1// SPDX-License-Identifier: GPL-2.0 2/* 3 * I2C access driver for TI TPS6594/TPS6593/LP8764 PMICs 4 * 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 else 32 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 protocol 43 * except the ACK bits from the target. Byte stream is: 44 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0 45 * - B1: reg 46 * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 1 47 * - B3: val 48 * - B4: CRC from B0-B1-B2-B3 49 */ 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 protocol 84 * except the ACK bits from the target. Byte stream is: 85 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0 86 * - B1: reg 87 * - B2: val 88 * - B3: CRC from B0-B1-B2 89 */ 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 const 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_reg = tps6594_is_volatile_reg, 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 {} 200}; 201MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table); 202 203static int tps6594_i2c_probe(struct i2c_client *client) 204{ 205 struct device *dev = &client->dev; 206 struct tps6594 *tps; 207 const struct of_device_id *match; 208 209 tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL); 210 if (!tps) 211 return -ENOMEM; 212 213 i2c_set_clientdata(client, tps); 214 215 tps->dev = dev; 216 tps->reg = client->addr; 217 tps->irq = client->irq; 218 219 tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config); 220 if (IS_ERR(tps->regmap)) 221 return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n"); 222 223 match = of_match_device(tps6594_i2c_of_match_table, dev); 224 if (!match) 225 return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n"); 226 tps->chip_id = (unsigned long)match->data; 227 228 crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL); 229 230 return tps6594_device_init(tps, enable_crc); 231} 232 233static struct i2c_driver tps6594_i2c_driver = { 234 .driver = { 235 .name = "tps6594", 236 .of_match_table = tps6594_i2c_of_match_table, 237 }, 238 .probe = tps6594_i2c_probe, 239}; 240module_i2c_driver(tps6594_i2c_driver); 241 242MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>"); 243MODULE_DESCRIPTION("TPS6594 I2C Interface Driver"); 244MODULE_LICENSE("GPL"); 245