ }
+ chip->flags = (u16)val;
+ } else {
+ switch (val) {
+ case 9:
+ chip->flags |= EE_INSTR_BIT3_IS_ADDR;
+ fallthrough;
+ case 8:
+ chip->flags |= EE_ADDR1;
+ break;
+ case 16:
+ chip->flags |= EE_ADDR2;
+ break;
+ case 24:
+ chip->flags |= EE_ADDR3;
+ break;
+ default:
+ dev_err(dev,
+ "Error: bad \"address-width\" property: %u\n",
+ val);
+ return -ENODEV;
+ }
+ if (device_property_present(dev, "read-only"))
+ chip->flags |= EE_READONLY;
+ }
+ return 0;
+}
+
+static int at25_fram_to_chip(struct device *dev, struct spi_eeprom *chip)
+{
+ struct at25_data *at25 = container_of(chip, struct at25_data, chip);
+ u8 sernum[FM25_SN_LEN];
+ u8 id[FM25_ID_LEN];
+ int i;
+
+ strscpy(chip->name, "fm25", sizeof(chip->name));
+
+ /* Get ID of chip */
+ fm25_aux_read(at25, id, FM25_RDID, FM25_ID_LEN);
+ if (id[6] != 0xc2) {
+ dev_err(dev, "Error: no Cypress FRAM (id %02x)\n", id[6]);
+ return -ENODEV;
+ }
+ /* Set size found in ID */
+ if (id[7] < 0x21 || id[7] > 0x26) {
+ dev_err(dev, "Error: unsupported size (id %02x)\n", id[7]);
+ return -ENODEV;
+ }
+
+ chip->byte_len = BIT(id[7] - 0x21 + 4) * 1024;
+ if (chip->byte_len > 64 * 1024)
+ chip->flags |= EE_ADDR3;
+ else
+ chip->flags |= EE_ADDR2;
+
+ if (id[8]) {
+ fm25_aux_read(at25, sernum, FM25_RDSN, FM25_SN_LEN);
+ /* Swap byte order */
+ for (i = 0; i < FM25_SN_LEN; i++)
+ at25->sernum[i] = sernum[FM25_SN_LEN - 1 - i];
+ }
+
+ chip->page_size = PAGE_SIZE;
+ return 0;
+}
+
+static const struct of_device_id at25_of_match[] = {
+ { .compatible = "atmel,at25" },
+ { .compatible = "cypress,fm25" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, at25_of_match);
+
+static const struct spi_device_id at25_spi_ids[] = {
+ { .name = "at25" },
+ { .name = "fm25" },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, at25_spi_ids);
+
+static int at25_probe(struct spi_device *spi)
+{
+ struct at25_data *at25 = NULL;
+ int err;
+ int sr;
+ struct spi_eeprom *pdata;
+ bool is_fram;
+
+ err = device_property_match_string(&spi->dev, "compatible", "cypress,fm25");
+ if (err >= 0)
+ is_fram = true;
+ else
+ is_fram = false;
+
+ /*
+ * Ping the chip ... the status register is pretty portable,
+ * unlike probing manufacturer IDs. We do expect that system
+ * firmware didn't write it in the past few milliseconds!
+ */
+ sr = spi_w8r8(spi, AT25_RDSR);
+ if (sr < 0 || sr & AT25_SR_nRDY) {
+ dev_dbg(&spi->dev, "rdsr --> %d (%02x)\n", sr, sr);
+ return -ENXIO;
+ }
+
+ at25 = devm_kzalloc(&spi->dev, sizeof(*at25), GFP_KERNEL);
+ if (!at25)
+ return -ENOMEM;
+
+ mutex_init(&at25->lock);
+ at25->spi = spi;
+ spi_set_drvdata(spi, at25);
+
+ /* Chip description */
+ pdata = dev_get_platdata(&spi->dev);
+ if (pdata) {
+ at25->chip = *pdata;
+ } else {
+ if (is_fram)
+ err = at25_fram_to_chip(&spi->dev, &at25->chip);
+ else
+ err = at25_fw_to_chip(&spi->dev, &at25->chip);
+ if (err)
+ return err;
+ }
+
+ /* For now we only support 8/16/24 bit addressing */
+ if (at25->chip.flags & EE_ADDR1)
+ at25->addrlen = 1;
+ else if (at25->chip.flags & EE_ADDR2)
+ at25->addrlen = 2;
+ else if (at25->chip.flags & EE_ADDR3)
+ at25->addrlen = 3;
+ else {
+ dev_dbg(&spi->dev, "unsupported address type\n");
+ return -EINVAL;
+ }
+
+ at25->nvmem_config.type = is_fram ? NVMEM_TYPE_FRAM : NVMEM_TYPE_EEPROM;
+ at25->nvmem_config.name = dev_name(&spi->dev);
+ at25->nvmem_config.dev = &spi->dev;
+ at25->nvmem_config.read_only = at25->chip.flags & EE_READONLY;
+ at25->nvmem_config.root_only = true;
+ at25->nvmem_config.owner = THIS_MODULE;
+ at25->nvmem_config.compat = true;
+ at25->nvmem_config.base_dev = &spi->dev;
+ at25->nvmem_config.reg_read = at25_ee_read;
+ at25->nvmem_config.reg_write = at25_ee_write;
+ at25->nvmem_config.priv = at25;
+ at25->nvmem_config.stride = 1;
+ at25->nvmem_config.word_size = 1;
+ at25->nvmem_config.size = at25->chip.byte_len;
+
+ at25->nvmem = devm_nvmem_register(&spi->dev, &at25->nvmem_config);
+ if (IS_ERR(at25->nvmem))
+ return PTR_ERR(at25->nvmem);
+
+ dev_info(&spi->dev, "%d %s %s %s%s, pagesize %u\n",
+ (at25->chip.byte_len < 1024) ?
+ at25->chip.byte_len : (at25->chip.byte_len / 1024),
+ (at25->chip.byte_len < 1024) ? "Byte" : "KByte",
+ at25->chip.name, is_fram ? "fram" : "eeprom",
+ (at25->chip.flags & EE_READONLY) ? " (readonly)" : "",
+ at25->chip.page_size);
+ return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct spi_driver at25_driver = {
+ .driver = {
+ .name = "at25",
+ .of_match_table = at25_of_match,
+ .dev_groups = sernum_groups,
+ },
+ .probe = at25_probe,
+ .id_table = at25_spi_ids,
+};
+
+module_spi_driver(at25_driver);
+
+MODULE_DESCRIPTION("Driver for most SPI EEPROMs");
+MODULE_AUTHOR("David Brownell");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:at25");
diff --git a/drivers/misc/eeprom/digsy_mtc_eeprom.c b/drivers/misc/eeprom/digsy_mtc_eeprom.c
new file mode 100644
index 000000000..f1f766b70
--- /dev/null
+++ b/drivers/misc/eeprom/digsy_mtc_eeprom.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * EEPROMs access control driver for display configuration EEPROMs
+ * on DigsyMTC board.
+ *
+ * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
+ *
+ * FIXME: this driver is used on a device-tree probed platform: it
+ * should be defined as a bit-banged SPI device and probed from the device
+ * tree and not like this with static grabbing of a few numbered GPIO
+ * lines at random.
+ *
+ * Add proper SPI and EEPROM in arch/powerpc/boot/dts/digsy_mtc.dts
+ * and delete this driver.
+ */
+
+#include <linux/gpio.h>
+#include <linux/gpio/machine.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_gpio.h>
+#include <linux/eeprom_93xx46.h>
+
+#define GPIO_EEPROM_CLK 216
+#define GPIO_EEPROM_CS 210
+#define GPIO_EEPROM_DI 217
+#define GPIO_EEPROM_DO 249
+#define GPIO_EEPROM_OE 255
+#define EE_SPI_BUS_NUM 1
+
+static void digsy_mtc_op_prepare(void *p)
+{
+ /* enable */
+ gpio_set_value(GPIO_EEPROM_OE, 0);
+}
+
+static void digsy_mtc_op_finish(void *p)
+{
+ /* disable */
+ gpio_set_value(GPIO_EEPROM_OE, 1);
+}
+
+struct eeprom_93xx46_platform_data digsy_mtc_eeprom_data = {
+ .flags = EE_ADDR8,
+ .prepare = digsy_mtc_op_prepare,
+ .finish = digsy_mtc_op_finish,
+};
+
+static struct spi_gpio_platform_data eeprom_spi_gpio_data = {
+ .num_chipselect = 1,
+};
+
+static struct platform_device digsy_mtc_eeprom = {
+ .name = "spi_gpio",
+ .id = EE_SPI_BUS_NUM,
+ .dev = {
+ .platform_data = &eeprom_spi_gpio_data,
+ },
+};
+
+static struct gpiod_lookup_table eeprom_spi_gpiod_table = {
+ .dev_id = "spi_gpio",
+ .table = {
+ GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CLK,
+ "sck", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DI,
+ "mosi", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_DO,
+ "miso", GPIO_ACTIVE_HIGH),
+ GPIO_LOOKUP("gpio@b00", GPIO_EEPROM_CS,
+ "cs", GPIO_ACTIVE_HIGH),
+ { },
+ },
+};
+
+static struct spi_board_info digsy_mtc_eeprom_info[] __initdata = {
+ {
+ .modalias = "93xx46",
+ .max_speed_hz = 1000000,
+ .bus_num = EE_SPI_BUS_NUM,
+ .chip_select = 0,
+ .mode = SPI_MODE_0,
+ .platform_data = &digsy_mtc_eeprom_data,
+ },
+};
+
+static int __init digsy_mtc_eeprom_devices_init(void)
+{
+ int ret;
+
+ ret = gpio_request_one(GPIO_EEPROM_OE, GPIOF_OUT_INIT_HIGH,
+ "93xx46 EEPROMs OE");
+ if (ret) {
+ pr_err("can't request gpio %d\n", GPIO_EEPROM_OE);
+ return ret;
+ }
+ gpiod_add_lookup_table(&eeprom_spi_gpiod_table);
+ spi_register_board_info(digsy_mtc_eeprom_info,
+ ARRAY_SIZE(digsy_mtc_eeprom_info));
+ return platform_device_register(&digsy_mtc_eeprom);
+}
+device_initcall(digsy_mtc_eeprom_devices_init);
diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
new file mode 100644
index 000000000..c8c6deb7e
--- /dev/null
+++ b/drivers/misc/eeprom/ee1004.c
@@ -0,0 +1,245 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ee1004 - driver for DDR4 SPD EEPROMs
+ *
+ * Copyright (C) 2017-2019 Jean Delvare
+ *
+ * Based on the at24 driver:
+ * Copyright (C) 2005-2007 David Brownell
+ * Copyright (C) 2008 Wolfram Sang, Pengutronix
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+/*
+ * DDR4 memory modules use special EEPROMs following the Jedec EE1004
+ * specification. These are 512-byte EEPROMs using a single I2C address
+ * in the 0x50-0x57 range for data. One of two 256-byte page is selected
+ * by writing a command to I2C address 0x36 or 0x37 on the same I2C bus.
+ *
+ * Therefore we need to request these 2 additional addresses, and serialize
+ * access to all such EEPROMs with a single mutex.
+ *
+ * We assume it is safe to read up to 32 bytes at once from these EEPROMs.
+ * We use SMBus access even if I2C is available, these EEPROMs are small
+ * enough, and reading from them infrequent enough, that we favor simplicity
+ * over performance.
+ */
+
+#define EE1004_ADDR_SET_PAGE 0x36
+#define EE1004_NUM_PAGES 2
+#define EE1004_PAGE_SIZE 256
+#define EE1004_PAGE_SHIFT 8
+#define EE1004_EEPROM_SIZE (EE1004_PAGE_SIZE * EE1004_NUM_PAGES)
+
+/*
+ * Mutex protects ee1004_set_page and ee1004_dev_count, and must be held
+ * from page selection to end of read.
+ */
+static DEFINE_MUTEX(ee1004_bus_lock);
+static struct i2c_client *ee1004_set_page[EE1004_NUM_PAGES];
+static unsigned int ee1004_dev_count;
+static int ee1004_current_page;
+
+static const struct i2c_device_id ee1004_ids[] = {
+ { "ee1004", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ee1004_ids);
+
+/*-------------------------------------------------------------------------*/
+
+static int ee1004_get_current_page(void)
+{
+ int err;
+
+ err = i2c_smbus_read_byte(ee1004_set_page[0]);
+ if (err == -ENXIO) {
+ /* Nack means page 1 is selected */
+ return 1;
+ }
+ if (err < 0) {
+ /* Anything else is a real error, bail out */
+ return err;
+ }
+
+ /* Ack means page 0 is selected, returned value meaningless */
+ return 0;
+}
+
+static int ee1004_set_current_page(struct device *dev, int page)
+{
+ int ret;
+
+ if (page == ee1004_current_page)
+ return 0;
+
+ /* Data is ignored */
+ ret = i2c_smbus_write_byte(ee1004_set_page[page], 0x00);
+ /*
+ * Don't give up just yet. Some memory modules will select the page
+ * but not ack the command. Check which page is selected now.
+ */
+ if (ret == -ENXIO && ee1004_get_current_page() == page)
+ ret = 0;
+ if (ret < 0) {
+ dev_err(dev, "Failed to select page %d (%d)\n", page, ret);
+ return ret;
+ }
+
+ dev_dbg(dev, "Selected page %d\n", page);
+ ee1004_current_page = page;
+
+ return 0;
+}
+
+static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf,
+ unsigned int offset, size_t count)
+{
+ int status, page;
+
+ page = offset >> EE1004_PAGE_SHIFT;
+ offset &= (1 << EE1004_PAGE_SHIFT) - 1;
+
+ status = ee1004_set_current_page(&client->dev, page);
+ if (status)
+ return status;
+
+ /* Can't cross page boundaries */
+ if (offset + count > EE1004_PAGE_SIZE)
+ count = EE1004_PAGE_SIZE - offset;
+
+ if (count > I2C_SMBUS_BLOCK_MAX)
+ count = I2C_SMBUS_BLOCK_MAX;
+
+ return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf);
+}
+
+static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct i2c_client *client = kobj_to_i2c_client(kobj);
+ size_t requested = count;
+ int ret = 0;
+
+ /*
+ * Read data from chip, protecting against concurrent access to
+ * other EE1004 SPD EEPROMs on the same adapter.
