drivers/hwmon/pmbus/max16601.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Hardware monitoring driver for Maxim MAX16508 and MAX16601.
  *
  * Implementation notes:
  *
  * This chip series supports two rails, VCORE and VSA. Telemetry information
  * for the two rails is reported in two subsequent I2C addresses. The driver
  * instantiates a dummy I2C client at the second I2C address to report
  * information for the VSA rail in a single instance of the driver.
  * Telemetry for the VSA rail is reported to the PMBus core in PMBus page 2.
  *
  * The chip reports input current using two separate methods. The input current
  * reported with the standard READ_IIN command is derived from the output
  * current. The first method is reported to the PMBus core with PMBus page 0,
  * the second method is reported with PMBus page 1.
  *
  * The chip supports reading per-phase temperatures and per-phase input/output
  * currents for VCORE. Telemetry is reported in vendor specific registers.
  * The driver translates the vendor specific register values to PMBus standard
  * register values and reports per-phase information in PMBus page 0.
  *
  * Copyright 2019, 2020 Google LLC.
  */

 #include <linux/bits.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>

 #include "pmbus.h"

 enum chips { max16508, max16601 };

 #define REG_DEFAULT_NUM_POP	0xc4
 #define REG_SETPT_DVID		0xd1
 #define  DAC_10MV_MODE		BIT(4)
 #define REG_IOUT_AVG_PK		0xee
 #define REG_IIN_SENSOR		0xf1
 #define REG_TOTAL_INPUT_POWER	0xf2
 #define REG_PHASE_ID		0xf3
 #define  CORE_RAIL_INDICATOR	BIT(7)
 #define REG_PHASE_REPORTING	0xf4

 #define MAX16601_NUM_PHASES	8

 struct max16601_data {
 	enum chips id;
 	struct pmbus_driver_info info;
 	struct i2c_client *vsa;
 	int iout_avg_pkg;
 };

 #define to_max16601_data(x) container_of(x, struct max16601_data, info)

 static int max16601_read_byte(struct i2c_client *client, int page, int reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 	struct max16601_data *data = to_max16601_data(info);

 	if (page > 0) {
 		if (page == 2)	/* VSA */
 			return i2c_smbus_read_byte_data(data->vsa, reg);
 		return -EOPNOTSUPP;
 	}
 	return -ENODATA;
 }

 static int max16601_read_word(struct i2c_client *client, int page, int phase,
 			      int reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 	struct max16601_data *data = to_max16601_data(info);
 	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
 	int ret;

 	switch (page) {
 	case 0:		/* VCORE */
 		if (phase == 0xff)
 			return -ENODATA;
 		switch (reg) {
 		case PMBUS_READ_IIN:
 		case PMBUS_READ_IOUT:
 		case PMBUS_READ_TEMPERATURE_1:
 			ret = i2c_smbus_write_byte_data(client, REG_PHASE_ID,
 							phase);
 			if (ret)
 				return ret;
 			ret = i2c_smbus_read_block_data(client,
 							REG_PHASE_REPORTING,
 							buf);
 			if (ret < 0)
 				return ret;
 			if (ret < 6)
 				return -EIO;
 			switch (reg) {
 			case PMBUS_READ_TEMPERATURE_1:
 				return buf[1] << 8 | buf[0];
 			case PMBUS_READ_IOUT:
 				return buf[3] << 8 | buf[2];
 			case PMBUS_READ_IIN:
 				return buf[5] << 8 | buf[4];
 			default:
 				break;
 			}
 		}
 		return -EOPNOTSUPP;
 	case 1:		/* VCORE, read IIN/PIN from sensor element */
 		switch (reg) {
 		case PMBUS_READ_IIN:
 			return i2c_smbus_read_word_data(client, REG_IIN_SENSOR);
 		case PMBUS_READ_PIN:
 			return i2c_smbus_read_word_data(client,
 							REG_TOTAL_INPUT_POWER);
 		default:
 			break;
 		}
 		return -EOPNOTSUPP;
 	case 2:		/* VSA */
 		switch (reg) {
 		case PMBUS_VIRT_READ_IOUT_MAX:
 			ret = i2c_smbus_read_word_data(data->vsa,
 						       REG_IOUT_AVG_PK);
 			if (ret < 0)
 				return ret;
 			if (sign_extend32(ret, 10) >
 			    sign_extend32(data->iout_avg_pkg, 10))
 				data->iout_avg_pkg = ret;
 			return data->iout_avg_pkg;
 		case PMBUS_VIRT_RESET_IOUT_HISTORY:
 			return 0;
 		case PMBUS_IOUT_OC_FAULT_LIMIT:
 		case PMBUS_IOUT_OC_WARN_LIMIT:
 		case PMBUS_OT_FAULT_LIMIT:
 		case PMBUS_OT_WARN_LIMIT:
 		case PMBUS_READ_IIN:
 		case PMBUS_READ_IOUT:
 		case PMBUS_READ_TEMPERATURE_1:
 		case PMBUS_STATUS_WORD:
 			return i2c_smbus_read_word_data(data->vsa, reg);
 		default:
 			return -EOPNOTSUPP;
 		}
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int max16601_write_byte(struct i2c_client *client, int page, u8 reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 	struct max16601_data *data = to_max16601_data(info);

