drivers/hwmon/pmbus/max20730.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Driver for MAX20730, MAX20734, and MAX20743 Integrated, Step-Down
  * Switching Regulators
  *
  * Copyright 2019 Google LLC.
  */

 #include <linux/bits.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of_device.h>
 #include <linux/pmbus.h>
 #include <linux/util_macros.h>
 #include "pmbus.h"

 enum chips {
 	max20730,
 	max20734,
 	max20743
 };

 struct max20730_data {
 	enum chips id;
 	struct pmbus_driver_info info;
 	struct mutex lock;	/* Used to protect against parallel writes */
 	u16 mfr_devset1;
 };

 #define to_max20730_data(x)  container_of(x, struct max20730_data, info)

 #define MAX20730_MFR_DEVSET1	0xd2

 /*
  * Convert discreet value to direct data format. Strictly speaking, all passed
  * values are constants, so we could do that calculation manually. On the
  * downside, that would make the driver more difficult to maintain, so lets
  * use this approach.
  */
 static u16 val_to_direct(int v, enum pmbus_sensor_classes class,
 			 const struct pmbus_driver_info *info)
 {
 	int R = info->R[class] - 3;	/* take milli-units into account */
 	int b = info->b[class] * 1000;
 	long d;

 	d = v * info->m[class] + b;
 	/*
 	 * R < 0 is true for all callers, so we don't need to bother
 	 * about the R > 0 case.
 	 */
 	while (R < 0) {
 		d = DIV_ROUND_CLOSEST(d, 10);
 		R++;
 	}
 	return (u16)d;
 }

 static long direct_to_val(u16 w, enum pmbus_sensor_classes class,
 			  const struct pmbus_driver_info *info)
 {
 	int R = info->R[class] - 3;
 	int b = info->b[class] * 1000;
 	int m = info->m[class];
 	long d = (s16)w;

 	if (m == 0)
 		return 0;

 	while (R < 0) {
 		d *= 10;
 		R++;
 	}
 	d = (d - b) / m;
 	return d;
 }

 static u32 max_current[][5] = {
 	[max20730] = { 13000, 16600, 20100, 23600 },
 	[max20734] = { 21000, 27000, 32000, 38000 },
 	[max20743] = { 18900, 24100, 29200, 34100 },
 };

 static int max20730_read_word_data(struct i2c_client *client, int page,
 				   int phase, int reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 	const struct max20730_data *data = to_max20730_data(info);
 	int ret = 0;
 	u32 max_c;

 	switch (reg) {
 	case PMBUS_OT_FAULT_LIMIT:
 		switch ((data->mfr_devset1 >> 11) & 0x3) {
 		case 0x0:
 			ret = val_to_direct(150000, PSC_TEMPERATURE, info);
 			break;
 		case 0x1:
 			ret = val_to_direct(130000, PSC_TEMPERATURE, info);
 			break;
 		default:
 			ret = -ENODATA;
 			break;
 		}
 		break;
 	case PMBUS_IOUT_OC_FAULT_LIMIT:
 		max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3];
 		ret = val_to_direct(max_c, PSC_CURRENT_OUT, info);
 		break;
 	default:
 		ret = -ENODATA;
 		break;
 	}
 	return ret;
 }

 static int max20730_write_word_data(struct i2c_client *client, int page,
 				    int reg, u16 word)
 {
 	struct pmbus_driver_info *info;
 	struct max20730_data *data;
 	u16 devset1;
 	int ret = 0;
 	int idx;

 	info = (struct pmbus_driver_info *)pmbus_get_driver_info(client);
 	data = to_max20730_data(info);

 	mutex_lock(&data->lock);
 	devset1 = data->mfr_devset1;

 	switch (reg) {
 	case PMBUS_OT_FAULT_LIMIT:
 		devset1 &= ~(BIT(11) | BIT(12));
 		if (direct_to_val(word, PSC_TEMPERATURE, info) < 140000)
 			devset1 |= BIT(11);
 		break;
 	case PMBUS_IOUT_OC_FAULT_LIMIT:
 		devset1 &= ~(BIT(5) | BIT(6));

