diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/mfd/rsmu_spi.c | 271 |
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"); |