drivers/mfd/tps6594-i2c.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * I2C access driver for TI TPS6594/TPS6593/LP8764 PMICs
  *
  * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
  */

 #include <linux/crc8.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>

 #include <linux/mfd/tps6594.h>

 static bool enable_crc;
 module_param(enable_crc, bool, 0444);
 MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");

 DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);

 static int tps6594_i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 {
 	int ret = i2c_transfer(adap, msgs, num);

 	if (ret == num)
 		return 0;
 	else if (ret < 0)
 		return ret;
 	else
 		return -EIO;
 }

 static int tps6594_i2c_reg_read_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 *val)
 {
 	struct i2c_msg msgs[2];
 	u8 buf_rx[] = { 0, 0 };
 	/* I2C address = I2C base address + Page index */
 	const u8 addr = client->addr + page;
 	/*
 	 * CRC is calculated from every bit included in the protocol
 	 * except the ACK bits from the target. Byte stream is:
 	 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
 	 * - B1: reg
 	 * - B2: (I2C_addr_7bits << 1) | RD_bit, with RD_bit = 1
 	 * - B3: val
 	 * - B4: CRC from B0-B1-B2-B3
 	 */
 	u8 crc_data[] = { addr << 1, reg, addr << 1 | 1, 0 };
 	int ret;

 	/* Write register */
 	msgs[0].addr = addr;
 	msgs[0].flags = 0;
 	msgs[0].len = 1;
 	msgs[0].buf = &reg;

 	/* Read data and CRC */
 	msgs[1].addr = msgs[0].addr;
 	msgs[1].flags = I2C_M_RD;
 	msgs[1].len = 2;
 	msgs[1].buf = buf_rx;

 	ret = tps6594_i2c_transfer(client->adapter, msgs, 2);
 	if (ret < 0)
 		return ret;

 	crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0];
 	if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE))
 		return -EIO;

 	return ret;
 }

 static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val)
 {
 	struct i2c_msg msg;
 	u8 buf[] = { reg, val, 0 };
 	/* I2C address = I2C base address + Page index */
 	const u8 addr = client->addr + page;
 	/*
 	 * CRC is calculated from every bit included in the protocol
 	 * except the ACK bits from the target. Byte stream is:
 	 * - B0: (I2C_addr_7bits << 1) | WR_bit, with WR_bit = 0
 	 * - B1: reg
 	 * - B2: val
 	 * - B3: CRC from B0-B1-B2
 	 */
 	const u8 crc_data[] = { addr << 1, reg, val };

 	/* Write register, data and CRC */
 	msg.addr = addr;
 	msg.flags = client->flags & I2C_M_TEN;
 	msg.len = sizeof(buf);
 	msg.buf = buf;

 	buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE);

 	return tps6594_i2c_transfer(client->adapter, &msg, 1);
 }

 static int tps6594_i2c_read(void *context, const void *reg_buf, size_t reg_size,
 			    void *val_buf, size_t val_size)
 {
 	struct i2c_client *client = context;
 	struct tps6594 *tps = i2c_get_clientdata(client);
 	struct i2c_msg msgs[2];
 	const u8 *reg_bytes = reg_buf;
 	u8 *val_bytes = val_buf;
 	const u8 page = reg_bytes[1];
 	u8 reg = reg_bytes[0];
 	int ret = 0;
 	int i;

 	if (tps->use_crc) {
 		/*
 		 * Auto-increment feature does not support CRC protocol.
 		 * Converts the bulk read operation into a series of single read operations.
 		 */
 		for (i = 0 ; ret == 0 && i < val_size ; i++)
 			ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i);

 		return ret;
 	}

 	/* Write register: I2C address = I2C base address + Page index */
 	msgs[0].addr = client->addr + page;
 	msgs[0].flags = 0;
 	msgs[0].len = 1;
 	msgs[0].buf = &reg;

 	/* Read data */
 	msgs[1].addr = msgs[0].addr;
 	msgs[1].flags = I2C_M_RD;
 	msgs[1].len = val_size;
 	msgs[1].buf = val_bytes;

 	return tps6594_i2c_transfer(client->adapter, msgs, 2);
 }

 static int tps6594_i2c_write(void *context, const void *data, size_t count)
 {
 	struct i2c_client *client = context;
 	struct tps6594 *tps = i2c_get_clientdata(client);
 	struct i2c_msg msg;
 	const u8 *bytes = data;
 	u8 *buf;
 	const u8 page = bytes[1];
 	const u8 reg = bytes[0];
 	int ret = 0;
 	int i;

 	if (tps->use_crc) {
 		/*
 		 * Auto-increment feature does not support CRC protocol.
 		 * Converts the bulk write operation into a series of single write operations.
 		 */
 		for (i = 0 ; ret == 0 && i < count - 2 ; i++)
 			ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]);

 		return ret;
 	}

 	/* Setup buffer: page byte is not sent */
 	buf = kzalloc(--count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	buf[0] = reg;
 	for (i = 0 ; i < count - 1 ; i++)
 		buf[i + 1] = bytes[i + 2];