 		idx = find_closest(direct_to_val(word, PSC_CURRENT_OUT, info),
 				   max_current[data->id], 4);
 		devset1 |= (idx << 5);
 		break;
 	default:
 		ret = -ENODATA;
 		break;
 	}

 	if (!ret && devset1 != data->mfr_devset1) {
 		ret = i2c_smbus_write_word_data(client, MAX20730_MFR_DEVSET1,
 						devset1);
 		if (!ret) {
 			data->mfr_devset1 = devset1;
 			pmbus_clear_cache(client);
 		}
 	}
 	mutex_unlock(&data->lock);
 	return ret;
 }

 static const struct pmbus_driver_info max20730_info[] = {
 	[max20730] = {
 		.pages = 1,
 		.read_word_data = max20730_read_word_data,
 		.write_word_data = max20730_write_word_data,

 		/* Source : Maxim AN6042 */
 		.format[PSC_TEMPERATURE] = direct,
 		.m[PSC_TEMPERATURE] = 21,
 		.b[PSC_TEMPERATURE] = 5887,
 		.R[PSC_TEMPERATURE] = -1,

 		.format[PSC_VOLTAGE_IN] = direct,
 		.m[PSC_VOLTAGE_IN] = 3609,
 		.b[PSC_VOLTAGE_IN] = 0,
 		.R[PSC_VOLTAGE_IN] = -2,

 		/*
 		 * Values in the datasheet are adjusted for temperature and
 		 * for the relationship between Vin and Vout.
 		 * Unfortunately, the data sheet suggests that Vout measurement
 		 * may be scaled with a resistor array. This is indeed the case
 		 * at least on the evaulation boards. As a result, any in-driver
 		 * adjustments would either be wrong or require elaborate means
 		 * to configure the scaling. Instead of doing that, just report
 		 * raw values and let userspace handle adjustments.
 		 */
 		.format[PSC_CURRENT_OUT] = direct,
 		.m[PSC_CURRENT_OUT] = 153,
 		.b[PSC_CURRENT_OUT] = 4976,
 		.R[PSC_CURRENT_OUT] = -1,

 		.format[PSC_VOLTAGE_OUT] = linear,

 		.func[0] = PMBUS_HAVE_VIN |
 			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
 			PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
 	},
 	[max20734] = {
 		.pages = 1,
 		.read_word_data = max20730_read_word_data,
 		.write_word_data = max20730_write_word_data,

 		/* Source : Maxim AN6209 */
 		.format[PSC_TEMPERATURE] = direct,
 		.m[PSC_TEMPERATURE] = 21,
 		.b[PSC_TEMPERATURE] = 5887,
 		.R[PSC_TEMPERATURE] = -1,

 		.format[PSC_VOLTAGE_IN] = direct,
 		.m[PSC_VOLTAGE_IN] = 3592,
 		.b[PSC_VOLTAGE_IN] = 0,
 		.R[PSC_VOLTAGE_IN] = -2,

 		.format[PSC_CURRENT_OUT] = direct,
 		.m[PSC_CURRENT_OUT] = 111,
 		.b[PSC_CURRENT_OUT] = 3461,
 		.R[PSC_CURRENT_OUT] = -1,

 		.format[PSC_VOLTAGE_OUT] = linear,

 		.func[0] = PMBUS_HAVE_VIN |
 			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
 			PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
 	},
 	[max20743] = {
 		.pages = 1,
 		.read_word_data = max20730_read_word_data,
 		.write_word_data = max20730_write_word_data,

 		/* Source : Maxim AN6042 */
 		.format[PSC_TEMPERATURE] = direct,
 		.m[PSC_TEMPERATURE] = 21,
 		.b[PSC_TEMPERATURE] = 5887,
 		.R[PSC_TEMPERATURE] = -1,