+ */
+ mutex_lock(&ee1004_bus_lock);
+
+ while (count) {
+ ret = ee1004_eeprom_read(client, buf, off, count);
+ if (ret < 0)
+ goto out;
+
+ buf += ret;
+ off += ret;
+ count -= ret;
+ }
+out:
+ mutex_unlock(&ee1004_bus_lock);
+
+ return ret < 0 ? ret : requested;
+}
+
+static BIN_ATTR_RO(eeprom, EE1004_EEPROM_SIZE);
+
+static struct bin_attribute *ee1004_attrs[] = {
+ &bin_attr_eeprom,
+ NULL
+};
+
+BIN_ATTRIBUTE_GROUPS(ee1004);
+
+static void ee1004_cleanup(int idx)
+{
+ if (--ee1004_dev_count == 0)
+ while (--idx >= 0) {
+ i2c_unregister_device(ee1004_set_page[idx]);
+ ee1004_set_page[idx] = NULL;
+ }
+}
+
+static int ee1004_probe(struct i2c_client *client)
+{
+ int err, cnr = 0;
+
+ /* Make sure we can operate on this adapter */
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_I2C_BLOCK) &&
+ !i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_BYTE_DATA))
+ return -EPFNOSUPPORT;
+
+ /* Use 2 dummy devices for page select command */
+ mutex_lock(&ee1004_bus_lock);
+ if (++ee1004_dev_count == 1) {
+ for (cnr = 0; cnr < EE1004_NUM_PAGES; cnr++) {
+ struct i2c_client *cl;
+
+ cl = i2c_new_dummy_device(client->adapter, EE1004_ADDR_SET_PAGE + cnr);
+ if (IS_ERR(cl)) {
+ err = PTR_ERR(cl);
+ goto err_clients;
+ }
+ ee1004_set_page[cnr] = cl;
+ }
+
+ /* Remember current page to avoid unneeded page select */
+ err = ee1004_get_current_page();
+ if (err < 0)
+ goto err_clients;
+ dev_dbg(&client->dev, "Currently selected page: %d\n", err);
+ ee1004_current_page = err;
+ } else if (client->adapter != ee1004_set_page[0]->adapter) {
+ dev_err(&client->dev,
+ "Driver only supports devices on a single I2C bus\n");
+ err = -EOPNOTSUPP;
+ goto err_clients;
+ }
+ mutex_unlock(&ee1004_bus_lock);
+
+ dev_info(&client->dev,
+ "%u byte EE1004-compliant SPD EEPROM, read-only\n",
+ EE1004_EEPROM_SIZE);
+
+ return 0;
+
+ err_clients:
+ ee1004_cleanup(cnr);
+ mutex_unlock(&ee1004_bus_lock);
+
+ return err;
+}
+
+static void ee1004_remove(struct i2c_client *client)
+{
+ /* Remove page select clients if this is the last device */
+ mutex_lock(&ee1004_bus_lock);
+ ee1004_cleanup(EE1004_NUM_PAGES);
+ mutex_unlock(&ee1004_bus_lock);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static struct i2c_driver ee1004_driver = {
+ .driver = {
+ .name = "ee1004",
+ .dev_groups = ee1004_groups,
+ },
+ .probe_new = ee1004_probe,
+ .remove = ee1004_remove,
+ .id_table = ee1004_ids,
+};
+module_i2c_driver(ee1004_driver);
+
+MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs");
+MODULE_AUTHOR("Jean Delvare");
+MODULE_LICENSE("GPL");
diff --git a/drivers/misc/eeprom/eeprom.c b/drivers/misc/eeprom/eeprom.c
new file mode 100644
index 000000000..8a841a75d
--- /dev/null
+++ b/drivers/misc/eeprom/eeprom.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl> and
+ * Philip Edelbrock <phil@netroedge.com>
+ * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (C) 2003 IBM Corp.
+ * Copyright (C) 2004 Jean Delvare <jdelvare@suse.de>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/capability.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = { 0x50, 0x51, 0x52, 0x53, 0x54,
+ 0x55, 0x56, 0x57, I2C_CLIENT_END };
+
+
+/* Size of EEPROM in bytes */
+#define EEPROM_SIZE 256
+
+/* possible types of eeprom devices */
+enum eeprom_nature {
+ UNKNOWN,
+ VAIO,
+};
+
+/* Each client has this additional data */
+struct eeprom_data {
+ struct mutex update_lock;
+ u8 valid; /* bitfield, bit!=0 if slice is valid */
+ unsigned long last_updated[8]; /* In jiffies, 8 slices */
+ u8 data[EEPROM_SIZE]; /* Register values */
+ enum eeprom_nature nature;
+};
+
+
+static void eeprom_update_client(struct i2c_client *client, u8 slice)
+{
+ struct eeprom_data *data = i2c_get_clientdata(client);
+ int i;
+
+ mutex_lock(&data->update_lock);
+
+ if (!(data->valid & (1 << slice)) ||
+ time_after(jiffies, data->last_updated[slice] + 300 * HZ)) {
+ dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
+
+ if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ for (i = slice << 5; i < (slice + 1) << 5; i += 32)
+ if (i2c_smbus_read_i2c_block_data(client, i,
+ 32, data->data + i)
+ != 32)
+ goto exit;
+ } else {
+ for (i = slice << 5; i < (slice + 1) << 5; i += 2) {
+ int word = i2c_smbus_read_word_data(client, i);
+ if (word < 0)
+ goto exit;
+ data->data[i] = word & 0xff;
+ data->data[i + 1] = word >> 8;
+ }
+ }
+ data->last_updated[slice] = jiffies;
+ data->valid |= (1 << slice);
+ }
+exit:
+ mutex_unlock(&data->update_lock);
+}
+
+static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct i2c_client *client = kobj_to_i2c_client(kobj);
+ struct eeprom_data *data = i2c_get_clientdata(client);
+ u8 slice;
+
+ /* Only refresh slices which contain requested bytes */
+ for (slice = off >> 5; slice <= (off + count - 1) >> 5; slice++)
+ eeprom_update_client(client, slice);
+
+ /* Hide Vaio private settings to regular users:
+ - BIOS passwords: bytes 0x00 to 0x0f
+ - UUID: bytes 0x10 to 0x1f
+ - Serial number: 0xc0 to 0xdf */
+ if (data->nature == VAIO && !capable(CAP_SYS_ADMIN)) {
+ int i;
+
+ for (i = 0; i < count; i++) {
+ if ((off + i <= 0x1f) ||
+ (off + i >= 0xc0 && off + i <= 0xdf))
+ buf[i] = 0;
+ else
+ buf[i] = data->data[off + i];
+ }
+ } else {
+ memcpy(buf, &data->data[off], count);
+ }
+
+ return count;
+}
+
+static const struct bin_attribute eeprom_attr = {
+ .attr = {
+ .name = "eeprom",
+ .mode = S_IRUGO,
+ },
+ .size = EEPROM_SIZE,
+ .read = eeprom_read,
+};
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int eeprom_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter = client->adapter;
+
+ /* EDID EEPROMs are often 24C00 EEPROMs, which answer to all
+ addresses 0x50-0x57, but we only care about 0x50. So decline
+ attaching to addresses >= 0x51 on DDC buses */
+ if (!(adapter->class & I2C_CLASS_SPD) && client->addr >= 0x51)
+ return -ENODEV;
+
+ /* There are four ways we can read the EEPROM data:
+ (1) I2C block reads (faster, but unsupported by most adapters)
+ (2) Word reads (128% overhead)
+ (3) Consecutive byte reads (88% overhead, unsafe)
+ (4) Regular byte data reads (265% overhead)
+ The third and fourth methods are not implemented by this driver
+ because all known adapters support one of the first two. */
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)
+ && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
+ return -ENODEV;
+
+ strscpy(info->type, "eeprom", I2C_NAME_SIZE);
+
+ return 0;
+}
+
+static int eeprom_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ struct eeprom_data *data;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct eeprom_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ memset(data->data, 0xff, EEPROM_SIZE);
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->update_lock);
+ data->nature = UNKNOWN;
+
+ /* Detect the Vaio nature of EEPROMs.
+ We use the "PCG-" or "VGN-" prefix as the signature. */
+ if (client->addr == 0x57
+ && i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+ char name[4];
+
+ name[0] = i2c_smbus_read_byte_data(client, 0x80);
+ name[1] = i2c_smbus_read_byte_data(client, 0x81);
+ name[2] = i2c_smbus_read_byte_data(client, 0x82);
+ name[3] = i2c_smbus_read_byte_data(client, 0x83);
+
+ if (!memcmp(name, "PCG-", 4) || !memcmp(name, "VGN-", 4)) {
+ dev_info(&client->dev, "Vaio EEPROM detected, "
+ "enabling privacy protection\n");
+ data->nature = VAIO;
+ }
+ }
+
+ /* Let the users know they are using deprecated driver */
+ dev_notice(&client->dev,
+ "eeprom driver is deprecated, please use at24 instead\n");
+
+ /* create the sysfs eeprom file */
+ return sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
+}
+
+static void eeprom_remove(struct i2c_client *client)
+{
+ sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
+}
+
+static const struct i2c_device_id eeprom_id[] = {
+ { "eeprom", 0 },
+ { }
+};
+
+static struct i2c_driver eeprom_driver = {
+ .driver = {
+ .name = "eeprom",
+ },
+ .probe = eeprom_probe,
+ .remove = eeprom_remove,
+ .id_table = eeprom_id,
+
+ .class = I2C_CLASS_DDC | I2C_CLASS_SPD,
+ .detect = eeprom_detect,
+ .address_list = normal_i2c,
+};
+
+module_i2c_driver(eeprom_driver);
+
+MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
+ "Philip Edelbrock <phil@netroedge.com> and "
+ "Greg Kroah-Hartman <greg@kroah.com>");
+MODULE_DESCRIPTION("I2C EEPROM driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c
new file mode 100644
index 000000000..9627294fe
--- /dev/null
+++ b/drivers/misc/eeprom/eeprom_93cx6.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2004 - 2006 rt2x00 SourceForge Project
+ * <http://rt2x00.serialmonkey.com>
+ *
+ * Module: eeprom_93cx6
+ * Abstract: EEPROM reader routines for 93cx6 chipsets.
+ * Supported chipsets: 93c46 & 93c66.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/eeprom_93cx6.h>
+
+MODULE_AUTHOR("http://rt2x00.serialmonkey.com");
+MODULE_VERSION("1.0");
+MODULE_DESCRIPTION("EEPROM 93cx6 chip driver");
+MODULE_LICENSE("GPL");
+
+static inline void eeprom_93cx6_pulse_high(struct eeprom_93cx6 *eeprom)
+{
+ eeprom->reg_data_clock = 1;
+ eeprom->register_write(eeprom);
+
+ /*
+ * Add a short delay for the pulse to work.
+ * According to the specifications the "maximum minimum"
+ * time should be 450ns.
+ */
+ ndelay(450);
+}
+
+static inline void eeprom_93cx6_pulse_low(struct eeprom_93cx6 *eeprom)
+{
+ eeprom->reg_data_clock = 0;
+ eeprom->register_write(eeprom);
+
+ /*
+ * Add a short delay for the pulse to work.
+ * According to the specifications the "maximum minimum"
+ * time should be 450ns.
+ */
+ ndelay(450);
+}
+
+static void eeprom_93cx6_startup(struct eeprom_93cx6 *eeprom)
+{
+ /*
+ * Clear all flags, and enable chip select.
+ */
+ eeprom->register_read(eeprom);
+ eeprom->reg_data_in = 0;
+ eeprom->reg_data_out = 0;
+ eeprom->reg_data_clock = 0;
+ eeprom->reg_chip_select = 1;
+ eeprom->drive_data = 1;
+ eeprom->register_write(eeprom);
+
+ /*
+ * kick a pulse.
+ */
+ eeprom_93cx6_pulse_high(eeprom);
+ eeprom_93cx6_pulse_low(eeprom);
+}
+
+static void eeprom_93cx6_cleanup(struct eeprom_93cx6 *eeprom)
+{
+ /*
+ * Clear chip_select and data_in flags.
+ */
+ eeprom->register_read(eeprom);
+ eeprom->reg_data_in = 0;
+ eeprom->reg_chip_select = 0;
+ eeprom->register_write(eeprom);
+
+ /*
+ * kick a pulse.
+ */
+ eeprom_93cx6_pulse_high(eeprom);
+ eeprom_93cx6_pulse_low(eeprom);
+}
+
+static void eeprom_93cx6_write_bits(struct eeprom_93cx6 *eeprom,
+ const u16 data, const u16 count)
+{
+ unsigned int i;
+
+ eeprom->register_read(eeprom);
+
+ /*
+ * Clear data flags.
+ */
+ eeprom->reg_data_in = 0;
+ eeprom->reg_data_out = 0;
+ eeprom->drive_data = 1;
+
+ /*
+ * Start writing all bits.
+ */
+ for (i = count; i > 0; i--) {
+ /*
+ * Check if this bit needs to be set.
+ */
+ eeprom->reg_data_in = !!(data & (1 << (i - 1)));
+
+ /*
+ * Write the bit to the eeprom register.
+ */
+ eeprom->register_write(eeprom);
+
+ /*
+ * Kick a pulse.
+ */
+ eeprom_93cx6_pulse_high(eeprom);
+ eeprom_93cx6_pulse_low(eeprom);
+ }
+
+ eeprom->reg_data_in = 0;
+ eeprom->register_write(eeprom);
+}
+
+static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
+ u16 *data, const u16 count)
+{
+ unsigned int i;
+ u16 buf = 0;
+
+ eeprom->register_read(eeprom);
+
+ /*
+ * Clear data flags.
+ */
+ eeprom->reg_data_in = 0;
+ eeprom->reg_data_out = 0;
+ eeprom->drive_data = 0;
+
+ /*
+ * Start reading all bits.
