diff options
Diffstat (limited to 'drivers/misc/eeprom/at24.c')
| -rw-r--r-- | drivers/misc/eeprom/at24.c | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c new file mode 100644 index 000000000..dc3537651 --- /dev/null +++ b/drivers/misc/eeprom/at24.c @@ -0,0 +1,805 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * at24.c - handle most I2C EEPROMs + * + * Copyright (C) 2005-2007 David Brownell + * Copyright (C) 2008 Wolfram Sang, Pengutronix + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/slab.h> +#include <linux/delay.h> +#include <linux/mutex.h> +#include <linux/mod_devicetable.h> +#include <linux/log2.h> +#include <linux/bitops.h> +#include <linux/jiffies.h> +#include <linux/property.h> +#include <linux/acpi.h> +#include <linux/i2c.h> +#include <linux/nvmem-provider.h> +#include <linux/regmap.h> +#include <linux/platform_data/at24.h> +#include <linux/pm_runtime.h> +#include <linux/gpio/consumer.h> + +/* + * 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_client { + struct i2c_client *client; + struct regmap *regmap; +}; + +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 gpio_desc *wp_gpio; + + /* + * Some chips tie up multiple I2C addresses; dummy devices reserve + * them for us, and we'll use them with SMBus calls. + */ + struct at24_client client[]; +}; + +/* + * 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 { + /* + * these fields mirror their equivalents in + * struct at24_platform_data + */ + u32 byte_len; + u8 flags; +}; + +#define AT24_CHIP_DATA(_name, _len, _flags) \ + static const struct at24_chip_data _name = { \ + .byte_len = _len, .flags = _flags, \ + } + +/* 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); +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(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 }, + { "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 }, + { "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,24c2048", .data = &at24_data_24c2048 }, + { /* END OF LIST */ }, +}; +MODULE_DEVICE_TABLE(of, at24_of_match); + +static const struct acpi_device_id at24_acpi_ids[] = { + { "INT3499", (kernel_ulong_t)&at24_data_INT3499 }, + { /* 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 at24_client *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[i]; +} + +static struct device *at24_base_client_dev(struct at24_data *at24) +{ + return &at24->client[0].client->dev; +} + +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 at24_client *at24_client; + struct i2c_client *client; + struct regmap *regmap; + int ret; + + at24_client = at24_translate_offset(at24, &offset); + regmap = at24_client->regmap; + client = at24_client->client; + 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(&client->dev, "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 at24_client *at24_client; + struct i2c_client *client; + struct regmap *regmap; + int ret; + + at24_client = at24_translate_offset(at24, &offset); + regmap = at24_client->regmap; + client = at24_client->client; + 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(&client->dev, "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 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); + + while (count) { + ret = at24_regmap_read(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 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); + gpiod_set_value_cansleep(at24->wp_gpio, 0); + + while (count) { + ret = at24_regmap_write(at24, buf, off, count); + if (ret < 0) { + gpiod_set_value_cansleep(at24->wp_gpio, 1); + mutex_unlock(&at24->lock); + pm_runtime_put(dev); + return ret; + } + buf += ret; + off += ret; + count -= ret; + } + + gpiod_set_value_cansleep(at24->wp_gpio, 1); + mutex_unlock(&at24->lock); + + pm_runtime_put(dev); + + return 0; +} + +static void at24_properties_to_pdata(struct device *dev, + struct at24_platform_data *chip) +{ + int err; + u32 val; + + if (device_property_present(dev, "read-only")) + chip->flags |= AT24_FLAG_READONLY; + if (device_property_present(dev, "no-read-rollover")) + chip->flags |= AT24_FLAG_NO_RDROL; + + err = device_property_read_u32(dev, "address-width", &val); + if (!err) { + switch (val) { + case 8: + if (chip->flags & AT24_FLAG_ADDR16) + dev_warn(dev, "Override address width to be 8, while default is 16\n"); + chip->flags &= ~AT24_FLAG_ADDR16; + break; + case 16: + chip->flags |= AT24_FLAG_ADDR16; + break; + default: + dev_warn(dev, "Bad \"address-width\" property: %u\n", + val); + } + } + + err = device_property_read_u32(dev, "size", &val); + if (!err) + chip->byte_len = val; + + err = device_property_read_u32(dev, "pagesize", &val); + if (!err) { + chip->page_size = val; + } else { + /* + * This is slow, but we can't know all eeproms, so we better + * play safe. Specifying custom eeprom-types via platform_data + * is recommended anyhow. + */ + chip->page_size = 1; + } +} + +static int at24_get_pdata(struct device *dev, struct