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1// SPDX-License-Identifier: GPL-2.02/*3 * I2C access driver for TI TPS65224/TPS6594/TPS6593/LP8764 PMICs4 *5 * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/6 */7 8#include <linux/crc8.h>9#include <linux/i2c.h>10#include <linux/module.h>11#include <linux/mod_devicetable.h>12#include <linux/of_device.h>13#include <linux/regmap.h>14 15#include <linux/mfd/tps6594.h>16 17static bool enable_crc;18module_param(enable_crc, bool, 0444);19MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");20 21DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);22 23static int tps6594_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)24{25 int ret = i2c_transfer(adap, msgs, num);26 27 if (ret == num)28 return 0;29 else if (ret < 0)30 return ret;31 else32 return -EIO;33}34 35static int tps6594_i2c_reg_read_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 *val)36{37 struct i2c_msg msgs[2];38 u8 buf_rx[] = { 0, 0 };39 /* I2C address = I2C base address + Page index */40 const u8 addr = client->addr + page;41 /*42 * CRC is calculated from every bit included in the protocol43 * except the ACK bits from the target. Byte stream is:44 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 045 * - B1: reg46 * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 147 * - B3: val48 * - B4: CRC from B0-B1-B2-B349 */50 u8 crc_data[] = { addr << 1, reg, addr << 1 | 1, 0 };51 int ret;52 53 /* Write register */54 msgs[0].addr = addr;55 msgs[0].flags = 0;56 msgs[0].len = 1;57 msgs[0].buf = ®58 59 /* Read data and CRC */60 msgs[1].addr = msgs[0].addr;61 msgs[1].flags = I2C_M_RD;62 msgs[1].len = 2;63 msgs[1].buf = buf_rx;64 65 ret = tps6594_i2c_transfer(client->adapter, msgs, 2);66 if (ret < 0)67 return ret;68 69 crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0];70 if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE))71 return -EIO;72 73 return ret;74}75 76static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val)77{78 struct i2c_msg msg;79 u8 buf[] = { reg, val, 0 };80 /* I2C address = I2C base address + Page index */81 const u8 addr = client->addr + page;82 /*83 * CRC is calculated from every bit included in the protocol84 * except the ACK bits from the target. Byte stream is:85 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 086 * - B1: reg87 * - B2: val88 * - B3: CRC from B0-B1-B289 */90 const u8 crc_data[] = { addr << 1, reg, val };91 92 /* Write register, data and CRC */93 msg.addr = addr;94 msg.flags = client->flags & I2C_M_TEN;95 msg.len = sizeof(buf);96 msg.buf = buf;97 98 buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE);99 100 return tps6594_i2c_transfer(client->adapter, &msg, 1);101}102 103static int tps6594_i2c_read(void *context, const void *reg_buf, size_t reg_size,104 void *val_buf, size_t val_size)105{106 struct i2c_client *client = context;107 struct tps6594 *tps = i2c_get_clientdata(client);108 struct i2c_msg msgs[2];109 const u8 *reg_bytes = reg_buf;110 u8 *val_bytes = val_buf;111 const u8 page = reg_bytes[1];112 u8 reg = reg_bytes[0];113 int ret = 0;114 int i;115 116 if (tps->use_crc) {117 /*118 * Auto-increment feature does not support CRC protocol.119 * Converts the bulk read operation into a series of single read operations.120 */121 for (i = 0 ; ret == 0 && i < val_size ; i++)122 ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i);123 124 return ret;125 }126 127 /* Write register: I2C address = I2C base address + Page index */128 msgs[0].addr = client->addr + page;129 msgs[0].flags = 0;130 msgs[0].len = 1;131 msgs[0].buf = ®132 133 /* Read data */134 msgs[1].addr = msgs[0].addr;135 msgs[1].flags = I2C_M_RD;136 msgs[1].len = val_size;137 msgs[1].buf = val_bytes;138 139 return tps6594_i2c_transfer(client->adapter, msgs, 2);140}141 142static int tps6594_i2c_write(void *context, const void *data, size_t count)143{144 struct i2c_client *client = context;145 struct tps6594 *tps = i2c_get_clientdata(client);146 struct i2c_msg msg;147 const u8 *bytes = data;148 u8 *buf;149 const u8 page = bytes[1];150 const u8 reg = bytes[0];151 int ret = 0;152 int i;153 154 if (tps->use_crc) {155 /*156 * Auto-increment feature does not support CRC protocol.157 * Converts the bulk write operation into a series of single write operations.158 */159 for (i = 0 ; ret == 0 && i < count - 2 ; i++)160 ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]);161 162 return ret;163 }164 165 /* Setup buffer: page byte is not sent */166 buf = kzalloc(--count, GFP_KERNEL);167 if (!buf)168 return -ENOMEM;169 170 buf[0] = reg;171 for (i = 0 ; i < count - 1 ; i++)172 buf[i + 1] = bytes[i + 2];173 174 /* Write register and data: I2C address = I2C base address + Page index */175 msg.addr = client->addr + page;176 msg.flags = client->flags & I2C_M_TEN;177 msg.len = count;178 msg.buf = buf;179 180 ret = tps6594_i2c_transfer(client->adapter, &msg, 1);181 182 kfree(buf);183 return ret;184}185 186static struct regmap_config tps6594_i2c_regmap_config = {187 .reg_bits = 16,188 .val_bits = 8,189 .max_register = TPS6594_REG_DWD_FAIL_CNT_REG,190 .volatile_table = &tps6594_volatile_table,191 .read = tps6594_i2c_read,192 .write = tps6594_i2c_write,193};194 195static const struct of_device_id tps6594_i2c_of_match_table[] = {196 { .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },197 { .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },198 { .compatible = "ti,lp8764-q1", .data = (void *)LP8764, },199 { .compatible = "ti,tps65224-q1", .data = (void *)TPS65224, },200 {}201};202MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table);203 204static int tps6594_i2c_probe(struct i2c_client *client)205{206 struct device *dev = &client->dev;207 struct tps6594 *tps;208 const struct of_device_id *match;209 210 tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);211 if (!tps)212 return -ENOMEM;213 214 i2c_set_clientdata(client, tps);215 216 tps->dev = dev;217 tps->reg = client->addr;218 tps->irq = client->irq;219 220 match = of_match_device(tps6594_i2c_of_match_table, dev);221 if (!match)222 return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");223 tps->chip_id = (unsigned long)match->data;224 225 if (tps->chip_id == TPS65224)226 tps6594_i2c_regmap_config.volatile_table = &tps65224_volatile_table;227 228 tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config);229 if (IS_ERR(tps->regmap))230 return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");231 232 crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL);233 234 return tps6594_device_init(tps, enable_crc);235}236 237static struct i2c_driver tps6594_i2c_driver = {238 .driver = {239 .name = "tps6594",240 .of_match_table = tps6594_i2c_of_match_table,241 },242 .probe = tps6594_i2c_probe,243};244module_i2c_driver(tps6594_i2c_driver);245 246MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");247MODULE_DESCRIPTION("I2C Interface Driver for TPS65224, TPS6594/3, and LP8764");248MODULE_LICENSE("GPL");249