+ */
+ for (i = count; i > 0; i--) {
+ eeprom_93cx6_pulse_high(eeprom);
+
+ eeprom->register_read(eeprom);
+
+ /*
+ * Clear data_in flag.
+ */
+ eeprom->reg_data_in = 0;
+
+ /*
+ * Read if the bit has been set.
+ */
+ if (eeprom->reg_data_out)
+ buf |= (1 << (i - 1));
+
+ eeprom_93cx6_pulse_low(eeprom);
+ }
+
+ *data = buf;
+}
+
+/**
+ * eeprom_93cx6_read - Read a word from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @word: Word index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ *
+ * This function will read the eeprom data as host-endian word
+ * into the given data pointer.
+ */
+void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word,
+ u16 *data)
+{
+ u16 command;
+
+ /*
+ * Initialize the eeprom register
+ */
+ eeprom_93cx6_startup(eeprom);
+
+ /*
+ * Select the read opcode and the word to be read.
+ */
+ command = (PCI_EEPROM_READ_OPCODE << eeprom->width) | word;
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+ /*
+ * Read the requested 16 bits.
+ */
+ eeprom_93cx6_read_bits(eeprom, data, 16);
+
+ /*
+ * Cleanup eeprom register.
+ */
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_read);
+
+/**
+ * eeprom_93cx6_multiread - Read multiple words from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @word: Word index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ * @words: Number of words that should be read.
+ *
+ * This function will read all requested words from the eeprom,
+ * this is done by calling eeprom_93cx6_read() multiple times.
+ * But with the additional change that while the eeprom_93cx6_read
+ * will return host ordered bytes, this method will return little
+ * endian words.
+ */
+void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
+ __le16 *data, const u16 words)
+{
+ unsigned int i;
+ u16 tmp;
+
+ for (i = 0; i < words; i++) {
+ tmp = 0;
+ eeprom_93cx6_read(eeprom, word + i, &tmp);
+ data[i] = cpu_to_le16(tmp);
+ }
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);
+
+/**
+ * eeprom_93cx6_readb - Read a byte from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @byte: Byte index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ *
+ * This function will read a byte of the eeprom data
+ * into the given data pointer.
+ */
+void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte,
+ u8 *data)
+{
+ u16 command;
+ u16 tmp;
+
+ /*
+ * Initialize the eeprom register
+ */
+ eeprom_93cx6_startup(eeprom);
+
+ /*
+ * Select the read opcode and the byte to be read.
+ */
+ command = (PCI_EEPROM_READ_OPCODE << (eeprom->width + 1)) | byte;
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1);
+
+ /*
+ * Read the requested 8 bits.
+ */
+ eeprom_93cx6_read_bits(eeprom, &tmp, 8);
+ *data = tmp & 0xff;
+
+ /*
+ * Cleanup eeprom register.
+ */
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_readb);
+
+/**
+ * eeprom_93cx6_multireadb - Read multiple bytes from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @byte: Index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ * @bytes: Number of bytes that should be read.
+ *
+ * This function will read all requested bytes from the eeprom,
+ * this is done by calling eeprom_93cx6_readb() multiple times.
+ */
+void eeprom_93cx6_multireadb(struct eeprom_93cx6 *eeprom, const u8 byte,
+ u8 *data, const u16 bytes)
+{
+ unsigned int i;
+
+ for (i = 0; i < bytes; i++)
+ eeprom_93cx6_readb(eeprom, byte + i, &data[i]);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_multireadb);
+
+/**
+ * eeprom_93cx6_wren - set the write enable state
+ * @eeprom: Pointer to eeprom structure
+ * @enable: true to enable writes, otherwise disable writes
+ *
+ * Set the EEPROM write enable state to either allow or deny
+ * writes depending on the @enable value.
+ */
+void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable)
+{
+ u16 command;
+
+ /* start the command */
+ eeprom_93cx6_startup(eeprom);
+
+ /* create command to enable/disable */
+
+ command = enable ? PCI_EEPROM_EWEN_OPCODE : PCI_EEPROM_EWDS_OPCODE;
+ command <<= (eeprom->width - 2);
+
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_wren);
+
+/**
+ * eeprom_93cx6_write - write data to the EEPROM
+ * @eeprom: Pointer to eeprom structure
+ * @addr: Address to write data to.
+ * @data: The data to write to address @addr.
+ *
+ * Write the @data to the specified @addr in the EEPROM and
+ * waiting for the device to finish writing.
+ *
+ * Note, since we do not expect large number of write operations
+ * we delay in between parts of the operation to avoid using excessive
+ * amounts of CPU time busy waiting.
+ */
+void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data)
+{
+ int timeout = 100;
+ u16 command;
+
+ /* start the command */
+ eeprom_93cx6_startup(eeprom);
+
+ command = PCI_EEPROM_WRITE_OPCODE << eeprom->width;
+ command |= addr;
+
+ /* send write command */
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width);
+
+ /* send data */
+ eeprom_93cx6_write_bits(eeprom, data, 16);
+
+ /* get ready to check for busy */
+ eeprom->drive_data = 0;
+ eeprom->reg_chip_select = 1;
+ eeprom->register_write(eeprom);
+
+ /* wait at-least 250ns to get DO to be the busy signal */
+ usleep_range(1000, 2000);
+
+ /* wait for DO to go high to signify finish */
+
+ while (true) {
+ eeprom->register_read(eeprom);
+
+ if (eeprom->reg_data_out)
+ break;
+
+ usleep_range(1000, 2000);
+
+ if (--timeout <= 0) {
+ printk(KERN_ERR "%s: timeout\n", __func__);
+ break;
+ }
+ }
+
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_write);
diff --git a/drivers/misc/eeprom/eeprom_93xx46.c b/drivers/misc/eeprom/eeprom_93xx46.c
new file mode 100644
index 000000000..b630625b3
--- /dev/null
+++ b/drivers/misc/eeprom/eeprom_93xx46.c
@@ -0,0 +1,583 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for 93xx46 EEPROMs
+ *
+ * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/nvmem-provider.h>
+#include <linux/eeprom_93xx46.h>
+
+#define OP_START 0x4
+#define OP_WRITE (OP_START | 0x1)
+#define OP_READ (OP_START | 0x2)
+#define ADDR_EWDS 0x00
+#define ADDR_ERAL 0x20
+#define ADDR_EWEN 0x30
+
+struct eeprom_93xx46_devtype_data {
+ unsigned int quirks;
+ unsigned char flags;
+};
+
+static const struct eeprom_93xx46_devtype_data at93c46_data = {
+ .flags = EE_SIZE1K,
+};
+
+static const struct eeprom_93xx46_devtype_data at93c56_data = {
+ .flags = EE_SIZE2K,
+};
+
+static const struct eeprom_93xx46_devtype_data at93c66_data = {
+ .flags = EE_SIZE4K,
+};
+
+static const struct eeprom_93xx46_devtype_data atmel_at93c46d_data = {
+ .flags = EE_SIZE1K,
+ .quirks = EEPROM_93XX46_QUIRK_SINGLE_WORD_READ |
+ EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH,
+};
+
+static const struct eeprom_93xx46_devtype_data microchip_93lc46b_data = {
+ .flags = EE_SIZE1K,
+ .quirks = EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE,
+};
+
+struct eeprom_93xx46_dev {
+ struct spi_device *spi;
+ struct eeprom_93xx46_platform_data *pdata;
+ struct mutex lock;
+ struct nvmem_config nvmem_config;
+ struct nvmem_device *nvmem;
+ int addrlen;
+ int size;
+};
+
+static inline bool has_quirk_single_word_read(struct eeprom_93xx46_dev *edev)
+{
+ return edev->pdata->quirks & EEPROM_93XX46_QUIRK_SINGLE_WORD_READ;
+}
+
+static inline bool has_quirk_instruction_length(struct eeprom_93xx46_dev *edev)
+{
+ return edev->pdata->quirks & EEPROM_93XX46_QUIRK_INSTRUCTION_LENGTH;
+}
+
+static inline bool has_quirk_extra_read_cycle(struct eeprom_93xx46_dev *edev)
+{
+ return edev->pdata->quirks & EEPROM_93XX46_QUIRK_EXTRA_READ_CYCLE;
+}
+
+static int eeprom_93xx46_read(void *priv, unsigned int off,
+ void *val, size_t count)
+{
+ struct eeprom_93xx46_dev *edev = priv;
+ char *buf = val;
+ int err = 0;
+ int bits;
+
+ if (unlikely(off >= edev->size))
+ return 0;
+ if ((off + count) > edev->size)
+ count = edev->size - off;
+ if (unlikely(!count))
+ return count;
+
+ mutex_lock(&edev->lock);
+
+ if (edev->pdata->prepare)
+ edev->pdata->prepare(edev);
+
+ /* The opcode in front of the address is three bits. */
+ bits = edev->addrlen + 3;
+
+ while (count) {
+ struct spi_message m;
+ struct spi_transfer t[2] = { { 0 } };
+ u16 cmd_addr = OP_READ << edev->addrlen;
+ size_t nbytes = count;
+
+ if (edev->pdata->flags & EE_ADDR8) {
+ cmd_addr |= off;
+ if (has_quirk_single_word_read(edev))
+ nbytes = 1;
+ } else {
+ cmd_addr |= (off >> 1);
+ if (has_quirk_single_word_read(edev))
+ nbytes = 2;
+ }
+
+ dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
+ cmd_addr, edev->spi->max_speed_hz);
+
+ if (has_quirk_extra_read_cycle(edev)) {
+ cmd_addr <<= 1;
+ bits += 1;
+ }
+
+ spi_message_init(&m);
+
+ t[0].tx_buf = (char *)&cmd_addr;
+ t[0].len = 2;
+ t[0].bits_per_word = bits;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].rx_buf = buf;
+ t[1].len = count;
+ t[1].bits_per_word = 8;
+ spi_message_add_tail(&t[1], &m);
+
+ err = spi_sync(edev->spi, &m);
+ /* have to wait at least Tcsl ns */
+ ndelay(250);
+
+ if (err) {
+ dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
+ nbytes, (int)off, err);
+ break;
+ }
+
+ buf += nbytes;
+ off += nbytes;
+ count -= nbytes;
+ }
+
+ if (edev->pdata->finish)
+ edev->pdata->finish(edev);
+
+ mutex_unlock(&edev->lock);
+
+ return err;
+}
+
+static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
+{
+ struct spi_message m;
+ struct spi_transfer t;
+ int bits, ret;
+ u16 cmd_addr;
+
+ /* The opcode in front of the address is three bits. */
+ bits = edev->addrlen + 3;
+
+ cmd_addr = OP_START << edev->addrlen;
+ if (edev->pdata->flags & EE_ADDR8)
+ cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
+ else
+ cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
+
+ if (has_quirk_instruction_length(edev)) {
+ cmd_addr <<= 2;
+ bits += 2;
+ }
+
+ dev_dbg(&edev->spi->dev, "ew%s cmd 0x%04x, %d bits\n",
+ is_on ? "en" : "ds", cmd_addr, bits);
+
+ spi_message_init(&m);
+ memset(&t, 0, sizeof(t));
+
+ t.tx_buf = &cmd_addr;
+ t.len = 2;
+ t.bits_per_word = bits;
+ spi_message_add_tail(&t, &m);
+
+ mutex_lock(&edev->lock);
+
+ if (edev->pdata->prepare)
+ edev->pdata->prepare(edev);
+
+ ret = spi_sync(edev->spi, &m);
+ /* have to wait at least Tcsl ns */
+ ndelay(250);
+ if (ret)
+ dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
+ is_on ? "en" : "dis", ret);
+
+ if (edev->pdata->finish)
+ edev->pdata->finish(edev);
+
+ mutex_unlock(&edev->lock);
+ return ret;
+}
+
+static ssize_t
+eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
+ const char *buf, unsigned off)
+{