at24_platform_data *pdata) +{ + struct device_node *of_node = dev->of_node; + const struct at24_chip_data *cdata; + const struct i2c_device_id *id; + struct at24_platform_data *pd; + + pd = dev_get_platdata(dev); + if (pd) { + memcpy(pdata, pd, sizeof(*pdata)); + return 0; + } + + 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 -ENODEV; + + pdata->byte_len = cdata->byte_len; + pdata->flags = cdata->flags; + at24_properties_to_pdata(dev, pdata); + + return 0; +} + +static void at24_remove_dummy_clients(struct at24_data *at24) +{ + int i; + + for (i = 1; i < at24->num_addresses; i++) + i2c_unregister_device(at24->client[i].client); +} + +static int at24_make_dummy_client(struct at24_data *at24, unsigned int index, + struct regmap_config *regmap_config) +{ + struct i2c_client *base_client, *dummy_client; + unsigned short int addr; + struct regmap *regmap; + struct device *dev; + + base_client = at24->client[0].client; + dev = &base_client->dev; + addr = base_client->addr + index; + + dummy_client = i2c_new_dummy(base_client->adapter, + base_client->addr + index); + if (!dummy_client) { + dev_err(dev, "address 0x%02x unavailable\n", addr); + return -EADDRINUSE; + } + + regmap = devm_regmap_init_i2c(dummy_client, regmap_config); + if (IS_ERR(regmap)) { + i2c_unregister_device(dummy_client); + return PTR_ERR(regmap); + } + + at24->client[index].client = dummy_client; + at24->client[index].regmap = 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 = { }; + struct at24_platform_data pdata = { }; + struct device *dev = &client->dev; + bool i2c_fn_i2c, i2c_fn_block; + unsigned int i, num_addresses; + struct at24_data *at24; + struct regmap *regmap; + size_t at24_size; + 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); + + err = at24_get_pdata(dev, &pdata); + if (err) + return err; + + if (!i2c_fn_i2c && !i2c_fn_block) + pdata.page_size = 1; + + if (!pdata.page_size) { + dev_err(dev, "page_size must not be 0!\n"); + return -EINVAL; + } + + if (!is_power_of_2(pdata.page_size)) + dev_warn(dev, "page_size looks suspicious (no power of 2)!\n"); + + if (pdata.flags & AT24_FLAG_TAKE8ADDR) + num_addresses = 8; + else + num_addresses = DIV_ROUND_UP(pdata.byte_len, + (pdata.flags & AT24_FLAG_ADDR16) ? 65536 : 256); + + if ((pdata.flags & AT24_FLAG_SERIAL) && (pdata.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 = (pdata.flags & AT24_FLAG_ADDR16) ? 16 : 8; + regmap_config.disable_locking = true; + + regmap = devm_regmap_init_i2c(client, ®map_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + at24_size = sizeof(*at24) + num_addresses * sizeof(struct at24_client); + at24 = devm_kzalloc(dev, at24_size, GFP_KERNEL); + if (!at24) + return -ENOMEM; + + mutex_init(&at24->lock); + at24->byte_len = pdata.byte_len; + at24->page_size = pdata.page_size; + at24->flags = pdata.flags; + at24->num_addresses = num_addresses; + at24->offset_adj = at24_get_offset_adj(pdata.flags, pdata.byte_len); + at24->client[0].client = client; + at24->client[0].regmap = regmap; + + at24->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_HIGH); + if (IS_ERR(at24->wp_gpio)) + return PTR_ERR(at24->wp_gpio); + + writable = !(pdata.flags & AT24_FLAG_READONLY); + if (writable) { + at24->write_max = min_t(unsigned int, + pdata.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, ®map_config); + if (err) { + at24_remove_dummy_clients(at24); + return err; + } + } + + i2c_set_clientdata(client, at24); + + /* enable runtime pm */ + pm_runtime_set_active(dev); + pm_runtime_enable(dev); + + /* + * Perform a one-byte test read to verify that the + * chip is functional. + */ + err = at24_read(at24, 0, &test_byte, 1); + pm_runtime_idle(dev); + if (err) { + err = -ENODEV; + goto err_clients; + } + + nvmem_config.name = dev_name(dev); + nvmem_config.dev = dev; + nvmem_config.read_only = !writable; + nvmem_config.root_only = !(pdata.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 = pdata.byte_len; + + at24->nvmem = devm_nvmem_register(dev, &nvmem_config); + if (IS_ERR(at24->nvmem)) { + err = PTR_ERR(at24->nvmem); + goto err_clients; + } + + dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n", + pdata.byte_len, client->name, + writable ? "writable" : "read-only", at24->write_max); + + /* export data to kernel code */ + if (pdata.setup) + pdata.setup(at24->nvmem, pdata.context); + + return 0; + +err_clients: + at24_remove_dummy_clients(at24); + pm_runtime_disable(dev); + + return err; +} + +static int at24_remove(struct i2c_client *client) +{ + struct at24_data *at24; + + at24 = i2c_get_clientdata(client); + + at24_remove_dummy_clients(at24); + pm_runtime_disable(&client->dev); + pm_runtime_set_suspended(&client->dev); + + return 0; +} + +static struct i2c_driver at24_driver = { + .driver = { + .name = "at24", + .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, +}; + +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"); |