tps6594-i2c.c

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