 		.format[PSC_VOLTAGE_IN] = direct,
 		.m[PSC_VOLTAGE_IN] = 3597,
 		.b[PSC_VOLTAGE_IN] = 0,
 		.R[PSC_VOLTAGE_IN] = -2,

 		.format[PSC_CURRENT_OUT] = direct,
 		.m[PSC_CURRENT_OUT] = 95,
 		.b[PSC_CURRENT_OUT] = 5014,
 		.R[PSC_CURRENT_OUT] = -1,

 		.format[PSC_VOLTAGE_OUT] = linear,

 		.func[0] = PMBUS_HAVE_VIN |
 			PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 			PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
 			PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
 	},
 };

 static int max20730_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
 	struct max20730_data *data;
 	enum chips chip_id;
 	int ret;

 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
 				     I2C_FUNC_SMBUS_READ_WORD_DATA |
 				     I2C_FUNC_SMBUS_BLOCK_DATA))
 		return -ENODEV;

 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
 	if (ret < 0) {
 		dev_err(&client->dev, "Failed to read Manufacturer ID\n");
 		return ret;
 	}
 	if (ret != 5 || strncmp(buf, "MAXIM", 5)) {
 		buf[ret] = '\0';
 		dev_err(dev, "Unsupported Manufacturer ID '%s'\n", buf);
 		return -ENODEV;
 	}

 	/*
 	 * The chips support reading PMBUS_MFR_MODEL. On both MAX20730
 	 * and MAX20734, reading it returns M20743. Presumably that is
 	 * the reason why the command is not documented. Unfortunately,
 	 * that means that there is no reliable means to detect the chip.
 	 * However, we can at least detect the chip series. Compare
 	 * the returned value against 'M20743' and bail out if there is
 	 * a mismatch. If that doesn't work for all chips, we may have
 	 * to remove this check.
 	 */
 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
 	if (ret < 0) {
 		dev_err(dev, "Failed to read Manufacturer Model\n");
 		return ret;
 	}
 	if (ret != 6 || strncmp(buf, "M20743", 6)) {
 		buf[ret] = '\0';
 		dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
 		return -ENODEV;
 	}

 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
 	if (ret < 0) {
 		dev_err(dev, "Failed to read Manufacturer Revision\n");
 		return ret;
 	}
 	if (ret != 1 || buf[0] != 'F') {
 		buf[ret] = '\0';
 		dev_err(dev, "Unsupported Manufacturer Revision '%s'\n", buf);
 		return -ENODEV;
 	}

 	if (client->dev.of_node)
 		chip_id = (enum chips)of_device_get_match_data(dev);
 	else
 		chip_id = id->driver_data;

 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 	data->id = chip_id;
 	mutex_init(&data->lock);
 	memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info));

 	ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
 	if (ret < 0)
 		return ret;
 	data->mfr_devset1 = ret;

 	return pmbus_do_probe(client, id, &data->info);
 }

 static const struct i2c_device_id max20730_id[] = {
 	{ "max20730", max20730 },
 	{ "max20734", max20734 },
 	{ "max20743", max20743 },
 	{ },
 };

 MODULE_DEVICE_TABLE(i2c, max20730_id);

 static const struct of_device_id max20730_of_match[] = {
 	{ .compatible = "maxim,max20730", .data = (void *)max20730 },
 	{ .compatible = "maxim,max20734", .data = (void *)max20734 },
 	{ .compatible = "maxim,max20743", .data = (void *)max20743 },
 	{ },
 };

 MODULE_DEVICE_TABLE(of, max20730_of_match);

 static struct i2c_driver max20730_driver = {
 	.driver = {
 		.name = "max20730",
 		.of_match_table = max20730_of_match,
 	},
 	.probe = max20730_probe,
 	.remove = pmbus_do_remove,
 	.id_table = max20730_id,
 };

 module_i2c_driver(max20730_driver);

