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-rw-r--r--drivers/mfd/rsmu_spi.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/mfd/rsmu_spi.c b/drivers/mfd/rsmu_spi.c
new file mode 100644
index 000000000..d2f3d8f1e
--- /dev/null
+++ b/drivers/mfd/rsmu_spi.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * SPI driver for Renesas Synchronization Management Unit (SMU) devices.
+ *
+ * Copyright (C) 2021 Integrated Device Technology, Inc., a Renesas Company.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/rsmu.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "rsmu.h"
+
+#define RSMU_CM_PAGE_ADDR 0x7C
+#define RSMU_SABRE_PAGE_ADDR 0x7F
+#define RSMU_HIGHER_ADDR_MASK 0xFF80
+#define RSMU_HIGHER_ADDR_SHIFT 7
+#define RSMU_LOWER_ADDR_MASK 0x7F
+
+static int rsmu_read_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
+{
+ struct spi_device *client = to_spi_device(rsmu->dev);
+ struct spi_transfer xfer = {0};
+ struct spi_message msg;
+ u8 cmd[256] = {0};
+ u8 rsp[256] = {0};
+ int ret;
+
+ cmd[0] = reg | 0x80;
+ xfer.rx_buf = rsp;
+ xfer.len = bytes + 1;
+ xfer.tx_buf = cmd;
+ xfer.bits_per_word = client->bits_per_word;
+ xfer.speed_hz = client->max_speed_hz;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ /*
+ * 4-wire SPI is a shift register, so for every byte you send,
+ * you get one back at the same time. Example read from 0xC024,
+ * which has value of 0x2D
+ *
+ * MOSI:
+ * 7C 00 C0 #Set page register
+ * A4 00 #MSB is set, so this is read command
+ * MISO:
+ * XX 2D #XX is a dummy byte from sending A4 and we
+ * need to throw it away
+ */
+ ret = spi_sync(client, &msg);
+ if (ret >= 0)
+ memcpy(buf, &rsp[1], xfer.len-1);
+
+ return ret;
+}
+
+static int rsmu_write_device(struct rsmu_ddata *rsmu, u8 reg, u8 *buf, u16 bytes)
+{
+ struct spi_device *client = to_spi_device(rsmu->dev);
+ struct spi_transfer xfer = {0};
+ struct spi_message msg;
+ u8 cmd[256] = {0};
+
+ cmd[0] = reg;
+ memcpy(&cmd[1], buf, bytes);
+
+ xfer.len = bytes + 1;
+ xfer.tx_buf = cmd;
+ xfer.bits_per_word = client->bits_per_word;
+ xfer.speed_hz = client->max_speed_hz;
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ return spi_sync(client, &msg);
+}
+
+/*
+ * 1-byte (1B) offset addressing:
+ * 16-bit register address: the lower 7 bits of the register address come
+ * from the offset addr byte and the upper 9 bits come from the page register.
+ */
+static int rsmu_write_page_register(struct rsmu_ddata *rsmu, u16 reg)
+{
+ u8 page_reg;
+ u8 buf[2];
+ u16 bytes;
+ u16 page;
+ int err;
+
+ switch (rsmu->type) {
+ case RSMU_CM:
+ page_reg = RSMU_CM_PAGE_ADDR;
+ page = reg & RSMU_HIGHER_ADDR_MASK;
+ buf[0] = (u8)(page & 0xff);
+ buf[1] = (u8)((page >> 8) & 0xff);
+ bytes = 2;
+ break;
+ case RSMU_SABRE:
+ page_reg = RSMU_SABRE_PAGE_ADDR;
+ page = reg >> RSMU_HIGHER_ADDR_SHIFT;
+ buf[0] = (u8)(page & 0xff);
+ bytes = 1;
+ break;
+ default:
+ dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
+ return -ENODEV;
+ }
+
+ /* Simply return if we are on the same page */
+ if (rsmu->page == page)
+ return 0;
+
+ err = rsmu_write_device(rsmu, page_reg, buf, bytes);
+ if (err)
+ dev_err(rsmu->dev, "Failed to set page offset 0x%x\n", page);
+ else
+ /* Remember the last page */
+ rsmu->page = page;
+
+ return err;
+}
+
+static int rsmu_reg_read(void *context, unsigned int reg, unsigned int *val)
+{
+ struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