+ struct spi_message m;
+ struct spi_transfer t[2];
+ int bits, data_len, ret;
+ u16 cmd_addr;
+
+ if (unlikely(off >= edev->size))
+ return -EINVAL;
+
+ /* The opcode in front of the address is three bits. */
+ bits = edev->addrlen + 3;
+
+ cmd_addr = OP_WRITE << edev->addrlen;
+
+ if (edev->pdata->flags & EE_ADDR8) {
+ cmd_addr |= off;
+ data_len = 1;
+ } else {
+ cmd_addr |= (off >> 1);
+ data_len = 2;
+ }
+
+ dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
+
+ spi_message_init(&m);
+ memset(t, 0, sizeof(t));
+
+ t[0].tx_buf = (char *)&cmd_addr;
+ t[0].len = 2;
+ t[0].bits_per_word = bits;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].tx_buf = buf;
+ t[1].len = data_len;
+ t[1].bits_per_word = 8;
+ spi_message_add_tail(&t[1], &m);
+
+ ret = spi_sync(edev->spi, &m);
+ /* have to wait program cycle time Twc ms */
+ mdelay(6);
+ return ret;
+}
+
+static int eeprom_93xx46_write(void *priv, unsigned int off,
+ void *val, size_t count)
+{
+ struct eeprom_93xx46_dev *edev = priv;
+ char *buf = val;
+ int i, ret, step = 1;
+
+ if (unlikely(off >= edev->size))
+ return -EFBIG;
+ if ((off + count) > edev->size)
+ count = edev->size - off;
+ if (unlikely(!count))
+ return count;
+
+ /* only write even number of bytes on 16-bit devices */
+ if (edev->pdata->flags & EE_ADDR16) {
+ step = 2;
+ count &= ~1;
+ }
+
+ /* erase/write enable */
+ ret = eeprom_93xx46_ew(edev, 1);
+ if (ret)
+ return ret;
+
+ mutex_lock(&edev->lock);
+
+ if (edev->pdata->prepare)
+ edev->pdata->prepare(edev);
+
+ for (i = 0; i < count; i += step) {
+ ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
+ if (ret) {
+ dev_err(&edev->spi->dev, "write failed at %d: %d\n",
+ (int)off + i, ret);
+ break;
+ }
+ }
+
+ if (edev->pdata->finish)
+ edev->pdata->finish(edev);
+
+ mutex_unlock(&edev->lock);
+
+ /* erase/write disable */
+ eeprom_93xx46_ew(edev, 0);
+ return ret;
+}
+
+static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
+{
+ struct eeprom_93xx46_platform_data *pd = edev->pdata;
+ struct spi_message m;
+ struct spi_transfer t;
+ int bits, ret;
+ u16 cmd_addr;
+
+ /* The opcode in front of the address is three bits. */
+ bits = edev->addrlen + 3;
+
+ cmd_addr = OP_START << edev->addrlen;
+ if (edev->pdata->flags & EE_ADDR8)
+ cmd_addr |= ADDR_ERAL << 1;
+ else
+ cmd_addr |= ADDR_ERAL;
+
+ if (has_quirk_instruction_length(edev)) {
+ cmd_addr <<= 2;
+ bits += 2;
+ }
+
+ dev_dbg(&edev->spi->dev, "eral cmd 0x%04x, %d bits\n", cmd_addr, bits);
+
+ spi_message_init(&m);
+ memset(&t, 0, sizeof(t));
+
+ t.tx_buf = &cmd_addr;
+ t.len = 2;
+ t.bits_per_word = bits;
+ spi_message_add_tail(&t, &m);
+
+ mutex_lock(&edev->lock);
+
+ if (edev->pdata->prepare)
+ edev->pdata->prepare(edev);
+
+ ret = spi_sync(edev->spi, &m);
+ if (ret)
+ dev_err(&edev->spi->dev, "erase error %d\n", ret);
+ /* have to wait erase cycle time Tec ms */
+ mdelay(6);
+
+ if (pd->finish)
+ pd->finish(edev);
+
+ mutex_unlock(&edev->lock);
+ return ret;
+}
+
+static ssize_t eeprom_93xx46_store_erase(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
+ int erase = 0, ret;
+
+ sscanf(buf, "%d", &erase);
+ if (erase) {
+ ret = eeprom_93xx46_ew(edev, 1);
+ if (ret)
+ return ret;
+ ret = eeprom_93xx46_eral(edev);
+ if (ret)
+ return ret;
+ ret = eeprom_93xx46_ew(edev, 0);
+ if (ret)
+ return ret;
+ }
+ return count;
+}
+static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
+
+static void select_assert(void *context)
+{
+ struct eeprom_93xx46_dev *edev = context;
+
+ gpiod_set_value_cansleep(edev->pdata->select, 1);
+}
+
+static void select_deassert(void *context)
+{
+ struct eeprom_93xx46_dev *edev = context;
+
+ gpiod_set_value_cansleep(edev->pdata->select, 0);
+}
+
+static const struct of_device_id eeprom_93xx46_of_table[] = {
+ { .compatible = "eeprom-93xx46", .data = &at93c46_data, },
+ { .compatible = "atmel,at93c46", .data = &at93c46_data, },
+ { .compatible = "atmel,at93c46d", .data = &atmel_at93c46d_data, },
+ { .compatible = "atmel,at93c56", .data = &at93c56_data, },
+ { .compatible = "atmel,at93c66", .data = &at93c66_data, },
+ { .compatible = "microchip,93lc46b", .data = &microchip_93lc46b_data, },
+ {}
+};
+MODULE_DEVICE_TABLE(of, eeprom_93xx46_of_table);
+
+static const struct spi_device_id eeprom_93xx46_spi_ids[] = {
+ { .name = "eeprom-93xx46",
+ .driver_data = (kernel_ulong_t)&at93c46_data, },
+ { .name = "at93c46",
+ .driver_data = (kernel_ulong_t)&at93c46_data, },
+ { .name = "at93c46d",
+ .driver_data = (kernel_ulong_t)&atmel_at93c46d_data, },
+ { .name = "at93c56",
+ .driver_data = (kernel_ulong_t)&at93c56_data, },
+ { .name = "at93c66",
+ .driver_data = (kernel_ulong_t)&at93c66_data, },
+ { .name = "93lc46b",
+ .driver_data = (kernel_ulong_t)&microchip_93lc46b_data, },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, eeprom_93xx46_spi_ids);
+
+static int eeprom_93xx46_probe_dt(struct spi_device *spi)
+{
+ const struct of_device_id *of_id =
+ of_match_device(eeprom_93xx46_of_table, &spi->dev);
+ struct device_node *np = spi->dev.of_node;
+ struct eeprom_93xx46_platform_data *pd;
+ u32 tmp;
+ int ret;
+
+ pd = devm_kzalloc(&spi->dev, sizeof(*pd), GFP_KERNEL);
+ if (!pd)
+ return -ENOMEM;
+
+ ret = of_property_read_u32(np, "data-size", &tmp);
+ if (ret < 0) {
+ dev_err(&spi->dev, "data-size property not found\n");
+ return ret;
+ }
+
+ if (tmp == 8) {
+ pd->flags |= EE_ADDR8;
+ } else if (tmp == 16) {
+ pd->flags |= EE_ADDR16;
+ } else {
+ dev_err(&spi->dev, "invalid data-size (%d)\n", tmp);
+ return -EINVAL;
+ }
+
+ if (of_property_read_bool(np, "read-only"))
+ pd->flags |= EE_READONLY;
+
+ pd->select = devm_gpiod_get_optional(&spi->dev, "select",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(pd->select))
+ return PTR_ERR(pd->select);
+
+ pd->prepare = select_assert;
+ pd->finish = select_deassert;
+ gpiod_direction_output(pd->select, 0);
+
+ if (of_id->data) {
+ const struct eeprom_93xx46_devtype_data *data = of_id->data;
+
+ pd->quirks = data->quirks;
+ pd->flags |= data->flags;
+ }
+
+ spi->dev.platform_data = pd;
+
+ return 0;
+}
+
+static int eeprom_93xx46_probe(struct spi_device *spi)
+{
+ struct eeprom_93xx46_platform_data *pd;
+ struct eeprom_93xx46_dev *edev;
+ int err;
+
+ if (spi->dev.of_node) {
+ err = eeprom_93xx46_probe_dt(spi);
+ if (err < 0)
+ return err;
+ }
+
+ pd = spi->dev.platform_data;
+ if (!pd) {
+ dev_err(&spi->dev, "missing platform data\n");
+ return -ENODEV;
+ }
+
+ edev = devm_kzalloc(&spi->dev, sizeof(*edev), GFP_KERNEL);
+ if (!edev)
+ return -ENOMEM;
+
+ if (pd->flags & EE_SIZE1K)
+ edev->size = 128;
+ else if (pd->flags & EE_SIZE2K)
+ edev->size = 256;
+ else if (pd->flags & EE_SIZE4K)
+ edev->size = 512;
+ else {
+ dev_err(&spi->dev, "unspecified size\n");
+ return -EINVAL;
+ }
+
+ if (pd->flags & EE_ADDR8)
+ edev->addrlen = ilog2(edev->size);
+ else if (pd->flags & EE_ADDR16)
+ edev->addrlen = ilog2(edev->size) - 1;
+ else {
+ dev_err(&spi->dev, "unspecified address type\n");
+ return -EINVAL;
+ }
+
+ mutex_init(&edev->lock);
+
+ edev->spi = spi;
+ edev->pdata = pd;
+
+ edev->nvmem_config.type = NVMEM_TYPE_EEPROM;
+ edev->nvmem_config.name = dev_name(&spi->dev);
+ edev->nvmem_config.dev = &spi->dev;
+ edev->nvmem_config.read_only = pd->flags & EE_READONLY;
+ edev->nvmem_config.root_only = true;
+ edev->nvmem_config.owner = THIS_MODULE;
+ edev->nvmem_config.compat = true;
+ edev->nvmem_config.base_dev = &spi->dev;
+ edev->nvmem_config.reg_read = eeprom_93xx46_read;
+ edev->nvmem_config.reg_write = eeprom_93xx46_write;
+ edev->nvmem_config.priv = edev;
+ edev->nvmem_config.stride = 4;
+ edev->nvmem_config.word_size = 1;
+ edev->nvmem_config.size = edev->size;
+
+ edev->nvmem = devm_nvmem_register(&spi->dev, &edev->nvmem_config);
+ if (IS_ERR(edev->nvmem))
+ return PTR_ERR(edev->nvmem);
+
+ dev_info(&spi->dev, "%d-bit eeprom containing %d bytes %s\n",
+ (pd->flags & EE_ADDR8) ? 8 : 16,
+ edev->size,
+ (pd->flags & EE_READONLY) ? "(readonly)" : "");
+
+ if (!(pd->flags & EE_READONLY)) {
+ if (device_create_file(&spi->dev, &dev_attr_erase))
+ dev_err(&spi->dev, "can't create erase interface\n");
+ }
+
+ spi_set_drvdata(spi, edev);
+ return 0;
+}
+
+static void eeprom_93xx46_remove(struct spi_device *spi)
+{
+ struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);
+
+ if (!(edev->pdata->flags & EE_READONLY))
+ device_remove_file(&spi->dev, &dev_attr_erase);
+}
+
+static struct spi_driver eeprom_93xx46_driver = {
+ .driver = {
+ .name = "93xx46",
+ .of_match_table = of_match_ptr(eeprom_93xx46_of_table),
+ },
+ .probe = eeprom_93xx46_probe,
+ .remove = eeprom_93xx46_remove,
+ .id_table = eeprom_93xx46_spi_ids,
+};
+
+module_spi_driver(eeprom_93xx46_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
+MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
+MODULE_ALIAS("spi:93xx46");
+MODULE_ALIAS("spi:eeprom-93xx46");
+MODULE_ALIAS("spi:93lc46b");
diff --git a/drivers/misc/eeprom/idt_89hpesx.c b/drivers/misc/eeprom/idt_89hpesx.c
new file mode 100644
index 000000000..367054e0c
--- /dev/null
+++ b/drivers/misc/eeprom/idt_89hpesx.c
@@ -0,0 +1,1597 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2016 T-Platforms. All Rights Reserved.
+ *
+ * IDT PCIe-switch NTB Linux driver
+ *
+ * Contact Information:
+ * Serge Semin <fancer.lancer@gmail.com>, <Sergey.Semin@t-platforms.ru>
+ */
+/*
+ * NOTE of the IDT 89HPESx SMBus-slave interface driver
+ * This driver primarily is developed to have an access to EEPROM device of
+ * IDT PCIe-switches. IDT provides a simple SMBus interface to perform IO-
+ * operations from/to EEPROM, which is located at private (so called Master)
+ * SMBus of switches. Using that interface this the driver creates a simple
+ * binary sysfs-file in the device directory:
+ * /sys/bus/i2c/devices/<bus>-<devaddr>/eeprom
+ * In case if read-only flag is specified in the dts-node of device desription,
+ * User-space applications won't be able to write to the EEPROM sysfs-node.
+ * Additionally IDT 89HPESx SMBus interface has an ability to write/read
+ * data of device CSRs. This driver exposes debugf-file to perform simple IO
+ * operations using that ability for just basic debug purpose. Particularly
+ * next file is created in the specific debugfs-directory:
+ * /sys/kernel/debug/idt_csr/
+ * Format of the debugfs-node is:
+ * $ cat /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
+ * <CSR address>:<CSR value>
+ * So reading the content of the file gives current CSR address and it value.
