1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * I2C access driver for the following TI PMICs:
4 * - LP8764
5 * - TPS65224
6 * - TPS652G1
7 * - TPS6593
8 * - TPS6594
9 *
10 * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
11 */
12
13 #include <linux/crc8.h>
14 #include <linux/i2c.h>
15 #include <linux/module.h>
16 #include <linux/of_device.h>
17 #include <linux/regmap.h>
18
19 #include <linux/mfd/tps6594.h>
20
21 static bool enable_crc;
22 module_param(enable_crc, bool, 0444);
23 MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");
24
25 DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);
26
tps6594_i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)27 static int tps6594_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
28 {
29 int ret = i2c_transfer(adap, msgs, num);
30
31 if (ret == num)
32 return 0;
33 else if (ret < 0)
34 return ret;
35 else
36 return -EIO;
37 }
38
tps6594_i2c_reg_read_with_crc(struct i2c_client * client,u8 page,u8 reg,u8 * val)39 static int tps6594_i2c_reg_read_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 *val)
40 {
41 struct i2c_msg msgs[2];
42 u8 buf_rx[] = { 0, 0 };
43 /* I2C address = I2C base address + Page index */
44 const u8 addr = client->addr + page;
45 /*
46 * CRC is calculated from every bit included in the protocol
47 * except the ACK bits from the target. Byte stream is:
48 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
49 * - B1: reg
50 * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 1
51 * - B3: val
52 * - B4: CRC from B0-B1-B2-B3
53 */
54 u8 crc_data[] = { addr << 1, reg, addr << 1 | 1, 0 };
55 int ret;
56
57 /* Write register */
58 msgs[0].addr = addr;
59 msgs[0].flags = 0;
60 msgs[0].len = 1;
61 msgs[0].buf = ®
62
63 /* Read data and CRC */
64 msgs[1].addr = msgs[0].addr;
65 msgs[1].flags = I2C_M_RD;
66 msgs[1].len = 2;
67 msgs[1].buf = buf_rx;
68
69 ret = tps6594_i2c_transfer(client->adapter, msgs, 2);
70 if (ret < 0)
71 return ret;
72
73 crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0];
74 if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE))
75 return -EIO;
76
77 return ret;
78 }
79
tps6594_i2c_reg_write_with_crc(struct i2c_client * client,u8 page,u8 reg,u8 val)80 static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val)
81 {
82 struct i2c_msg msg;
83 u8 buf[] = { reg, val, 0 };
84 /* I2C address = I2C base address + Page index */
85 const u8 addr = client->addr + page;
86 /*
87 * CRC is calculated from every bit included in the protocol
88 * except the ACK bits from the target. Byte stream is:
89 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
90 * - B1: reg
91 * - B2: val
92 * - B3: CRC from B0-B1-B2
93 */
94 const u8 crc_data[] = { addr << 1, reg, val };
95
96 /* Write register, data and CRC */
97 msg.addr = addr;
98 msg.flags = client->flags & I2C_M_TEN;
99 msg.len = sizeof(buf);
100 msg.buf = buf;
101
102 buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE);
103
104 return tps6594_i2c_transfer(client->adapter, &msg, 1);
105 }
106
tps6594_i2c_read(void * context,const void * reg_buf,size_t reg_size,void * val_buf,size_t val_size)107 static int tps6594_i2c_read(void *context, const void *reg_buf, size_t reg_size,
108 void *val_buf, size_t val_size)
109 {
110 struct i2c_client *client = context;
111 struct tps6594 *tps = i2c_get_clientdata(client);
112 struct i2c_msg msgs[2];
113 const u8 *reg_bytes = reg_buf;
114 u8 *val_bytes = val_buf;
115 const u8 page = reg_bytes[1];
116 u8 reg = reg_bytes[0];
117 int ret = 0;
118 int i;
119
120 if (tps->use_crc) {
121 /*
122 * Auto-increment feature does not support CRC protocol.
123 * Converts the bulk read operation into a series of single read operations.