+ u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
+ int err;
+
+ err = rsmu_write_page_register(rsmu, reg);
+ if (err)
+ return err;
+
+ err = rsmu_read_device(rsmu, addr, (u8 *)val, 1);
+ if (err)
+ dev_err(rsmu->dev, "Failed to read offset address 0x%x\n", addr);
+
+ return err;
+}
+
+static int rsmu_reg_write(void *context, unsigned int reg, unsigned int val)
+{
+ struct rsmu_ddata *rsmu = spi_get_drvdata((struct spi_device *)context);
+ u8 addr = (u8)(reg & RSMU_LOWER_ADDR_MASK);
+ u8 data = (u8)val;
+ int err;
+
+ err = rsmu_write_page_register(rsmu, reg);
+ if (err)
+ return err;
+
+ err = rsmu_write_device(rsmu, addr, &data, 1);
+ if (err)
+ dev_err(rsmu->dev,
+ "Failed to write offset address 0x%x\n", addr);
+
+ return err;
+}
+
+static const struct regmap_config rsmu_cm_regmap_config = {
+ .reg_bits = 16,
+ .val_bits = 8,
+ .max_register = 0xD000,
+ .reg_read = rsmu_reg_read,
+ .reg_write = rsmu_reg_write,
+ .cache_type = REGCACHE_NONE,
+};
+
+static const struct regmap_config rsmu_sabre_regmap_config = {
+ .reg_bits = 16,
+ .val_bits = 8,
+ .max_register = 0x400,
+ .reg_read = rsmu_reg_read,
+ .reg_write = rsmu_reg_write,
+ .cache_type = REGCACHE_NONE,
+};
+
+static int rsmu_spi_probe(struct spi_device *client)
+{
+ const struct spi_device_id *id = spi_get_device_id(client);
+ const struct regmap_config *cfg;
+ struct rsmu_ddata *rsmu;
+ int ret;
+
+ rsmu = devm_kzalloc(&client->dev, sizeof(*rsmu), GFP_KERNEL);
+ if (!rsmu)
+ return -ENOMEM;
+
+ spi_set_drvdata(client, rsmu);
+
+ rsmu->dev = &client->dev;
+ rsmu->type = (enum rsmu_type)id->driver_data;
+
+ /* Initialize regmap */
+ switch (rsmu->type) {
+ case RSMU_CM:
+ cfg = &rsmu_cm_regmap_config;
+ break;
+ case RSMU_SABRE:
+ cfg = &rsmu_sabre_regmap_config;
+ break;
+ default:
+ dev_err(rsmu->dev, "Unsupported RSMU device type: %d\n", rsmu->type);
+ return -ENODEV;
+ }
+
+ rsmu->regmap = devm_regmap_init(&client->dev, NULL, client, cfg);
+ if (IS_ERR(rsmu->regmap)) {
+ ret = PTR_ERR(rsmu->regmap);
+ dev_err(rsmu->dev, "Failed to allocate register map: %d\n", ret);
+ return ret;
+ }
+
+ return rsmu_core_init(rsmu);
+}
+
+static void rsmu_spi_remove(struct spi_device *client)
+{
+ struct rsmu_ddata *rsmu = spi_get_drvdata(client);
+
+ rsmu_core_exit(rsmu);
+}
+
+static const struct spi_device_id rsmu_spi_id[] = {
+ { "8a34000", RSMU_CM },
+ { "8a34001", RSMU_CM },
+ { "82p33810", RSMU_SABRE },
+ { "82p33811", RSMU_SABRE },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, rsmu_spi_id);
+
+static const struct of_device_id rsmu_spi_of_match[] = {
+ { .compatible = "idt,8a34000", .data = (void *)RSMU_CM },
+ { .compatible = "idt,8a34001", .data = (void *)RSMU_CM },
+ { .compatible = "idt,82p33810", .data = (void *)RSMU_SABRE },
+ { .compatible = "idt,82p33811", .data = (void *)RSMU_SABRE },
+ {}
+};
+MODULE_DEVICE_TABLE(of, rsmu_spi_of_match);
+
+static struct spi_driver rsmu_spi_driver = {
+ .driver = {
+ .name = "rsmu-spi",
+ .of_match_table = of_match_ptr(rsmu_spi_of_match),
+ },
+ .probe = rsmu_spi_probe,
+ .remove = rsmu_spi_remove,
+ .id_table = rsmu_spi_id,
+};
+
+static int __init rsmu_spi_init(void)
+{
+ return spi_register_driver(&rsmu_spi_driver);
+}
+subsys_initcall(rsmu_spi_init);
+
+static void __exit rsmu_spi_exit(void)
+{
+ spi_unregister_driver(&rsmu_spi_driver);
+}
+module_exit(rsmu_spi_exit);
+
+MODULE_DESCRIPTION("Renesas SMU SPI driver");
+MODULE_LICENSE("GPL");