 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 MODULE_DESCRIPTION("PMBus driver for Maxim MAX20730 / MAX20734 / MAX20743");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Driver for MAX20730, MAX20734, and MAX20743 Integrated, Step-Down
	* Switching Regulators
	*
	* Copyright 2019 Google LLC.
	*/

	#include <linux/bits.h>
	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of_device.h>
	#include <linux/pmbus.h>
	#include <linux/util_macros.h>
	#include "pmbus.h"

	enum chips {
	max20730,
	max20734,
	max20743
	};

	struct max20730_data {
	enum chips id;
	struct pmbus_driver_info info;
	struct mutex lock; /* Used to protect against parallel writes */
	u16 mfr_devset1;
	};

	#define to_max20730_data(x) container_of(x, struct max20730_data, info)

	#define MAX20730_MFR_DEVSET1 0xd2

	/*
	* Convert discreet value to direct data format. Strictly speaking, all passed
	* values are constants, so we could do that calculation manually. On the
	* downside, that would make the driver more difficult to maintain, so lets
	* use this approach.
	*/
	static u16 val_to_direct(int v, enum pmbus_sensor_classes class,
	const struct pmbus_driver_info *info)
	{
	int R = info->R[class] - 3; /* take milli-units into account */
	int b = info->b[class] * 1000;
	long d;

	d = v * info->m[class] + b;
	/*
	* R < 0 is true for all callers, so we don't need to bother
	* about the R > 0 case.
	*/
	while (R < 0) {
	d = DIV_ROUND_CLOSEST(d, 10);
	R++;
	}
	return (u16)d;
	}

	static long direct_to_val(u16 w, enum pmbus_sensor_classes class,
	const struct pmbus_driver_info *info)
	{
	int R = info->R[class] - 3;
	int b = info->b[class] * 1000;
	int m = info->m[class];
	long d = (s16)w;

	if (m == 0)
	return 0;

	while (R < 0) {
	d *= 10;
	R++;
	}
	d = (d - b) / m;
	return d;
	}

	static u32 max_current[][5] = {
	[max20730] = { 13000, 16600, 20100, 23600 },
	[max20734] = { 21000, 27000, 32000, 38000 },
	[max20743] = { 18900, 24100, 29200, 34100 },
	};

	static int max20730_read_word_data(struct i2c_client *client, int page,
	int phase, int reg)
	{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	const struct max20730_data *data = to_max20730_data(info);
	int ret = 0;
	u32 max_c;

	switch (reg) {
	case PMBUS_OT_FAULT_LIMIT:
	switch ((data->mfr_devset1 >> 11) & 0x3) {
	case 0x0:
	ret = val_to_direct(150000, PSC_TEMPERATURE, info);
	break;
	case 0x1:
	ret = val_to_direct(130000, PSC_TEMPERATURE, info);
	break;
	default:
	ret = -ENODATA;
	break;
	}
	break;
	case PMBUS_IOUT_OC_FAULT_LIMIT:
	max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3];
	ret = val_to_direct(max_c, PSC_CURRENT_OUT, info);
	break;
	default:
	ret = -ENODATA;
	break;
	}
	return ret;
	}

	static int max20730_write_word_data(struct i2c_client *client, int page,
	int reg, u16 word)
	{
	struct pmbus_driver_info *info;
	struct max20730_data *data;
	u16 devset1;
	int ret = 0;
	int idx;

	info = (struct pmbus_driver_info *)pmbus_get_driver_info(client);
	data = to_max20730_data(info);

	mutex_lock(&data->lock);
	devset1 = data->mfr_devset1;

	switch (reg) {
	case PMBUS_OT_FAULT_LIMIT:
	devset1 &= ~(BIT(11) \| BIT(12));
	if (direct_to_val(word, PSC_TEMPERATURE, info) < 140000)
	devset1 \|= BIT(11);
	break;
	case PMBUS_IOUT_OC_FAULT_LIMIT:
	devset1 &= ~(BIT(5) \| BIT(6));

