diff options
Diffstat (limited to 'drivers/mfd/tps6594-i2c.c')
| -rw-r--r-- | drivers/mfd/tps6594-i2c.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/mfd/tps6594-i2c.c b/drivers/mfd/tps6594-i2c.c new file mode 100644 index 0000000000..899c88c0fe --- /dev/null +++ b/drivers/mfd/tps6594-i2c.c @@ -0,0 +1,244 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * I2C access driver for TI TPS6594/TPS6593/LP8764 PMICs + * + * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/ + */ + +#include <linux/crc8.h> +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/of_device.h> +#include <linux/regmap.h> + +#include <linux/mfd/tps6594.h> + +static bool enable_crc; +module_param(enable_crc, bool, 0444); +MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface"); + +DECLARE_CRC8_TABLE(tps6594_i2c_crc_table); + +static int tps6594_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + int ret = i2c_transfer(adap, msgs, num); + + if (ret == num) + return 0; + else if (ret < 0) + return ret; + else + return -EIO; +} + +static int tps6594_i2c_reg_read_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 *val) +{ + struct i2c_msg msgs[2]; + u8 buf_rx[] = { 0, 0 }; + /* I2C address = I2C base address + Page index */ + const u8 addr = client->addr + page; + /* + * CRC is calculated from every bit included in the protocol + * except the ACK bits from the target. Byte stream is: + * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0 + * - B1: reg + * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 1 + * - B3: val + * - B4: CRC from B0-B1-B2-B3 + */ + u8 crc_data[] = { addr << 1, reg, addr << 1 | 1, 0 }; + int ret; + + /* Write register */ + msgs[0].addr = addr; + msgs[0].flags = 0; + msgs[0].len = 1; + msgs[0].buf = ® + + /* Read data and CRC */ + msgs[1].addr = msgs[0].addr; + msgs[1].flags = I2C_M_RD; + msgs[1].len = 2; + msgs[1].buf = buf_rx; + + ret = tps6594_i2c_transfer(client->adapter, msgs, 2); + if (ret < 0) + return ret; + + crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0]; + if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE)) + return -EIO; + + return ret; +} + +static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val) +{ + struct i2c_msg msg; + u8 buf[] = { reg, val, 0 }; + /* I2C address = I2C base address + Page index */ + const u8 addr = client->addr + page; + /* + * CRC is calculated from every bit included in the protocol + * except the ACK bits from the target. Byte stream is: + * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0 + * - B1: reg + * - B2: val + * - B3: CRC from B0-B1-B2 + */ + const u8 crc_data[] = { addr << 1, reg, val }; + + /* Write register, data and CRC */ + msg.addr = addr; + msg.flags = client->flags & I2C_M_TEN; + msg.len = sizeof(buf); + msg.buf = buf; + + buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE); + + return tps6594_i2c_transfer(client->adapter, &msg, 1); +} + +static int tps6594_i2c_read(void *context, const void *reg_buf, size_t reg_size, + void *val_buf, size_t val_size) +{ + struct i2c_client *client = context; + struct tps6594 *tps = i2c_get_clientdata(client); + struct i2c_msg msgs[2]; + const u8 *reg_bytes = reg_buf; + u8 *val_bytes = val_buf; + const u8 page = reg_bytes[1]; + u8 reg = reg_bytes[0]; + int ret = 0; + int i; + + if (tps->use_crc) { + /* + * Auto-increment feature does not support CRC protocol. + * Converts the bulk read operation into a series of single read operations. + */ + for (i = 0 ; ret == 0 && i < val_size ; i++) + ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i); + + return ret; + } + + /* Write register: I2C address = I2C base address + Page index */ + msgs[0].addr = client->addr + page; + msgs[0].flags = 0; + msgs[0].len = 1; + msgs[0].buf = ® + + /* Read data */ + msgs[1].addr = msgs[0].addr; + msgs[1].flags = I2C_M_RD; + msgs[1].len = val_size; + msgs[1].buf = val_bytes; + + return tps6594_i2c_transfer(client->adapter, msgs, 2); +} + +static int tps6594_i2c_write(void *context, const void *data, size_t count) +{ + struct i2c_client *client = context; + struct tps6594 *tps = i2c_get_clientdata(client); + struct i2c_msg msg; + const u8 *bytes = data; + u8 *buf; + const u8 page = bytes[1]; + const u8 reg = bytes[0]; + int ret = 0; + int i; + + if (tps->use_crc) { + /* + * Auto-increment feature does not support CRC protocol. + * Converts the bulk write operation into a series of single write operations. + */ + for (i = 0 ; ret == 0 && i < count - 2 ; i++) + ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]); + + return ret; + } + + /* Setup buffer: page byte is not sent */ + buf = kzalloc(--count, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + buf[0] = reg; + for (i = 0 ; i < count - 1 ; i++) + buf[i + 1] = bytes[i + 2]; + + /* Write register and data: I2C address = I2C base address + Page index */ + msg.addr = client->addr + page; + msg.flags = client->flags & I2C_M_TEN; + msg.len = count; + msg.buf = buf; + + ret = tps6594_i2c_transfer(client->adapter, &msg, 1); + + kfree(buf); + return ret; +} + +static const struct regmap_config tps6594_i2c_regmap_config = { + .reg_bits = 16, + .val_bits = 8, + .max_register = TPS6594_REG_DWD_FAIL_CNT_REG, + .volatile_reg = tps6594_is_volatile_reg, + .read = tps6594_i2c_read, + .write = tps6594_i2c_write, +}; + +static const struct of_device_id tps6594_i2c_of_match_table[] = { + { .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, }, + { .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, }, + { .compatible = "ti,lp8764-q1", .data = (void *)LP8764, }, + {} +}; +MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table); + +static int tps6594_i2c_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct tps6594 *tps; + const struct of_device_id *match; + + tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL); + if (!tps) + return -ENOMEM; + + i2c_set_clientdata(client, tps); + + tps->dev = dev; + tps->reg = client->addr; + tps->irq = client->irq; + + tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config); + if (IS_ERR(tps->regmap)) + return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n"); + + match = of_match_device(tps6594_i2c_of_match_table, dev); + if (!match) + return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n"); + tps->chip_id = (unsigned long)match->data; + + crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL); + + return tps6594_device_init(tps, enable_crc); +} + +static struct i2c_driver tps6594_i2c_driver = { + .driver = { + .name = "tps6594", + .of_match_table = tps6594_i2c_of_match_table, + }, + .probe = tps6594_i2c_probe, +}; +module_i2c_driver(tps6594_i2c_driver); + +MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>"); +MODULE_DESCRIPTION("TPS6594 I2C Interface Driver"); +MODULE_LICENSE("GPL"); |