+ * If User-space application wishes to change current CSR address,
+ * it can just write a proper value to the sysfs-file:
+ * $ echo "<CSR address>" > /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>
+ * If it wants to change the CSR value as well, the format of the write
+ * operation is:
+ * $ echo "<CSR address>:<CSR value>" > \
+ * /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>;
+ * CSR address and value can be any of hexadecimal, decimal or octal format.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/sysfs.h>
+#include <linux/debugfs.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/i2c.h>
+#include <linux/pci_ids.h>
+#include <linux/delay.h>
+
+#define IDT_NAME "89hpesx"
+#define IDT_89HPESX_DESC "IDT 89HPESx SMBus-slave interface driver"
+#define IDT_89HPESX_VER "1.0"
+
+MODULE_DESCRIPTION(IDT_89HPESX_DESC);
+MODULE_VERSION(IDT_89HPESX_VER);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("T-platforms");
+
+/*
+ * csr_dbgdir - CSR read/write operations Debugfs directory
+ */
+static struct dentry *csr_dbgdir;
+
+/*
+ * struct idt_89hpesx_dev - IDT 89HPESx device data structure
+ * @eesize: Size of EEPROM in bytes (calculated from "idt,eecompatible")
+ * @eero: EEPROM Read-only flag
+ * @eeaddr: EEPROM custom address
+ *
+ * @inieecmd: Initial cmd value for EEPROM read/write operations
+ * @inicsrcmd: Initial cmd value for CSR read/write operations
+ * @iniccode: Initialial command code value for IO-operations
+ *
+ * @csr: CSR address to perform read operation
+ *
+ * @smb_write: SMBus write method
+ * @smb_read: SMBus read method
+ * @smb_mtx: SMBus mutex
+ *
+ * @client: i2c client used to perform IO operations
+ *
+ * @ee_file: EEPROM read/write sysfs-file
+ */
+struct idt_smb_seq;
+struct idt_89hpesx_dev {
+ u32 eesize;
+ bool eero;
+ u8 eeaddr;
+
+ u8 inieecmd;
+ u8 inicsrcmd;
+ u8 iniccode;
+
+ u16 csr;
+
+ int (*smb_write)(struct idt_89hpesx_dev *, const struct idt_smb_seq *);
+ int (*smb_read)(struct idt_89hpesx_dev *, struct idt_smb_seq *);
+ struct mutex smb_mtx;
+
+ struct i2c_client *client;
+
+ struct bin_attribute *ee_file;
+ struct dentry *csr_dir;
+};
+
+/*
+ * struct idt_smb_seq - sequence of data to be read/written from/to IDT 89HPESx
+ * @ccode: SMBus command code
+ * @bytecnt: Byte count of operation
+ * @data: Data to by written
+ */
+struct idt_smb_seq {
+ u8 ccode;
+ u8 bytecnt;
+ u8 *data;
+};
+
+/*
+ * struct idt_eeprom_seq - sequence of data to be read/written from/to EEPROM
+ * @cmd: Transaction CMD
+ * @eeaddr: EEPROM custom address
+ * @memaddr: Internal memory address of EEPROM
+ * @data: Data to be written at the memory address
+ */
+struct idt_eeprom_seq {
+ u8 cmd;
+ u8 eeaddr;
+ u16 memaddr;
+ u8 data;
+} __packed;
+
+/*
+ * struct idt_csr_seq - sequence of data to be read/written from/to CSR
+ * @cmd: Transaction CMD
+ * @csraddr: Internal IDT device CSR address
+ * @data: Data to be read/written from/to the CSR address
+ */
+struct idt_csr_seq {
+ u8 cmd;
+ u16 csraddr;
+ u32 data;
+} __packed;
+
+/*
+ * SMBus command code macros
+ * @CCODE_END: Indicates the end of transaction
+ * @CCODE_START: Indicates the start of transaction
+ * @CCODE_CSR: CSR read/write transaction
+ * @CCODE_EEPROM: EEPROM read/write transaction
+ * @CCODE_BYTE: Supplied data has BYTE length
+ * @CCODE_WORD: Supplied data has WORD length
+ * @CCODE_BLOCK: Supplied data has variable length passed in bytecnt
+ * byte right following CCODE byte
+ */
+#define CCODE_END ((u8)0x01)
+#define CCODE_START ((u8)0x02)
+#define CCODE_CSR ((u8)0x00)
+#define CCODE_EEPROM ((u8)0x04)
+#define CCODE_BYTE ((u8)0x00)
+#define CCODE_WORD ((u8)0x20)
+#define CCODE_BLOCK ((u8)0x40)
+#define CCODE_PEC ((u8)0x80)
+
+/*
+ * EEPROM command macros
+ * @EEPROM_OP_WRITE: EEPROM write operation
+ * @EEPROM_OP_READ: EEPROM read operation
+ * @EEPROM_USA: Use specified address of EEPROM
+ * @EEPROM_NAERR: EEPROM device is not ready to respond
+ * @EEPROM_LAERR: EEPROM arbitration loss error
+ * @EEPROM_MSS: EEPROM misplace start & stop bits error
+ * @EEPROM_WR_CNT: Bytes count to perform write operation
+ * @EEPROM_WRRD_CNT: Bytes count to write before reading
+ * @EEPROM_RD_CNT: Bytes count to perform read operation
+ * @EEPROM_DEF_SIZE: Fall back size of EEPROM
+ * @EEPROM_DEF_ADDR: Defatul EEPROM address
+ * @EEPROM_TOUT: Timeout before retry read operation if eeprom is busy
+ */
+#define EEPROM_OP_WRITE ((u8)0x00)
+#define EEPROM_OP_READ ((u8)0x01)
+#define EEPROM_USA ((u8)0x02)
+#define EEPROM_NAERR ((u8)0x08)
+#define EEPROM_LAERR ((u8)0x10)
+#define EEPROM_MSS ((u8)0x20)
+#define EEPROM_WR_CNT ((u8)5)
+#define EEPROM_WRRD_CNT ((u8)4)
+#define EEPROM_RD_CNT ((u8)5)
+#define EEPROM_DEF_SIZE ((u16)4096)
+#define EEPROM_DEF_ADDR ((u8)0x50)
+#define EEPROM_TOUT (100)
+
+/*
+ * CSR command macros
+ * @CSR_DWE: Enable all four bytes of the operation
+ * @CSR_OP_WRITE: CSR write operation
+ * @CSR_OP_READ: CSR read operation
+ * @CSR_RERR: Read operation error
+ * @CSR_WERR: Write operation error
+ * @CSR_WR_CNT: Bytes count to perform write operation
+ * @CSR_WRRD_CNT: Bytes count to write before reading
+ * @CSR_RD_CNT: Bytes count to perform read operation
+ * @CSR_MAX: Maximum CSR address
+ * @CSR_DEF: Default CSR address
+ * @CSR_REAL_ADDR: CSR real unshifted address
+ */
+#define CSR_DWE ((u8)0x0F)
+#define CSR_OP_WRITE ((u8)0x00)
+#define CSR_OP_READ ((u8)0x10)
+#define CSR_RERR ((u8)0x40)
+#define CSR_WERR ((u8)0x80)
+#define CSR_WR_CNT ((u8)7)
+#define CSR_WRRD_CNT ((u8)3)
+#define CSR_RD_CNT ((u8)7)
+#define CSR_MAX ((u32)0x3FFFF)
+#define CSR_DEF ((u16)0x0000)
+#define CSR_REAL_ADDR(val) ((unsigned int)val << 2)
+
+/*
+ * IDT 89HPESx basic register
+ * @IDT_VIDDID_CSR: PCIe VID and DID of IDT 89HPESx
+ * @IDT_VID_MASK: Mask of VID
+ */
+#define IDT_VIDDID_CSR ((u32)0x0000)
+#define IDT_VID_MASK ((u32)0xFFFF)
+
+/*
+ * IDT 89HPESx can send NACK when new command is sent before previous one
+ * fininshed execution. In this case driver retries operation
+ * certain times.
+ * @RETRY_CNT: Number of retries before giving up and fail
+ * @idt_smb_safe: Generate a retry loop on corresponding SMBus method
+ */
+#define RETRY_CNT (128)
+#define idt_smb_safe(ops, args...) ({ \
+ int __retry = RETRY_CNT; \
+ s32 __sts; \
+ do { \
+ __sts = i2c_smbus_ ## ops ## _data(args); \
+ } while (__retry-- && __sts < 0); \
+ __sts; \
+})
+
+/*===========================================================================
+ * i2c bus level IO-operations
+ *===========================================================================
+ */
+
+/*
+ * idt_smb_write_byte() - SMBus write method when I2C_SMBUS_BYTE_DATA operation
+ * is only available
+ * @pdev: Pointer to the driver data
+ * @seq: Sequence of data to be written
+ */
+static int idt_smb_write_byte(struct idt_89hpesx_dev *pdev,
+ const struct idt_smb_seq *seq)
+{
+ s32 sts;
+ u8 ccode;
+ int idx;
+
+ /* Loop over the supplied data sending byte one-by-one */
+ for (idx = 0; idx < seq->bytecnt; idx++) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BYTE;
+ if (idx == 0)
+ ccode |= CCODE_START;
+ if (idx == seq->bytecnt - 1)
+ ccode |= CCODE_END;
+
+ /* Send data to the device */
+ sts = idt_smb_safe(write_byte, pdev->client, ccode,
+ seq->data[idx]);
+ if (sts != 0)
+ return (int)sts;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_smb_read_byte() - SMBus read method when I2C_SMBUS_BYTE_DATA operation
+ * is only available
+ * @pdev: Pointer to the driver data
+ * @seq: Buffer to read data to
+ */
+static int idt_smb_read_byte(struct idt_89hpesx_dev *pdev,
+ struct idt_smb_seq *seq)
+{
+ s32 sts;
+ u8 ccode;
+ int idx;
+
+ /* Loop over the supplied buffer receiving byte one-by-one */
+ for (idx = 0; idx < seq->bytecnt; idx++) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BYTE;
+ if (idx == 0)
+ ccode |= CCODE_START;
+ if (idx == seq->bytecnt - 1)
+ ccode |= CCODE_END;
+
+ /* Read data from the device */
+ sts = idt_smb_safe(read_byte, pdev->client, ccode);
+ if (sts < 0)
+ return (int)sts;
+
+ seq->data[idx] = (u8)sts;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_smb_write_word() - SMBus write method when I2C_SMBUS_BYTE_DATA and
+ * I2C_FUNC_SMBUS_WORD_DATA operations are available
+ * @pdev: Pointer to the driver data
+ * @seq: Sequence of data to be written
+ */
+static int idt_smb_write_word(struct idt_89hpesx_dev *pdev,
+ const struct idt_smb_seq *seq)
+{
+ s32 sts;
+ u8 ccode;
+ int idx, evencnt;
+
+ /* Calculate the even count of data to send */
+ evencnt = seq->bytecnt - (seq->bytecnt % 2);
+
+ /* Loop over the supplied data sending two bytes at a time */
+ for (idx = 0; idx < evencnt; idx += 2) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_WORD;
+ if (idx == 0)
+ ccode |= CCODE_START;
+ if (idx == evencnt - 2)
+ ccode |= CCODE_END;
+
+ /* Send word data to the device */
+ sts = idt_smb_safe(write_word, pdev->client, ccode,
+ *(u16 *)&seq->data[idx]);
+ if (sts != 0)
+ return (int)sts;
+ }
+
+ /* If there is odd number of bytes then send just one last byte */
+ if (seq->bytecnt != evencnt) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BYTE | CCODE_END;
+ if (idx == 0)
+ ccode |= CCODE_START;
+
+ /* Send byte data to the device */
+ sts = idt_smb_safe(write_byte, pdev->client, ccode,
+ seq->data[idx]);
+ if (sts != 0)
+ return (int)sts;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_smb_read_word() - SMBus read method when I2C_SMBUS_BYTE_DATA and
+ * I2C_FUNC_SMBUS_WORD_DATA operations are available
+ * @pdev: Pointer to the driver data
+ * @seq: Buffer to read data to
+ */
+static int idt_smb_read_word(struct idt_89hpesx_dev *pdev,
+ struct idt_smb_seq *seq)
+{
+ s32 sts;
+ u8 ccode;
+ int idx, evencnt;
+
+ /* Calculate the even count of data to send */
+ evencnt = seq->bytecnt - (seq->bytecnt % 2);
+
+ /* Loop over the supplied data reading two bytes at a time */
+ for (idx = 0; idx < evencnt; idx += 2) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_WORD;
+ if (idx == 0)
+ ccode |= CCODE_START;
+ if (idx == evencnt - 2)
+ ccode |= CCODE_END;
+
+ /* Read word data from the device */
+ sts = idt_smb_safe(read_word, pdev->client, ccode);
+ if (sts < 0)
+ return (int)sts;
+
+ *(u16 *)&seq->data[idx] = (u16)sts;
+ }
+
+ /* If there is odd number of bytes then receive just one last byte */
+ if (seq->bytecnt != evencnt) {
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BYTE | CCODE_END;
+ if (idx == 0)
+ ccode |= CCODE_START;
+
+ /* Read last data byte from the device */
+ sts = idt_smb_safe(read_byte, pdev->client, ccode);
+ if (sts < 0)
+ return (int)sts;
+
+ seq->data[idx] = (u8)sts;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_smb_write_block() - SMBus write method when I2C_SMBUS_BLOCK_DATA
+ * operation is available
+ * @pdev: Pointer to the driver data
+ * @seq: Sequence of data to be written
+ */
+static int idt_smb_write_block(struct idt_89hpesx_dev *pdev,
+ const struct idt_smb_seq *seq)
+{
+ u8 ccode;
+
+ /* Return error if too much data passed to send */
+ if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
+ return -EINVAL;
+
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
+
+ /* Send block of data to the device */
+ return idt_smb_safe(write_block, pdev->client, ccode, seq->bytecnt,
+ seq->data);
+}
+
+/*
+ * idt_smb_read_block() - SMBus read method when I2C_SMBUS_BLOCK_DATA
+ * operation is available
+ * @pdev: Pointer to the driver data
+ * @seq: Buffer to read data to
+ */
+static int idt_smb_read_block(struct idt_89hpesx_dev *pdev,
+ struct idt_smb_seq *seq)
+{
+ s32 sts;
+ u8 ccode;
+
+ /* Return error if too much data passed to send */
+ if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
+ return -EINVAL;
+
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
+
+ /* Read block of data from the device */
+ sts = idt_smb_safe(read_block, pdev->client, ccode, seq->data);
+ if (sts != seq->bytecnt)
+ return (sts < 0 ? sts : -ENODATA);
+
+ return 0;
+}
+
+/*
+ * idt_smb_write_i2c_block() - SMBus write method when I2C_SMBUS_I2C_BLOCK_DATA
+ * operation is available
+ * @pdev: Pointer to the driver data
+ * @seq: Sequence of data to be written
+ *
+ * NOTE It's usual SMBus write block operation, except the actual data length is
+ * sent as first byte of data
+ */
+static int idt_smb_write_i2c_block(struct idt_89hpesx_dev *pdev,
+ const struct idt_smb_seq *seq)
+{
+ u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
+
+ /* Return error if too much data passed to send */
+ if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
+ return -EINVAL;
+
+ /* Collect the data to send. Length byte must be added prior the data */
+ buf[0] = seq->bytecnt;
+ memcpy(&buf[1], seq->data, seq->bytecnt);
+
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
+
+ /* Send length and block of data to the device */
+ return idt_smb_safe(write_i2c_block, pdev->client, ccode,
+ seq->bytecnt + 1, buf);
+}
+
+/*
+ * idt_smb_read_i2c_block() - SMBus read method when I2C_SMBUS_I2C_BLOCK_DATA
+ * operation is available
+ * @pdev: Pointer to the driver data
+ * @seq: Buffer to read data to
+ *
+ * NOTE It's usual SMBus read block operation, except the actual data length is
+ * retrieved as first byte of data
+ */
+static int idt_smb_read_i2c_block(struct idt_89hpesx_dev *pdev,
+ struct idt_smb_seq *seq)
+{
+ u8 ccode, buf[I2C_SMBUS_BLOCK_MAX + 1];
+ s32 sts;
+
+ /* Return error if too much data passed to send */
+ if (seq->bytecnt > I2C_SMBUS_BLOCK_MAX)
+ return -EINVAL;
+
+ /* Collect the command code byte */
+ ccode = seq->ccode | CCODE_BLOCK | CCODE_START | CCODE_END;
+
+ /* Read length and block of data from the device */
+ sts = idt_smb_safe(read_i2c_block, pdev->client, ccode,
+ seq->bytecnt + 1, buf);
+ if (sts != seq->bytecnt + 1)
+ return (sts < 0 ? sts : -ENODATA);
+ if (buf[0] != seq->bytecnt)
+ return -ENODATA;
+
+ /* Copy retrieved data to the output data buffer */
+ memcpy(seq->data, &buf[1], seq->bytecnt);
+
+ return 0;
+}
+
+/*===========================================================================
+ * EEPROM IO-operations
+ *===========================================================================
+ */
+
+/*
+ * idt_eeprom_read_byte() - read just one byte from EEPROM
+ * @pdev: Pointer to the driver data
+ * @memaddr: Start EEPROM memory address
+ * @data: Data to be written to EEPROM
+ */
+static int idt_eeprom_read_byte(struct idt_89hpesx_dev *pdev, u16 memaddr,
+ u8 *data)
+{
+ struct device *dev = &pdev->client->dev;
+ struct idt_eeprom_seq eeseq;
+ struct idt_smb_seq smbseq;
+ int ret, retry;
+
+ /* Initialize SMBus sequence fields */
+ smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
+ smbseq.data = (u8 *)&eeseq;
+
+ /*
+ * Sometimes EEPROM may respond with NACK if it's busy with previous
+ * operation, so we need to perform a few attempts of read cycle
+ */
+ retry = RETRY_CNT;
+ do {
+ /* Send EEPROM memory address to read data from */
+ smbseq.bytecnt = EEPROM_WRRD_CNT;
+ eeseq.cmd = pdev->inieecmd | EEPROM_OP_READ;
+ eeseq.eeaddr = pdev->eeaddr;
+ eeseq.memaddr = cpu_to_le16(memaddr);
+ ret = pdev->smb_write(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to init eeprom addr 0x%02x",
+ memaddr);
+ break;
+ }
+
+ /* Perform read operation */
+ smbseq.bytecnt = EEPROM_RD_CNT;
+ ret = pdev->smb_read(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to read eeprom data 0x%02x",
+ memaddr);
+ break;
+ }
+
+ /* Restart read operation if the device is busy */
+ if (retry && (eeseq.cmd & EEPROM_NAERR)) {
+ dev_dbg(dev, "EEPROM busy, retry reading after %d ms",
+ EEPROM_TOUT);
+ msleep(EEPROM_TOUT);
+ continue;
+ }
+
+ /* Check whether IDT successfully read data from EEPROM */
+ if (eeseq.cmd & (EEPROM_NAERR | EEPROM_LAERR | EEPROM_MSS)) {
+ dev_err(dev,
+ "Communication with eeprom failed, cmd 0x%hhx",
+ eeseq.cmd);
+ ret = -EREMOTEIO;
+ break;
+ }
+
+ /* Save retrieved data and exit the loop */
+ *data = eeseq.data;
+ break;
+ } while (retry--);
+
+ /* Return the status of operation */
+ return ret;
+}
+
+/*
+ * idt_eeprom_write() - EEPROM write operation
+ * @pdev: Pointer to the driver data
+ * @memaddr: Start EEPROM memory address
+ * @len: Length of data to be written
+ * @data: Data to be written to EEPROM
+ */
+static int idt_eeprom_write(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
+ const u8 *data)
+{
+ struct device *dev = &pdev->client->dev;
+ struct idt_eeprom_seq eeseq;
+ struct idt_smb_seq smbseq;
+ int ret;
+ u16 idx;
+
+ /* Initialize SMBus sequence fields */
+ smbseq.ccode = pdev->iniccode | CCODE_EEPROM;
+ smbseq.data = (u8 *)&eeseq;
+
+ /* Send data byte-by-byte, checking if it is successfully written */
+ for (idx = 0; idx < len; idx++, memaddr++) {
+ /* Lock IDT SMBus device */
+ mutex_lock(&pdev->smb_mtx);
+
+ /* Perform write operation */
+ smbseq.bytecnt = EEPROM_WR_CNT;
+ eeseq.cmd = pdev->inieecmd | EEPROM_OP_WRITE;
+ eeseq.eeaddr = pdev->eeaddr;
+ eeseq.memaddr = cpu_to_le16(memaddr);
+ eeseq.data = data[idx];
+ ret = pdev->smb_write(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev,
+ "Failed to write 0x%04hx:0x%02hhx to eeprom",
+ memaddr, data[idx]);
+ goto err_mutex_unlock;
+ }
+
+ /*
+ * Check whether the data is successfully written by reading
+ * from the same EEPROM memory address.