	idx = find_closest(direct_to_val(word, PSC_CURRENT_OUT, info),
	max_current[data->id], 4);
	devset1 \|= (idx << 5);
	break;
	default:
	ret = -ENODATA;
	break;
	}

	if (!ret && devset1 != data->mfr_devset1) {
	ret = i2c_smbus_write_word_data(client, MAX20730_MFR_DEVSET1,
	devset1);
	if (!ret) {
	data->mfr_devset1 = devset1;
	pmbus_clear_cache(client);
	}
	}
	mutex_unlock(&data->lock);
	return ret;
	}

	static const struct pmbus_driver_info max20730_info[] = {
	[max20730] = {
	.pages = 1,
	.read_word_data = max20730_read_word_data,
	.write_word_data = max20730_write_word_data,

	/* Source : Maxim AN6042 */
	.format[PSC_TEMPERATURE] = direct,
	.m[PSC_TEMPERATURE] = 21,
	.b[PSC_TEMPERATURE] = 5887,
	.R[PSC_TEMPERATURE] = -1,

	.format[PSC_VOLTAGE_IN] = direct,
	.m[PSC_VOLTAGE_IN] = 3609,
	.b[PSC_VOLTAGE_IN] = 0,
	.R[PSC_VOLTAGE_IN] = -2,

	/*
	* Values in the datasheet are adjusted for temperature and
	* for the relationship between Vin and Vout.
	* Unfortunately, the data sheet suggests that Vout measurement
	* may be scaled with a resistor array. This is indeed the case
	* at least on the evaulation boards. As a result, any in-driver
	* adjustments would either be wrong or require elaborate means
	* to configure the scaling. Instead of doing that, just report
	* raw values and let userspace handle adjustments.
	*/
	.format[PSC_CURRENT_OUT] = direct,
	.m[PSC_CURRENT_OUT] = 153,
	.b[PSC_CURRENT_OUT] = 4976,
	.R[PSC_CURRENT_OUT] = -1,

	.format[PSC_VOLTAGE_OUT] = linear,

	.func[0] = PMBUS_HAVE_VIN \|
	PMBUS_HAVE_VOUT \| PMBUS_HAVE_STATUS_VOUT \|
	PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT \|
	PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP,
	},
	[max20734] = {
	.pages = 1,
	.read_word_data = max20730_read_word_data,
	.write_word_data = max20730_write_word_data,

	/* Source : Maxim AN6209 */
	.format[PSC_TEMPERATURE] = direct,
	.m[PSC_TEMPERATURE] = 21,
	.b[PSC_TEMPERATURE] = 5887,
	.R[PSC_TEMPERATURE] = -1,

	.format[PSC_VOLTAGE_IN] = direct,
	.m[PSC_VOLTAGE_IN] = 3592,
	.b[PSC_VOLTAGE_IN] = 0,
	.R[PSC_VOLTAGE_IN] = -2,

	.format[PSC_CURRENT_OUT] = direct,
	.m[PSC_CURRENT_OUT] = 111,
	.b[PSC_CURRENT_OUT] = 3461,
	.R[PSC_CURRENT_OUT] = -1,

	.format[PSC_VOLTAGE_OUT] = linear,

	.func[0] = PMBUS_HAVE_VIN \|
	PMBUS_HAVE_VOUT \| PMBUS_HAVE_STATUS_VOUT \|
	PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT \|
	PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP,
	},
	[max20743] = {
	.pages = 1,
	.read_word_data = max20730_read_word_data,
	.write_word_data = max20730_write_word_data,

	/* Source : Maxim AN6042 */
	.format[PSC_TEMPERATURE] = direct,
	.m[PSC_TEMPERATURE] = 21,
	.b[PSC_TEMPERATURE] = 5887,
	.R[PSC_TEMPERATURE] = -1,

	.format[PSC_VOLTAGE_IN] = direct,
	.m[PSC_VOLTAGE_IN] = 3597,
	.b[PSC_VOLTAGE_IN] = 0,
	.R[PSC_VOLTAGE_IN] = -2,