 	if (page == 2) {
 		if (reg == PMBUS_CLEAR_FAULTS)
 			return i2c_smbus_write_byte(data->vsa, reg);
 		return -EOPNOTSUPP;
 	}
 	return -ENODATA;
 }

 static int max16601_write_word(struct i2c_client *client, int page, int reg,
 			       u16 value)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
 	struct max16601_data *data = to_max16601_data(info);

 	switch (page) {
 	case 0:		/* VCORE */
 		return -ENODATA;
 	case 1:		/* VCORE IIN/PIN from sensor element */
 	default:
 		return -EOPNOTSUPP;
 	case 2:		/* VSA */
 		switch (reg) {
 		case PMBUS_VIRT_RESET_IOUT_HISTORY:
 			data->iout_avg_pkg = 0xfc00;
 			return 0;
 		case PMBUS_IOUT_OC_FAULT_LIMIT:
 		case PMBUS_IOUT_OC_WARN_LIMIT:
 		case PMBUS_OT_FAULT_LIMIT:
 		case PMBUS_OT_WARN_LIMIT:
 			return i2c_smbus_write_word_data(data->vsa, reg, value);
 		default:
 			return -EOPNOTSUPP;
 		}
 	}
 }

 static int max16601_identify(struct i2c_client *client,
 			     struct pmbus_driver_info *info)
 {
 	struct max16601_data *data = to_max16601_data(info);
 	int reg;

 	reg = i2c_smbus_read_byte_data(client, REG_SETPT_DVID);
 	if (reg < 0)
 		return reg;
 	if (reg & DAC_10MV_MODE)
 		info->vrm_version[0] = vr13;
 	else
 		info->vrm_version[0] = vr12;

 	if (data->id != max16601)
 		return 0;

 	reg = i2c_smbus_read_byte_data(client, REG_DEFAULT_NUM_POP);
 	if (reg < 0)
 		return reg;

 	/*
 	 * If REG_DEFAULT_NUM_POP returns 0, we don't know how many phases
 	 * are populated. Stick with the default in that case.
 	 */
 	reg &= 0x0f;
 	if (reg && reg <= MAX16601_NUM_PHASES)
 		info->phases[0] = reg;

 	return 0;
 }

 static struct pmbus_driver_info max16601_info = {
 	.pages = 3,
 	.format[PSC_VOLTAGE_IN] = linear,
 	.format[PSC_VOLTAGE_OUT] = vid,
 	.format[PSC_CURRENT_IN] = linear,
 	.format[PSC_CURRENT_OUT] = linear,
 	.format[PSC_TEMPERATURE] = linear,
 	.format[PSC_POWER] = linear,
 	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN | PMBUS_HAVE_PIN |
 		PMBUS_HAVE_STATUS_INPUT |
 		PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
 		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
 		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
 		PMBUS_HAVE_POUT | PMBUS_PAGE_VIRTUAL | PMBUS_PHASE_VIRTUAL,
 	.func[1] = PMBUS_HAVE_IIN | PMBUS_HAVE_PIN | PMBUS_PAGE_VIRTUAL,
 	.func[2] = PMBUS_HAVE_IIN | PMBUS_HAVE_STATUS_INPUT |
 		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
 		PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP | PMBUS_PAGE_VIRTUAL,
 	.phases[0] = MAX16601_NUM_PHASES,
 	.pfunc[0] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 	.pfunc[1] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
 	.pfunc[2] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 	.pfunc[3] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
 	.pfunc[4] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 	.pfunc[5] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
 	.pfunc[6] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_TEMP,
 	.pfunc[7] = PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT,
 	.identify = max16601_identify,
 	.read_byte_data = max16601_read_byte,
 	.read_word_data = max16601_read_word,
 	.write_byte = max16601_write_byte,
 	.write_word_data = max16601_write_word,
 };

 static void max16601_remove(void *_data)
 {
 	struct max16601_data *data = _data;

 	i2c_unregister_device(data->vsa);
 }

 static const struct i2c_device_id max16601_id[] = {
 	{"max16508", max16508},
 	{"max16601", max16601},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, max16601_id);

 static int max16601_get_id(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
 	enum chips id;
 	int ret;