124 */
125 for (i = 0 ; ret == 0 && i < val_size ; i++)
126 ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i);
127
128 return ret;
129 }
130
131 /* Write register: I2C address = I2C base address + Page index */
132 msgs[0].addr = client->addr + page;
133 msgs[0].flags = 0;
134 msgs[0].len = 1;
135 msgs[0].buf = ®
136
137 /* Read data */
138 msgs[1].addr = msgs[0].addr;
139 msgs[1].flags = I2C_M_RD;
140 msgs[1].len = val_size;
141 msgs[1].buf = val_bytes;
142
143 return tps6594_i2c_transfer(client->adapter, msgs, 2);
144 }
145
tps6594_i2c_write(void * context,const void * data,size_t count)146 static int tps6594_i2c_write(void *context, const void *data, size_t count)
147 {
148 struct i2c_client *client = context;
149 struct tps6594 *tps = i2c_get_clientdata(client);
150 struct i2c_msg msg;
151 const u8 *bytes = data;
152 u8 *buf;
153 const u8 page = bytes[1];
154 const u8 reg = bytes[0];
155 int ret = 0;
156 int i;
157
158 if (tps->use_crc) {
159 /*
160 * Auto-increment feature does not support CRC protocol.
161 * Converts the bulk write operation into a series of single write operations.
162 */
163 for (i = 0 ; ret == 0 && i < count - 2 ; i++)
164 ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]);
165
166 return ret;
167 }
168
169 /* Setup buffer: page byte is not sent */
170 buf = kzalloc(--count, GFP_KERNEL);
171 if (!buf)
172 return -ENOMEM;
173
174 buf[0] = reg;
175 for (i = 0 ; i < count - 1 ; i++)
176 buf[i + 1] = bytes[i + 2];
177
178 /* Write register and data: I2C address = I2C base address + Page index */
179 msg.addr = client->addr + page;
180 msg.flags = client->flags & I2C_M_TEN;
181 msg.len = count;
182 msg.buf = buf;
183
184 ret = tps6594_i2c_transfer(client->adapter, &msg, 1);
185
186 kfree(buf);
187 return ret;
188 }
189
190 static struct regmap_config tps6594_i2c_regmap_config = {
191 .reg_bits = 16,
192 .val_bits = 8,
193 .max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
194 .volatile_table = &tps6594_volatile_table,
195 .read = tps6594_i2c_read,
196 .write = tps6594_i2c_write,
197 };
198
199 static const struct of_device_id tps6594_i2c_of_match_table[] = {
200 { .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
201 { .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
202 { .compatible = "ti,lp8764-q1", .data = (void *)LP8764, },
203 { .compatible = "ti,tps65224-q1", .data = (void *)TPS65224, },
204 { .compatible = "ti,tps652g1", .data = (void *)TPS652G1, },
205 {}
206 };
207 MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table);
208
tps6594_i2c_probe(struct i2c_client * client)209 static int tps6594_i2c_probe(struct i2c_client *client)
210 {
211 struct device *dev = &client->dev;
212 struct tps6594 *tps;
213 const struct of_device_id *match;
214
215 tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
216 if (!tps)
217 return -ENOMEM;
218
219 i2c_set_clientdata(client, tps);
220
221 tps->dev = dev;
222 tps->reg = client->addr;
223 tps->irq = client->irq;
224
225 match = of_match_device(tps6594_i2c_of_match_table, dev);
226 if (!match)
227 return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
228 tps->chip_id = (unsigned long)match->data;
229
230 if (tps->chip_id == TPS65224 || tps->chip_id == TPS652G1)
231 tps6594_i2c_regmap_config.volatile_table = &tps65224_volatile_table;
232
233 tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config);
234 if (IS_ERR(tps->regmap))
235 return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");
236
237 crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL);
238
239 return tps6594_device_init(tps, enable_crc);
240 }
241
242 static struct i2c_driver tps6594_i2c_driver = {
243 .driver = {
244 .name = "tps6594",
245 .of_match_table = tps6594_i2c_of_match_table,
246 },
247 .probe = tps6594_i2c_probe,
248 };
249 module_i2c_driver(tps6594_i2c_driver);
250
251 MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
252 MODULE_DESCRIPTION("I2C Interface Driver for TPS65224, TPS6594/3, and LP8764");
253 MODULE_LICENSE("GPL");
254