	.format[PSC_CURRENT_OUT] = direct,
	.m[PSC_CURRENT_OUT] = 95,
	.b[PSC_CURRENT_OUT] = 5014,
	.R[PSC_CURRENT_OUT] = -1,

	.format[PSC_VOLTAGE_OUT] = linear,

	.func[0] = PMBUS_HAVE_VIN \|
	PMBUS_HAVE_VOUT \| PMBUS_HAVE_STATUS_VOUT \|
	PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT \|
	PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP,
	},
	};

	static int max20730_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
	struct max20730_data *data;
	enum chips chip_id;
	int ret;

	if (!i2c_check_functionality(client->adapter,
	I2C_FUNC_SMBUS_READ_BYTE_DATA \|
	I2C_FUNC_SMBUS_READ_WORD_DATA \|
	I2C_FUNC_SMBUS_BLOCK_DATA))
	return -ENODEV;

	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
	if (ret < 0) {
	dev_err(&client->dev, "Failed to read Manufacturer ID\n");
	return ret;
	}
	if (ret != 5 \|\| strncmp(buf, "MAXIM", 5)) {
	buf[ret] = '\0';
	dev_err(dev, "Unsupported Manufacturer ID '%s'\n", buf);
	return -ENODEV;
	}

	/*
	* The chips support reading PMBUS_MFR_MODEL. On both MAX20730
	* and MAX20734, reading it returns M20743. Presumably that is
	* the reason why the command is not documented. Unfortunately,
	* that means that there is no reliable means to detect the chip.
	* However, we can at least detect the chip series. Compare
	* the returned value against 'M20743' and bail out if there is
	* a mismatch. If that doesn't work for all chips, we may have
	* to remove this check.
	*/
	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
	if (ret < 0) {
	dev_err(dev, "Failed to read Manufacturer Model\n");
	return ret;
	}
	if (ret != 6 \|\| strncmp(buf, "M20743", 6)) {
	buf[ret] = '\0';
	dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
	return -ENODEV;
	}

	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
	if (ret < 0) {
	dev_err(dev, "Failed to read Manufacturer Revision\n");
	return ret;
	}
	if (ret != 1 \|\| buf[0] != 'F') {
	buf[ret] = '\0';
	dev_err(dev, "Unsupported Manufacturer Revision '%s'\n", buf);
	return -ENODEV;
	}

	if (client->dev.of_node)
	chip_id = (enum chips)of_device_get_match_data(dev);
	else
	chip_id = id->driver_data;

	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;
	data->id = chip_id;
	mutex_init(&data->lock);
	memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info));

	ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
	if (ret < 0)
	return ret;
	data->mfr_devset1 = ret;

	return pmbus_do_probe(client, id, &data->info);
	}

	static const struct i2c_device_id max20730_id[] = {
	{ "max20730", max20730 },
	{ "max20734", max20734 },
	{ "max20743", max20743 },
	{ },
	};

	MODULE_DEVICE_TABLE(i2c, max20730_id);

	static const struct of_device_id max20730_of_match[] = {
	{ .compatible = "maxim,max20730", .data = (void *)max20730 },
	{ .compatible = "maxim,max20734", .data = (void *)max20734 },
	{ .compatible = "maxim,max20743", .data = (void *)max20743 },
	{ },
	};

	MODULE_DEVICE_TABLE(of, max20730_of_match);

	static struct i2c_driver max20730_driver = {
	.driver = {
	.name = "max20730",
	.of_match_table = max20730_of_match,
	},
	.probe = max20730_probe,
	.remove = pmbus_do_remove,
	.id_table = max20730_id,
	};

	module_i2c_driver(max20730_driver);

	MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
	MODULE_DESCRIPTION("PMBus driver for Maxim MAX20730 / MAX20734 / MAX20743");
	MODULE_LICENSE("GPL");