 	/* Write register and data: I2C address = I2C base address + Page index */
 	msg.addr = client->addr + page;
 	msg.flags = client->flags & I2C_M_TEN;
 	msg.len = count;
 	msg.buf = buf;

 	ret = tps6594_i2c_transfer(client->adapter, &msg, 1);

 	kfree(buf);
 	return ret;
 }

 static const struct regmap_config tps6594_i2c_regmap_config = {
 	.reg_bits = 16,
 	.val_bits = 8,
 	.max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
 	.volatile_reg = tps6594_is_volatile_reg,
 	.read = tps6594_i2c_read,
 	.write = tps6594_i2c_write,
 };

 static const struct of_device_id tps6594_i2c_of_match_table[] = {
 	{ .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
 	{ .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
 	{ .compatible = "ti,lp8764-q1",  .data = (void *)LP8764,  },
 	{}
 };
 MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table);

 static int tps6594_i2c_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct tps6594 *tps;
 	const struct of_device_id *match;

 	tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
 	if (!tps)
 		return -ENOMEM;

 	i2c_set_clientdata(client, tps);

 	tps->dev = dev;
 	tps->reg = client->addr;
 	tps->irq = client->irq;

 	tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config);
 	if (IS_ERR(tps->regmap))
 		return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");

 	match = of_match_device(tps6594_i2c_of_match_table, dev);
 	if (!match)
 		return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
 	tps->chip_id = (unsigned long)match->data;

 	crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL);

 	return tps6594_device_init(tps, enable_crc);
 }

 static struct i2c_driver tps6594_i2c_driver = {
 	.driver	= {
 		.name = "tps6594",
 		.of_match_table = tps6594_i2c_of_match_table,
 	},
 	.probe = tps6594_i2c_probe,
 };
 module_i2c_driver(tps6594_i2c_driver);

 MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
 MODULE_DESCRIPTION("TPS6594 I2C Interface Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* I2C access driver for TI TPS6594/TPS6593/LP8764 PMICs
	*
	* Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
	*/

	#include <linux/crc8.h>
	#include <linux/i2c.h>
	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/of_device.h>
	#include <linux/regmap.h>

	#include <linux/mfd/tps6594.h>

	static bool enable_crc;
	module_param(enable_crc, bool, 0444);
	MODULE_PARM_DESC(enable_crc, "Enable CRC feature for I2C interface");

	DECLARE_CRC8_TABLE(tps6594_i2c_crc_table);

	static int tps6594_i2c_transfer(struct i2c_adapter adap, struct i2c_msg msgs, int num)
	{
	int ret = i2c_transfer(adap, msgs, num);

	if (ret == num)
	return 0;
	else if (ret < 0)
	return ret;
	else
	return -EIO;
	}

	static int tps6594_i2c_reg_read_with_crc(struct i2c_client client, u8 page, u8 reg, u8 val)
	{
	struct i2c_msg msgs[2];
	u8 buf_rx[] = { 0, 0 };
	/* I2C address = I2C base address + Page index */
	const u8 addr = client->addr + page;
	/*
	* CRC is calculated from every bit included in the protocol
	* except the ACK bits from the target. Byte stream is:
	* - B0: (I2C_addr_7bits << 1) \| WR_bit, with WR_bit = 0
	* - B1: reg
	* - B2: (I2C_addr_7bits << 1) \| RD_bit, with RD_bit = 1
	* - B3: val
	* - B4: CRC from B0-B1-B2-B3
	*/
	u8 crc_data[] = { addr << 1, reg, addr << 1 \| 1, 0 };
	int ret;

	/* Write register */
	msgs[0].addr = addr;
	msgs[0].flags = 0;
	msgs[0].len = 1;
	msgs[0].buf = ®

	/* Read data and CRC */
	msgs[1].addr = msgs[0].addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = 2;
	msgs[1].buf = buf_rx;

	ret = tps6594_i2c_transfer(client->adapter, msgs, 2);
	if (ret < 0)
	return ret;

	crc_data[sizeof(crc_data) - 1] = *val = buf_rx[0];
	if (buf_rx[1] != crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE))
	return -EIO;

	return ret;
	}

	static int tps6594_i2c_reg_write_with_crc(struct i2c_client *client, u8 page, u8 reg, u8 val)
	{
	struct i2c_msg msg;
	u8 buf[] = { reg, val, 0 };
	/* I2C address = I2C base address + Page index */
	const u8 addr = client->addr + page;
	/*
	* CRC is calculated from every bit included in the protocol
	* except the ACK bits from the target. Byte stream is:
	* - B0: (I2C_addr_7bits << 1) \| WR_bit, with WR_bit = 0
	* - B1: reg
	* - B2: val
	* - B3: CRC from B0-B1-B2
	*/
	const u8 crc_data[] = { addr << 1, reg, val };