 	ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
 	if (ret < 0 || ret < 11)
 		return -ENODEV;

 	/*
 	 * PMBUS_IC_DEVICE_ID is expected to return "MAX16601y.xx"
 	 * or "MAX16500y.xx".
 	 */
 	if (!strncmp(buf, "MAX16500", 8)) {
 		id = max16508;
 	} else if (!strncmp(buf, "MAX16601", 8)) {
 		id = max16601;
 	} else {
 		buf[ret] = '\0';
 		dev_err(dev, "Unsupported chip '%s'\n", buf);
 		return -ENODEV;
 	}
 	return id;
 }

 static int max16601_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	const struct i2c_device_id *id;
 	struct max16601_data *data;
 	int ret, chip_id;

 	if (!i2c_check_functionality(client->adapter,
 				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
 				     I2C_FUNC_SMBUS_READ_BLOCK_DATA))
 		return -ENODEV;

 	chip_id = max16601_get_id(client);
 	if (chip_id < 0)
 		return chip_id;

 	id = i2c_match_id(max16601_id, client);
 	if (chip_id != id->driver_data)
 		dev_warn(&client->dev,
 			 "Device mismatch: Configured %s (%d), detected %d\n",
 			 id->name, (int) id->driver_data, chip_id);

 	ret = i2c_smbus_read_byte_data(client, REG_PHASE_ID);
 	if (ret < 0)
 		return ret;
 	if (!(ret & CORE_RAIL_INDICATOR)) {
 		dev_err(dev,
 			"Driver must be instantiated on CORE rail I2C address\n");
 		return -ENODEV;
 	}

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

 	data->id = chip_id;
 	data->iout_avg_pkg = 0xfc00;
 	data->vsa = i2c_new_dummy_device(client->adapter, client->addr + 1);
 	if (IS_ERR(data->vsa)) {
 		dev_err(dev, "Failed to register VSA client\n");
 		return PTR_ERR(data->vsa);
 	}
 	ret = devm_add_action_or_reset(dev, max16601_remove, data);
 	if (ret)
 		return ret;

 	data->info = max16601_info;

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

 static struct i2c_driver max16601_driver = {
 	.driver = {
 		   .name = "max16601",
 		   },
 	.probe_new = max16601_probe,
 	.id_table = max16601_id,
 };

 module_i2c_driver(max16601_driver);

 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 MODULE_DESCRIPTION("PMBus driver for Maxim MAX16601");
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(PMBUS);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Hardware monitoring driver for Maxim MAX16508 and MAX16601.
	*
	* Implementation notes:
	*
	* This chip series supports two rails, VCORE and VSA. Telemetry information
	* for the two rails is reported in two subsequent I2C addresses. The driver
	* instantiates a dummy I2C client at the second I2C address to report
	* information for the VSA rail in a single instance of the driver.
	* Telemetry for the VSA rail is reported to the PMBus core in PMBus page 2.
	*
	* The chip reports input current using two separate methods. The input current
	* reported with the standard READ_IIN command is derived from the output
	* current. The first method is reported to the PMBus core with PMBus page 0,
	* the second method is reported with PMBus page 1.
	*
	* The chip supports reading per-phase temperatures and per-phase input/output
	* currents for VCORE. Telemetry is reported in vendor specific registers.
	* The driver translates the vendor specific register values to PMBus standard
	* register values and reports per-phase information in PMBus page 0.
	*
	* Copyright 2019, 2020 Google LLC.
	*/

	#include <linux/bits.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>

	#include "pmbus.h"

	enum chips { max16508, max16601 };

	#define REG_DEFAULT_NUM_POP 0xc4
	#define REG_SETPT_DVID 0xd1
	#define DAC_10MV_MODE BIT(4)
	#define REG_IOUT_AVG_PK 0xee
	#define REG_IIN_SENSOR 0xf1
	#define REG_TOTAL_INPUT_POWER 0xf2
	#define REG_PHASE_ID 0xf3
	#define CORE_RAIL_INDICATOR BIT(7)
	#define REG_PHASE_REPORTING 0xf4

	#define MAX16601_NUM_PHASES 8

	struct max16601_data {
	enum chips id;
	struct pmbus_driver_info info;
	struct i2c_client *vsa;
	int iout_avg_pkg;
	};