+ */
+ eeseq.data = ~data[idx];
+ ret = idt_eeprom_read_byte(pdev, memaddr, &eeseq.data);
+ if (ret != 0)
+ goto err_mutex_unlock;
+
+ /* Check whether the read byte is the same as written one */
+ if (eeseq.data != data[idx]) {
+ dev_err(dev, "Values don't match 0x%02hhx != 0x%02hhx",
+ eeseq.data, data[idx]);
+ ret = -EREMOTEIO;
+ goto err_mutex_unlock;
+ }
+
+ /* Unlock IDT SMBus device */
+err_mutex_unlock:
+ mutex_unlock(&pdev->smb_mtx);
+ if (ret != 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_eeprom_read() - EEPROM read operation
+ * @pdev: Pointer to the driver data
+ * @memaddr: Start EEPROM memory address
+ * @len: Length of data to read
+ * @buf: Buffer to read data to
+ */
+static int idt_eeprom_read(struct idt_89hpesx_dev *pdev, u16 memaddr, u16 len,
+ u8 *buf)
+{
+ int ret;
+ u16 idx;
+
+ /* Read data byte-by-byte, retrying if it wasn't successful */
+ for (idx = 0; idx < len; idx++, memaddr++) {
+ /* Lock IDT SMBus device */
+ mutex_lock(&pdev->smb_mtx);
+
+ /* Just read the byte to the buffer */
+ ret = idt_eeprom_read_byte(pdev, memaddr, &buf[idx]);
+
+ /* Unlock IDT SMBus device */
+ mutex_unlock(&pdev->smb_mtx);
+
+ /* Return error if read operation failed */
+ if (ret != 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+/*===========================================================================
+ * CSR IO-operations
+ *===========================================================================
+ */
+
+/*
+ * idt_csr_write() - CSR write operation
+ * @pdev: Pointer to the driver data
+ * @csraddr: CSR address (with no two LS bits)
+ * @data: Data to be written to CSR
+ */
+static int idt_csr_write(struct idt_89hpesx_dev *pdev, u16 csraddr,
+ const u32 data)
+{
+ struct device *dev = &pdev->client->dev;
+ struct idt_csr_seq csrseq;
+ struct idt_smb_seq smbseq;
+ int ret;
+
+ /* Initialize SMBus sequence fields */
+ smbseq.ccode = pdev->iniccode | CCODE_CSR;
+ smbseq.data = (u8 *)&csrseq;
+
+ /* Lock IDT SMBus device */
+ mutex_lock(&pdev->smb_mtx);
+
+ /* Perform write operation */
+ smbseq.bytecnt = CSR_WR_CNT;
+ csrseq.cmd = pdev->inicsrcmd | CSR_OP_WRITE;
+ csrseq.csraddr = cpu_to_le16(csraddr);
+ csrseq.data = cpu_to_le32(data);
+ ret = pdev->smb_write(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to write 0x%04x: 0x%04x to csr",
+ CSR_REAL_ADDR(csraddr), data);
+ goto err_mutex_unlock;
+ }
+
+ /* Send CSR address to read data from */
+ smbseq.bytecnt = CSR_WRRD_CNT;
+ csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
+ ret = pdev->smb_write(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to init csr address 0x%04x",
+ CSR_REAL_ADDR(csraddr));
+ goto err_mutex_unlock;
+ }
+
+ /* Perform read operation */
+ smbseq.bytecnt = CSR_RD_CNT;
+ ret = pdev->smb_read(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to read csr 0x%04x",
+ CSR_REAL_ADDR(csraddr));
+ goto err_mutex_unlock;
+ }
+
+ /* Check whether IDT successfully retrieved CSR data */
+ if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
+ dev_err(dev, "IDT failed to perform CSR r/w");
+ ret = -EREMOTEIO;
+ goto err_mutex_unlock;
+ }
+
+ /* Unlock IDT SMBus device */
+err_mutex_unlock:
+ mutex_unlock(&pdev->smb_mtx);
+
+ return ret;
+}
+
+/*
+ * idt_csr_read() - CSR read operation
+ * @pdev: Pointer to the driver data
+ * @csraddr: CSR address (with no two LS bits)
+ * @data: Data to be written to CSR
+ */
+static int idt_csr_read(struct idt_89hpesx_dev *pdev, u16 csraddr, u32 *data)
+{
+ struct device *dev = &pdev->client->dev;
+ struct idt_csr_seq csrseq;
+ struct idt_smb_seq smbseq;
+ int ret;
+
+ /* Initialize SMBus sequence fields */
+ smbseq.ccode = pdev->iniccode | CCODE_CSR;
+ smbseq.data = (u8 *)&csrseq;
+
+ /* Lock IDT SMBus device */
+ mutex_lock(&pdev->smb_mtx);
+
+ /* Send CSR register address before reading it */
+ smbseq.bytecnt = CSR_WRRD_CNT;
+ csrseq.cmd = pdev->inicsrcmd | CSR_OP_READ;
+ csrseq.csraddr = cpu_to_le16(csraddr);
+ ret = pdev->smb_write(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to init csr address 0x%04x",
+ CSR_REAL_ADDR(csraddr));
+ goto err_mutex_unlock;
+ }
+
+ /* Perform read operation */
+ smbseq.bytecnt = CSR_RD_CNT;
+ ret = pdev->smb_read(pdev, &smbseq);
+ if (ret != 0) {
+ dev_err(dev, "Failed to read csr 0x%04x",
+ CSR_REAL_ADDR(csraddr));
+ goto err_mutex_unlock;
+ }
+
+ /* Check whether IDT successfully retrieved CSR data */
+ if (csrseq.cmd & (CSR_RERR | CSR_WERR)) {
+ dev_err(dev, "IDT failed to perform CSR r/w");
+ ret = -EREMOTEIO;
+ goto err_mutex_unlock;
+ }
+
+ /* Save data retrieved from IDT */
+ *data = le32_to_cpu(csrseq.data);
+
+ /* Unlock IDT SMBus device */
+err_mutex_unlock:
+ mutex_unlock(&pdev->smb_mtx);
+
+ return ret;
+}
+
+/*===========================================================================
+ * Sysfs/debugfs-nodes IO-operations
+ *===========================================================================
+ */
+
+/*
+ * eeprom_write() - EEPROM sysfs-node write callback
+ * @filep: Pointer to the file system node
+ * @kobj: Pointer to the kernel object related to the sysfs-node
+ * @attr: Attributes of the file
+ * @buf: Buffer to write data to
+ * @off: Offset at which data should be written to
+ * @count: Number of bytes to write
+ */
+static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct idt_89hpesx_dev *pdev;
+ int ret;
+
+ /* Retrieve driver data */
+ pdev = dev_get_drvdata(kobj_to_dev(kobj));
+
+ /* Perform EEPROM write operation */
+ ret = idt_eeprom_write(pdev, (u16)off, (u16)count, (u8 *)buf);
+ return (ret != 0 ? ret : count);
+}
+
+/*
+ * eeprom_read() - EEPROM sysfs-node read callback
+ * @filep: Pointer to the file system node
+ * @kobj: Pointer to the kernel object related to the sysfs-node
+ * @attr: Attributes of the file
+ * @buf: Buffer to write data to
+ * @off: Offset at which data should be written to
+ * @count: Number of bytes to write
+ */
+static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct idt_89hpesx_dev *pdev;
+ int ret;
+
+ /* Retrieve driver data */
+ pdev = dev_get_drvdata(kobj_to_dev(kobj));
+
+ /* Perform EEPROM read operation */
+ ret = idt_eeprom_read(pdev, (u16)off, (u16)count, (u8 *)buf);
+ return (ret != 0 ? ret : count);
+}
+
+/*
+ * idt_dbgfs_csr_write() - CSR debugfs-node write callback
+ * @filep: Pointer to the file system file descriptor
+ * @buf: Buffer to read data from
+ * @count: Size of the buffer
+ * @offp: Offset within the file
+ *
+ * It accepts either "0x<reg addr>:0x<value>" for saving register address
+ * and writing value to specified DWORD register or "0x<reg addr>" for
+ * just saving register address in order to perform next read operation.
+ *
+ * WARNING No spaces are allowed. Incoming string must be strictly formated as:
+ * "<reg addr>:<value>". Register address must be aligned within 4 bytes
+ * (one DWORD).
+ */
+static ssize_t idt_dbgfs_csr_write(struct file *filep, const char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct idt_89hpesx_dev *pdev = filep->private_data;
+ char *colon_ch, *csraddr_str, *csrval_str;
+ int ret, csraddr_len;
+ u32 csraddr, csrval;
+ char *buf;
+
+ if (*offp)
+ return 0;
+
+ /* Copy data from User-space */
+ buf = kmalloc(count + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (copy_from_user(buf, ubuf, count)) {
+ ret = -EFAULT;
+ goto free_buf;
+ }
+ buf[count] = 0;
+
+ /* Find position of colon in the buffer */
+ colon_ch = strnchr(buf, count, ':');
+
+ /*
+ * If there is colon passed then new CSR value should be parsed as
+ * well, so allocate buffer for CSR address substring.
