drivers/mfd/tps6594-i2c.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * I2C access driver for TI TPS65224/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
  17 static bool enable_crc;
  18 module_param(enable_crc, bool, 0444);
  19 MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");
  20
  21 DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);
  22
  23 static 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
  35 static 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 = &reg;
  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
  76 static 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
 103 static 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 = &reg;
 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
 142 static 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
 186 static 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
 195 static 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 };
 202 MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table);
 203
 204 static 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
 237 static 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 };
 244 module_i2c_driver(tps6594_i2c_driver);
 245
 246 MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
 247 MODULE_DESCRIPTION("I2C Interface Driver for TPS65224, TPS6594/3, and LP8764");
 248 MODULE_LICENSE("GPL");