	/* Write register, data and CRC */
	msg.addr = addr;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = sizeof(buf);
	msg.buf = buf;

	buf[msg.len - 1] = crc8(tps6594_i2c_crc_table, crc_data, sizeof(crc_data), CRC8_INIT_VALUE);

	return tps6594_i2c_transfer(client->adapter, &msg, 1);
	}

	static int tps6594_i2c_read(void context, const void reg_buf, size_t reg_size,
	void *val_buf, size_t val_size)
	{
	struct i2c_client *client = context;
	struct tps6594 *tps = i2c_get_clientdata(client);
	struct i2c_msg msgs[2];
	const u8 *reg_bytes = reg_buf;
	u8 *val_bytes = val_buf;
	const u8 page = reg_bytes[1];
	u8 reg = reg_bytes[0];
	int ret = 0;
	int i;

	if (tps->use_crc) {
	/*
	* Auto-increment feature does not support CRC protocol.
	* Converts the bulk read operation into a series of single read operations.
	*/
	for (i = 0 ; ret == 0 && i < val_size ; i++)
	ret = tps6594_i2c_reg_read_with_crc(client, page, reg + i, val_bytes + i);

	return ret;
	}

	/* Write register: I2C address = I2C base address + Page index */
	msgs[0].addr = client->addr + page;
	msgs[0].flags = 0;
	msgs[0].len = 1;
	msgs[0].buf = ®

	/* Read data */
	msgs[1].addr = msgs[0].addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = val_size;
	msgs[1].buf = val_bytes;

	return tps6594_i2c_transfer(client->adapter, msgs, 2);
	}

	static int tps6594_i2c_write(void context, const void data, size_t count)
	{
	struct i2c_client *client = context;
	struct tps6594 *tps = i2c_get_clientdata(client);
	struct i2c_msg msg;
	const u8 *bytes = data;
	u8 *buf;
	const u8 page = bytes[1];
	const u8 reg = bytes[0];
	int ret = 0;
	int i;

	if (tps->use_crc) {
	/*
	* Auto-increment feature does not support CRC protocol.
	* Converts the bulk write operation into a series of single write operations.
	*/
	for (i = 0 ; ret == 0 && i < count - 2 ; i++)
	ret = tps6594_i2c_reg_write_with_crc(client, page, reg + i, bytes[i + 2]);

	return ret;
	}

	/* Setup buffer: page byte is not sent */
	buf = kzalloc(--count, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	buf[0] = reg;
	for (i = 0 ; i < count - 1 ; i++)
	buf[i + 1] = bytes[i + 2];

	/* Write register and data: I2C address = I2C base address + Page index */
	msg.addr = client->addr + page;
	msg.flags = client->flags & I2C_M_TEN;
	msg.len = count;
	msg.buf = buf;

	ret = tps6594_i2c_transfer(client->adapter, &msg, 1);

	kfree(buf);
	return ret;
	}

	static const struct regmap_config tps6594_i2c_regmap_config = {
	.reg_bits = 16,
	.val_bits = 8,
	.max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
	.volatile_reg = tps6594_is_volatile_reg,
	.read = tps6594_i2c_read,
	.write = tps6594_i2c_write,
	};

	static const struct of_device_id tps6594_i2c_of_match_table[] = {
	{ .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
	{ .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
	{ .compatible = "ti,lp8764-q1", .data = (void *)LP8764, },
	{}
	};
	MODULE_DEVICE_TABLE(of, tps6594_i2c_of_match_table);

	static int tps6594_i2c_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct tps6594 *tps;
	const struct of_device_id *match;

	tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
	if (!tps)
	return -ENOMEM;

	i2c_set_clientdata(client, tps);

	tps->dev = dev;
	tps->reg = client->addr;
	tps->irq = client->irq;

	tps->regmap = devm_regmap_init(dev, NULL, client, &tps6594_i2c_regmap_config);
	if (IS_ERR(tps->regmap))
	return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");

	match = of_match_device(tps6594_i2c_of_match_table, dev);
	if (!match)
	return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
	tps->chip_id = (unsigned long)match->data;

	crc8_populate_msb(tps6594_i2c_crc_table, TPS6594_CRC8_POLYNOMIAL);

	return tps6594_device_init(tps, enable_crc);
	}

	static struct i2c_driver tps6594_i2c_driver = {
	.driver = {
	.name = "tps6594",
	.of_match_table = tps6594_i2c_of_match_table,
	},
	.probe = tps6594_i2c_probe,
	};
	module_i2c_driver(tps6594_i2c_driver);

	MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
	MODULE_DESCRIPTION("TPS6594 I2C Interface Driver");
	MODULE_LICENSE("GPL");