+ * If no colon is found, then string must have just one number with
+ * no new CSR value
+ */
+ if (colon_ch != NULL) {
+ csraddr_len = colon_ch - buf;
+ csraddr_str =
+ kmalloc(csraddr_len + 1, GFP_KERNEL);
+ if (csraddr_str == NULL) {
+ ret = -ENOMEM;
+ goto free_buf;
+ }
+ /* Copy the register address to the substring buffer */
+ strncpy(csraddr_str, buf, csraddr_len);
+ csraddr_str[csraddr_len] = '\0';
+ /* Register value must follow the colon */
+ csrval_str = colon_ch + 1;
+ } else /* if (str_colon == NULL) */ {
+ csraddr_str = (char *)buf; /* Just to shut warning up */
+ csraddr_len = strnlen(csraddr_str, count);
+ csrval_str = NULL;
+ }
+
+ /* Convert CSR address to u32 value */
+ ret = kstrtou32(csraddr_str, 0, &csraddr);
+ if (ret != 0)
+ goto free_csraddr_str;
+
+ /* Check whether passed register address is valid */
+ if (csraddr > CSR_MAX || !IS_ALIGNED(csraddr, SZ_4)) {
+ ret = -EINVAL;
+ goto free_csraddr_str;
+ }
+
+ /* Shift register address to the right so to have u16 address */
+ pdev->csr = (csraddr >> 2);
+
+ /* Parse new CSR value and send it to IDT, if colon has been found */
+ if (colon_ch != NULL) {
+ ret = kstrtou32(csrval_str, 0, &csrval);
+ if (ret != 0)
+ goto free_csraddr_str;
+
+ ret = idt_csr_write(pdev, pdev->csr, csrval);
+ if (ret != 0)
+ goto free_csraddr_str;
+ }
+
+ /* Free memory only if colon has been found */
+free_csraddr_str:
+ if (colon_ch != NULL)
+ kfree(csraddr_str);
+
+ /* Free buffer allocated for data retrieved from User-space */
+free_buf:
+ kfree(buf);
+
+ return (ret != 0 ? ret : count);
+}
+
+/*
+ * idt_dbgfs_csr_read() - CSR debugfs-node read callback
+ * @filep: Pointer to the file system file descriptor
+ * @buf: Buffer to write data to
+ * @count: Size of the buffer
+ * @offp: Offset within the file
+ *
+ * It just prints the pair "0x<reg addr>:0x<value>" to passed buffer.
+ */
+#define CSRBUF_SIZE ((size_t)32)
+static ssize_t idt_dbgfs_csr_read(struct file *filep, char __user *ubuf,
+ size_t count, loff_t *offp)
+{
+ struct idt_89hpesx_dev *pdev = filep->private_data;
+ u32 csraddr, csrval;
+ char buf[CSRBUF_SIZE];
+ int ret, size;
+
+ /* Perform CSR read operation */
+ ret = idt_csr_read(pdev, pdev->csr, &csrval);
+ if (ret != 0)
+ return ret;
+
+ /* Shift register address to the left so to have real address */
+ csraddr = ((u32)pdev->csr << 2);
+
+ /* Print the "0x<reg addr>:0x<value>" to buffer */
+ size = snprintf(buf, CSRBUF_SIZE, "0x%05x:0x%08x\n",
+ (unsigned int)csraddr, (unsigned int)csrval);
+
+ /* Copy data to User-space */
+ return simple_read_from_buffer(ubuf, count, offp, buf, size);
+}
+
+/*
+ * eeprom_attribute - EEPROM sysfs-node attributes
+ *
+ * NOTE Size will be changed in compliance with OF node. EEPROM attribute will
+ * be read-only as well if the corresponding flag is specified in OF node.
+ */
+static BIN_ATTR_RW(eeprom, EEPROM_DEF_SIZE);
+
+/*
+ * csr_dbgfs_ops - CSR debugfs-node read/write operations
+ */
+static const struct file_operations csr_dbgfs_ops = {
+ .owner = THIS_MODULE,
+ .open = simple_open,
+ .write = idt_dbgfs_csr_write,
+ .read = idt_dbgfs_csr_read
+};
+
+/*===========================================================================
+ * Driver init/deinit methods
+ *===========================================================================
+ */
+
+/*
+ * idt_set_defval() - disable EEPROM access by default
+ * @pdev: Pointer to the driver data
+ */
+static void idt_set_defval(struct idt_89hpesx_dev *pdev)
+{
+ /* If OF info is missing then use next values */
+ pdev->eesize = 0;
+ pdev->eero = true;
+ pdev->inieecmd = 0;
+ pdev->eeaddr = 0;
+}
+
+static const struct i2c_device_id ee_ids[];
+
+/*
+ * idt_ee_match_id() - check whether the node belongs to compatible EEPROMs
+ */
+static const struct i2c_device_id *idt_ee_match_id(struct fwnode_handle *fwnode)
+{
+ const struct i2c_device_id *id = ee_ids;
+ const char *compatible, *p;
+ char devname[I2C_NAME_SIZE];
+ int ret;
+
+ ret = fwnode_property_read_string(fwnode, "compatible", &compatible);
+ if (ret)
+ return NULL;
+
+ p = strchr(compatible, ',');
+ strscpy(devname, p ? p + 1 : compatible, sizeof(devname));
+ /* Search through the device name */
+ while (id->name[0]) {
+ if (strcmp(devname, id->name) == 0)
+ return id;
+ id++;
+ }
+ return NULL;
+}
+
+/*
+ * idt_get_fw_data() - get IDT i2c-device parameters from device tree
+ * @pdev: Pointer to the driver data
+ */
+static void idt_get_fw_data(struct idt_89hpesx_dev *pdev)
+{
+ struct device *dev = &pdev->client->dev;
+ struct fwnode_handle *fwnode;
+ const struct i2c_device_id *ee_id = NULL;
+ u32 eeprom_addr;
+ int ret;
+
+ device_for_each_child_node(dev, fwnode) {
+ ee_id = idt_ee_match_id(fwnode);
+ if (ee_id)
+ break;
+
+ dev_warn(dev, "Skip unsupported EEPROM device %pfw\n", fwnode);
+ }
+
+ /* If there is no fwnode EEPROM device, then set zero size */
+ if (!ee_id) {
+ dev_warn(dev, "No fwnode, EEPROM access disabled");
+ idt_set_defval(pdev);
+ return;
+ }
+
+ /* Retrieve EEPROM size */
+ pdev->eesize = (u32)ee_id->driver_data;
+
+ /* Get custom EEPROM address from 'reg' attribute */
+ ret = fwnode_property_read_u32(fwnode, "reg", &eeprom_addr);
+ if (ret || (eeprom_addr == 0)) {
+ dev_warn(dev, "No EEPROM reg found, use default address 0x%x",
+ EEPROM_DEF_ADDR);
+ pdev->inieecmd = 0;
+ pdev->eeaddr = EEPROM_DEF_ADDR << 1;
+ } else {
+ pdev->inieecmd = EEPROM_USA;
+ pdev->eeaddr = eeprom_addr << 1;
+ }
+
+ /* Check EEPROM 'read-only' flag */
+ if (fwnode_property_read_bool(fwnode, "read-only"))
+ pdev->eero = true;
+ else /* if (!fwnode_property_read_bool(node, "read-only")) */
+ pdev->eero = false;
+
+ fwnode_handle_put(fwnode);
+ dev_info(dev, "EEPROM of %d bytes found by 0x%x",
+ pdev->eesize, pdev->eeaddr);
+}
+
+/*
+ * idt_create_pdev() - create and init data structure of the driver
+ * @client: i2c client of IDT PCIe-switch device
+ */
+static struct idt_89hpesx_dev *idt_create_pdev(struct i2c_client *client)
+{
+ struct idt_89hpesx_dev *pdev;
+
+ /* Allocate memory for driver data */
+ pdev = devm_kmalloc(&client->dev, sizeof(struct idt_89hpesx_dev),
+ GFP_KERNEL);
+ if (pdev == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ /* Initialize basic fields of the data */
+ pdev->client = client;
+ i2c_set_clientdata(client, pdev);
+
+ /* Read firmware nodes information */
+ idt_get_fw_data(pdev);
+
+ /* Initialize basic CSR CMD field - use full DWORD-sized r/w ops */
+ pdev->inicsrcmd = CSR_DWE;
+ pdev->csr = CSR_DEF;
+
+ /* Enable Packet Error Checking if it's supported by adapter */
+ if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_PEC)) {
+ pdev->iniccode = CCODE_PEC;
+ client->flags |= I2C_CLIENT_PEC;
+ } else /* PEC is unsupported */ {
+ pdev->iniccode = 0;
+ }
+
+ return pdev;
+}
+
+/*
+ * idt_free_pdev() - free data structure of the driver
+ * @pdev: Pointer to the driver data
+ */
+static void idt_free_pdev(struct idt_89hpesx_dev *pdev)
+{
+ /* Clear driver data from device private field */
+ i2c_set_clientdata(pdev->client, NULL);
+}
+
+/*
+ * idt_set_smbus_ops() - set supported SMBus operations
+ * @pdev: Pointer to the driver data
+ * Return status of smbus check operations
+ */
+static int idt_set_smbus_ops(struct idt_89hpesx_dev *pdev)
+{
+ struct i2c_adapter *adapter = pdev->client->adapter;
+ struct device *dev = &pdev->client->dev;
+
+ /* Check i2c adapter read functionality */
+ if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
+ pdev->smb_read = idt_smb_read_block;
+ dev_dbg(dev, "SMBus block-read op chosen");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ pdev->smb_read = idt_smb_read_i2c_block;
+ dev_dbg(dev, "SMBus i2c-block-read op chosen");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_READ_WORD_DATA) &&
+ i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+ pdev->smb_read = idt_smb_read_word;
+ dev_warn(dev, "Use slow word/byte SMBus read ops");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+ pdev->smb_read = idt_smb_read_byte;
+ dev_warn(dev, "Use slow byte SMBus read op");
+ } else /* no supported smbus read operations */ {
+ dev_err(dev, "No supported SMBus read op");
+ return -EPFNOSUPPORT;
+ }
+
+ /* Check i2c adapter write functionality */
+ if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)) {
+ pdev->smb_write = idt_smb_write_block;
+ dev_dbg(dev, "SMBus block-write op chosen");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) {
+ pdev->smb_write = idt_smb_write_i2c_block;
+ dev_dbg(dev, "SMBus i2c-block-write op chosen");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_WRITE_WORD_DATA) &&
+ i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+ pdev->smb_write = idt_smb_write_word;
+ dev_warn(dev, "Use slow word/byte SMBus write op");
+ } else if (i2c_check_functionality(adapter,
+ I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+ pdev->smb_write = idt_smb_write_byte;
+ dev_warn(dev, "Use slow byte SMBus write op");
+ } else /* no supported smbus write operations */ {
+ dev_err(dev, "No supported SMBus write op");
+ return -EPFNOSUPPORT;
+ }
+
+ /* Initialize IDT SMBus slave interface mutex */
+ mutex_init(&pdev->smb_mtx);
+
+ return 0;
+}
+
+/*
+ * idt_check_dev() - check whether it's really IDT 89HPESx device
+ * @pdev: Pointer to the driver data
+ * Return status of i2c adapter check operation
+ */
+static int idt_check_dev(struct idt_89hpesx_dev *pdev)
+{
+ struct device *dev = &pdev->client->dev;
+ u32 viddid;
+ int ret;
+
+ /* Read VID and DID directly from IDT memory space */
+ ret = idt_csr_read(pdev, IDT_VIDDID_CSR, &viddid);
+ if (ret != 0) {
+ dev_err(dev, "Failed to read VID/DID");
+ return ret;
+ }
+
+ /* Check whether it's IDT device */
+ if ((viddid & IDT_VID_MASK) != PCI_VENDOR_ID_IDT) {
+ dev_err(dev, "Got unsupported VID/DID: 0x%08x", viddid);
+ return -ENODEV;
+ }
+
+ dev_info(dev, "Found IDT 89HPES device VID:0x%04x, DID:0x%04x",
+ (viddid & IDT_VID_MASK), (viddid >> 16));
+
+ return 0;
+}
+
+/*
+ * idt_create_sysfs_files() - create sysfs attribute files
+ * @pdev: Pointer to the driver data
+ * Return status of operation
+ */
+static int idt_create_sysfs_files(struct idt_89hpesx_dev *pdev)
+{
+ struct device *dev = &pdev->client->dev;
+ int ret;
+
+ /* Don't do anything if EEPROM isn't accessible */
+ if (pdev->eesize == 0) {
+ dev_dbg(dev, "Skip creating sysfs-files");
+ return 0;
+ }
+
+ /* Allocate memory for attribute file */
+ pdev->ee_file = devm_kmalloc(dev, sizeof(*pdev->ee_file), GFP_KERNEL);
+ if (!pdev->ee_file)
+ return -ENOMEM;
+
+ /* Copy the declared EEPROM attr structure to change some of fields */
+ memcpy(pdev->ee_file, &bin_attr_eeprom, sizeof(*pdev->ee_file));
+
+ /* In case of read-only EEPROM get rid of write ability */
+ if (pdev->eero) {
+ pdev->ee_file->attr.mode &= ~0200;
+ pdev->ee_file->write = NULL;
+ }
+ /* Create EEPROM sysfs file */
+ pdev->ee_file->size = pdev->eesize;
+ ret = sysfs_create_bin_file(&dev->kobj, pdev->ee_file);
+ if (ret != 0) {
+ dev_err(dev, "Failed to create EEPROM sysfs-node");
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * idt_remove_sysfs_files() - remove sysfs attribute files
+ * @pdev: Pointer to the driver data
+ */
+static void idt_remove_sysfs_files(struct idt_89hpesx_dev *pdev)
+{
+ struct device *dev = &pdev->client->dev;
+
+ /* Don't do anything if EEPROM wasn't accessible */
+ if (pdev->eesize == 0)
+ return;
+
+ /* Remove EEPROM sysfs file */
+ sysfs_remove_bin_file(&dev->kobj, pdev->ee_file);
+}
+
+/*
+ * idt_create_dbgfs_files() - create debugfs files
+ * @pdev: Pointer to the driver data
+ */
+#define CSRNAME_LEN ((size_t)32)
+static void idt_create_dbgfs_files(struct idt_89hpesx_dev *pdev)
+{
+ struct i2c_client *cli = pdev->client;
+ char fname[CSRNAME_LEN];
+
+ /* Create Debugfs directory for CSR file */
+ snprintf(fname, CSRNAME_LEN, "%d-%04hx", cli->adapter->nr, cli->addr);
+ pdev->csr_dir = debugfs_create_dir(fname, csr_dbgdir);
+
+ /* Create Debugfs file for CSR read/write operations */
+ debugfs_create_file(cli->name, 0600, pdev->csr_dir, pdev,
+ &csr_dbgfs_ops);
+}
+
+/*
+ * idt_remove_dbgfs_files() - remove debugfs files
+ * @pdev: Pointer to the driver data
+ */
+static void idt_remove_dbgfs_files(struct idt_89hpesx_dev *pdev)
+{
+ /* Remove CSR directory and it sysfs-node */
+ debugfs_remove_recursive(pdev->csr_dir);
+}
+
+/*
+ * idt_probe() - IDT 89HPESx driver probe() callback method
+ */
+static int idt_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct idt_89hpesx_dev *pdev;
+ int ret;
+
+ /* Create driver data */
+ pdev = idt_create_pdev(client);
+ if (IS_ERR(pdev))
+ return PTR_ERR(pdev);
+
+ /* Set SMBus operations */
+ ret = idt_set_smbus_ops(pdev);
+ if (ret != 0)
+ goto err_free_pdev;
+
+ /* Check whether it is truly IDT 89HPESx device */
+ ret = idt_check_dev(pdev);
+ if (ret != 0)
+ goto err_free_pdev;
+
+ /* Create sysfs files */
+ ret = idt_create_sysfs_files(pdev);
+ if (ret != 0)
+ goto err_free_pdev;
+
+ /* Create debugfs files */
+ idt_create_dbgfs_files(pdev);
+
+ return 0;
+
+err_free_pdev:
+ idt_free_pdev(pdev);
+
+ return ret;
+}
+
+/*
+ * idt_remove() - IDT 89HPESx driver remove() callback method
+ */
+static void idt_remove(struct i2c_client *client)
+{
+ struct idt_89hpesx_dev *pdev = i2c_get_clientdata(client);
+
+ /* Remove debugfs files first */
+ idt_remove_dbgfs_files(pdev);
+
+ /* Remove sysfs files */
+ idt_remove_sysfs_files(pdev);
+
+ /* Discard driver data structure */
+ idt_free_pdev(pdev);
+}
+
+/*
+ * ee_ids - array of supported EEPROMs
+ */
+static const struct i2c_device_id ee_ids[] = {
+ { "24c32", 4096},
+ { "24c64", 8192},
+ { "24c128", 16384},
+ { "24c256", 32768},
+ { "24c512", 65536},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ee_ids);
+
+/*
+ * idt_ids - supported IDT 89HPESx devices
+ */
+static const struct i2c_device_id idt_ids[] = {
+ { "89hpes8nt2", 0 },
+ { "89hpes12nt3", 0 },
+
+ { "89hpes24nt6ag2", 0 },
+ { "89hpes32nt8ag2", 0 },
+ { "89hpes32nt8bg2", 0 },
+ { "89hpes12nt12g2", 0 },
+ { "89hpes16nt16g2", 0 },
+ { "89hpes24nt24g2", 0 },
+ { "89hpes32nt24ag2", 0 },
+ { "89hpes32nt24bg2", 0 },
+
+ { "89hpes12n3", 0 },
+ { "89hpes12n3a", 0 },
+ { "89hpes24n3", 0 },
+ { "89hpes24n3a", 0 },
+
+ { "89hpes32h8", 0 },
+ { "89hpes32h8g2", 0 },
+ { "89hpes48h12", 0 },
+ { "89hpes48h12g2", 0 },
+ { "89hpes48h12ag2", 0 },
+ { "89hpes16h16", 0 },
+ { "89hpes22h16", 0 },
+ { "89hpes22h16g2", 0 },
+ { "89hpes34h16", 0 },
+ { "89hpes34h16g2", 0 },
+ { "89hpes64h16", 0 },
+ { "89hpes64h16g2", 0 },
+ { "89hpes64h16ag2", 0 },
+
+ /* { "89hpes3t3", 0 }, // No SMBus-slave iface */
+ { "89hpes12t3g2", 0 },
+ { "89hpes24t3g2", 0 },
+ /* { "89hpes4t4", 0 }, // No SMBus-slave iface */
+ { "89hpes16t4", 0 },
+ { "89hpes4t4g2", 0 },
+ { "89hpes10t4g2", 0 },
+ { "89hpes16t4g2", 0 },
+ { "89hpes16t4ag2", 0 },
+ { "89hpes5t5", 0 },
+ { "89hpes6t5", 0 },
+ { "89hpes8t5", 0 },
+ { "89hpes8t5a", 0 },
+ { "89hpes24t6", 0 },
+ { "89hpes6t6g2", 0 },
+ { "89hpes24t6g2", 0 },
+ { "89hpes16t7", 0 },
+ { "89hpes32t8", 0 },
+ { "89hpes32t8g2", 0 },
+ { "89hpes48t12", 0 },
+ { "89hpes48t12g2", 0 },
+ { /* END OF LIST */ }
+};
+MODULE_DEVICE_TABLE(i2c, idt_ids);
+
+static const struct of_device_id idt_of_match[] = {
+ { .compatible = "idt,89hpes8nt2", },
+ { .compatible = "idt,89hpes12nt3", },
+
+ { .compatible = "idt,89hpes24nt6ag2", },
+ { .compatible = "idt,89hpes32nt8ag2", },
+ { .compatible = "idt,89hpes32nt8bg2", },
+ { .compatible = "idt,89hpes12nt12g2", },
+ { .compatible = "idt,89hpes16nt16g2", },
+ { .compatible = "idt,89hpes24nt24g2", },
+ { .compatible = "idt,89hpes32nt24ag2", },
+ { .compatible = "idt,89hpes32nt24bg2", },
+
+ { .compatible = "idt,89hpes12n3", },
+ { .compatible = "idt,89hpes12n3a", },
+ { .compatible = "idt,89hpes24n3", },
+ { .compatible = "idt,89hpes24n3a", },
+
+ { .compatible = "idt,89hpes32h8", },
+ { .compatible = "idt,89hpes32h8g2", },
+ { .compatible = "idt,89hpes48h12", },
+ { .compatible = "idt,89hpes48h12g2", },
+ { .compatible = "idt,89hpes48h12ag2", },
+ { .compatible = "idt,89hpes16h16", },
+ { .compatible = "idt,89hpes22h16", },
+ { .compatible = "idt,89hpes22h16g2", },
+ { .compatible = "idt,89hpes34h16", },
+ { .compatible = "idt,89hpes34h16g2", },
+ { .compatible = "idt,89hpes64h16", },
+ { .compatible = "idt,89hpes64h16g2", },
+ { .compatible = "idt,89hpes64h16ag2", },
+
+ { .compatible = "idt,89hpes12t3g2", },
+ { .compatible = "idt,89hpes24t3g2", },
+
+ { .compatible = "idt,89hpes16t4", },
+ { .compatible = "idt,89hpes4t4g2", },
+ { .compatible = "idt,89hpes10t4g2", },
+ { .compatible = "idt,89hpes16t4g2", },
+ { .compatible = "idt,89hpes16t4ag2", },
+ { .compatible = "idt,89hpes5t5", },
+ { .compatible = "idt,89hpes6t5", },
+ { .compatible = "idt,89hpes8t5", },
+ { .compatible = "idt,89hpes8t5a", },
+ { .compatible = "idt,89hpes24t6", },
+ { .compatible = "idt,89hpes6t6g2", },
+ { .compatible = "idt,89hpes24t6g2", },
+ { .compatible = "idt,89hpes16t7", },
+ { .compatible = "idt,89hpes32t8", },
+ { .compatible = "idt,89hpes32t8g2", },
+ { .compatible = "idt,89hpes48t12", },
+ { .compatible = "idt,89hpes48t12g2", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, idt_of_match);
+
+/*
+ * idt_driver - IDT 89HPESx driver structure
+ */
+static struct i2c_driver idt_driver = {
+ .driver = {
+ .name = IDT_NAME,
+ .of_match_table = idt_of_match,
+ },
+ .probe = idt_probe,
+ .remove = idt_remove,
+ .id_table = idt_ids,
+};
+
+/*
+ * idt_init() - IDT 89HPESx driver init() callback method
+ */
+static int __init idt_init(void)
+{
+ int ret;
+
+ /* Create Debugfs directory first */
+ if (debugfs_initialized())
+ csr_dbgdir = debugfs_create_dir("idt_csr", NULL);
+
+ /* Add new i2c-device driver */
+ ret = i2c_add_driver(&idt_driver);
+ if (ret) {
+ debugfs_remove_recursive(csr_dbgdir);
+ return ret;
+ }
+
+ return 0;
+}
+module_init(idt_init);
+
+/*
+ * idt_exit() - IDT 89HPESx driver exit() callback method
+ */
+static void __exit idt_exit(void)
+{
+ /* Discard debugfs directory and all files if any */
+ debugfs_remove_recursive(csr_dbgdir);
+
+ /* Unregister i2c-device driver */
+ i2c_del_driver(&idt_driver);
+}
+module_exit(idt_exit);
diff --git a/drivers/misc/eeprom/max6875.c b/drivers/misc/eeprom/max6875.c
new file mode 100644
index 000000000..6bd4f4339
--- /dev/null
+++ b/drivers/misc/eeprom/max6875.c
@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * max6875.c - driver for MAX6874/MAX6875
+ *
+ * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
+ *
+ * Based on eeprom.c
+ *
+ * The MAX6875 has a bank of registers and two banks of EEPROM.
+ * Address ranges are defined as follows:
+ * * 0x0000 - 0x0046 = configuration registers
+ * * 0x8000 - 0x8046 = configuration EEPROM
+ * * 0x8100 - 0x82FF = user EEPROM
+ *
+ * This driver makes the user EEPROM available for read.
+ *
+ * The registers & config EEPROM should be accessed via i2c-dev.
+ *
+ * The MAX6875 ignores the lowest address bit, so each chip responds to
+ * two addresses - 0x50/0x51 and 0x52/0x53.
+ *
+ * Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
+ * address, so this driver is destructive if loaded for the wrong EEPROM chip.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/mutex.h>
+
+/* The MAX6875 can only read/write 16 bytes at a time */
+#define SLICE_SIZE 16
+#define SLICE_BITS 4
+
+/* USER EEPROM is at addresses 0x8100 - 0x82FF */
+#define USER_EEPROM_BASE 0x8100
+#define USER_EEPROM_SIZE 0x0200
+#define USER_EEPROM_SLICES 32
+
+/* MAX6875 commands */
+#define MAX6875_CMD_BLK_READ 0x84
+
+/* Each client has this additional data */
+struct max6875_data {
+ struct i2c_client *fake_client;
+ struct mutex update_lock;
+
+ u32 valid;
+ u8 data[USER_EEPROM_SIZE];
+ unsigned long last_updated[USER_EEPROM_SLICES];
+};
+
+static void max6875_update_slice(struct i2c_client *client, int slice)
+{
+ struct max6875_data *data = i2c_get_clientdata(client);
+ int i, j, addr;
+ u8 *buf;
+
+ if (slice >= USER_EEPROM_SLICES)
+ return;
+
+ mutex_lock(&data->update_lock);
+
+ buf = &data->data[slice << SLICE_BITS];
+
+ if (!(data->valid & (1 << slice)) ||
+ time_after(jiffies, data->last_updated[slice])) {
+
+ dev_dbg(&client->dev, "Starting update of slice %u\n", slice);
+
+ data->valid &= ~(1 << slice);
+
+ addr = USER_EEPROM_BASE + (slice << SLICE_BITS);
+
+ /* select the eeprom address */
+ if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
+ dev_err(&client->dev, "address set failed\n");
+ goto exit_up;
+ }
+
+ if (i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+ if (i2c_smbus_read_i2c_block_data(client,
+ MAX6875_CMD_BLK_READ,
+ SLICE_SIZE,
+ buf) != SLICE_SIZE) {
+ goto exit_up;
+ }
+ } else {
+ for (i = 0; i < SLICE_SIZE; i++) {
+ j = i2c_smbus_read_byte(client);
+ if (j < 0) {
+ goto exit_up;
+ }
+ buf[i] = j;
+ }
+ }
+ data->last_updated[slice] = jiffies;
+ data->valid |= (1 << slice);
+ }
+exit_up:
+ mutex_unlock(&data->update_lock);
+}
+
+static ssize_t max6875_read(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct i2c_client *client = kobj_to_i2c_client(kobj);
+ struct max6875_data *data = i2c_get_clientdata(client);
+ int slice, max_slice;
+
+ /* refresh slices which contain requested bytes */
+ max_slice = (off + count - 1) >> SLICE_BITS;
+ for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++)
+ max6875_update_slice(client, slice);
+
+ memcpy(buf, &data->data[off], count);
+
+ return count;
+}
+
+static const struct bin_attribute user_eeprom_attr = {
+ .attr = {
+ .name = "eeprom",
+ .mode = S_IRUGO,
+ },
+ .size = USER_EEPROM_SIZE,
+ .read = max6875_read,
+};
+
+static int max6875_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ struct max6875_data *data;
+ int err;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
+ | I2C_FUNC_SMBUS_READ_BYTE))
+ return -ENODEV;
+
+ /* Only bind to even addresses */
+ if (client->addr & 1)
+ return -ENODEV;
+
+ data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* A fake client is created on the odd address */
+ data->fake_client = i2c_new_dummy_device(client->adapter, client->addr + 1);
+ if (IS_ERR(data->fake_client)) {
+ err = PTR_ERR(data->fake_client);
+ goto exit_kfree;
+ }
+
+ /* Init real i2c_client */
+ i2c_set_clientdata(client, data);
+ mutex_init(&data->update_lock);
+
+ err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr);
+ if (err)
+ goto exit_remove_fake;
+
+ return 0;
+
+exit_remove_fake:
+ i2c_unregister_device(data->fake_client);
+exit_kfree:
+ kfree(data);
+ return err;
+}
+
+static void max6875_remove(struct i2c_client *client)
+{
+ struct max6875_data *data = i2c_get_clientdata(client);
+
+ i2c_unregister_device(data->fake_client);
+
+ sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
+ kfree(data);
+}
+
+static const struct i2c_device_id max6875_id[] = {
+ { "max6875", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max6875_id);
+
+static struct i2c_driver max6875_driver = {
+ .driver = {
+ .name = "max6875",
+ },
+ .probe = max6875_probe,
+ .remove = max6875_remove,
+ .id_table = max6875_id,
+};
+
+module_i2c_driver(max6875_driver);
+
+MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
+MODULE_DESCRIPTION("MAX6875 driver");
+MODULE_LICENSE("GPL");