	#define to_max16601_data(x) container_of(x, struct max16601_data, info)

	static int max16601_read_byte(struct i2c_client *client, int page, int reg)
	{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct max16601_data *data = to_max16601_data(info);

	if (page > 0) {
	if (page == 2) /* VSA */
	return i2c_smbus_read_byte_data(data->vsa, reg);
	return -EOPNOTSUPP;
	}
	return -ENODATA;
	}

	static int max16601_read_word(struct i2c_client *client, int page, int phase,
	int reg)
	{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct max16601_data *data = to_max16601_data(info);
	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
	int ret;

	switch (page) {
	case 0: /* VCORE */
	if (phase == 0xff)
	return -ENODATA;
	switch (reg) {
	case PMBUS_READ_IIN:
	case PMBUS_READ_IOUT:
	case PMBUS_READ_TEMPERATURE_1:
	ret = i2c_smbus_write_byte_data(client, REG_PHASE_ID,
	phase);
	if (ret)
	return ret;
	ret = i2c_smbus_read_block_data(client,
	REG_PHASE_REPORTING,
	buf);
	if (ret < 0)
	return ret;
	if (ret < 6)
	return -EIO;
	switch (reg) {
	case PMBUS_READ_TEMPERATURE_1:
	return buf[1] << 8 \| buf[0];
	case PMBUS_READ_IOUT:
	return buf[3] << 8 \| buf[2];
	case PMBUS_READ_IIN:
	return buf[5] << 8 \| buf[4];
	default:
	break;
	}
	}
	return -EOPNOTSUPP;
	case 1: /* VCORE, read IIN/PIN from sensor element */
	switch (reg) {
	case PMBUS_READ_IIN:
	return i2c_smbus_read_word_data(client, REG_IIN_SENSOR);
	case PMBUS_READ_PIN:
	return i2c_smbus_read_word_data(client,
	REG_TOTAL_INPUT_POWER);
	default:
	break;
	}
	return -EOPNOTSUPP;
	case 2: /* VSA */
	switch (reg) {
	case PMBUS_VIRT_READ_IOUT_MAX:
	ret = i2c_smbus_read_word_data(data->vsa,
	REG_IOUT_AVG_PK);
	if (ret < 0)
	return ret;
	if (sign_extend32(ret, 10) >
	sign_extend32(data->iout_avg_pkg, 10))
	data->iout_avg_pkg = ret;
	return data->iout_avg_pkg;
	case PMBUS_VIRT_RESET_IOUT_HISTORY:
	return 0;
	case PMBUS_IOUT_OC_FAULT_LIMIT:
	case PMBUS_IOUT_OC_WARN_LIMIT:
	case PMBUS_OT_FAULT_LIMIT:
	case PMBUS_OT_WARN_LIMIT:
	case PMBUS_READ_IIN:
	case PMBUS_READ_IOUT:
	case PMBUS_READ_TEMPERATURE_1:
	case PMBUS_STATUS_WORD:
	return i2c_smbus_read_word_data(data->vsa, reg);
	default:
	return -EOPNOTSUPP;
	}
	default:
	return -EOPNOTSUPP;
	}
	}

	static int max16601_write_byte(struct i2c_client *client, int page, u8 reg)
	{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct max16601_data *data = to_max16601_data(info);

	if (page == 2) {
	if (reg == PMBUS_CLEAR_FAULTS)
	return i2c_smbus_write_byte(data->vsa, reg);
	return -EOPNOTSUPP;
	}
	return -ENODATA;
	}

	static int max16601_write_word(struct i2c_client *client, int page, int reg,
	u16 value)
	{
	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
	struct max16601_data *data = to_max16601_data(info);

	switch (page) {
	case 0: /* VCORE */
	return -ENODATA;
	case 1: /* VCORE IIN/PIN from sensor element */
	default:
	return -EOPNOTSUPP;
	case 2: /* VSA */
	switch (reg) {
	case PMBUS_VIRT_RESET_IOUT_HISTORY:
	data->iout_avg_pkg = 0xfc00;
	return 0;
	case PMBUS_IOUT_OC_FAULT_LIMIT:
	case PMBUS_IOUT_OC_WARN_LIMIT:
	case PMBUS_OT_FAULT_LIMIT:
	case PMBUS_OT_WARN_LIMIT:
	return i2c_smbus_write_word_data(data->vsa, reg, value);
	default:
	return -EOPNOTSUPP;
	}
	}
	}

	static int max16601_identify(struct i2c_client *client,
	struct pmbus_driver_info *info)
	{
	struct max16601_data *data = to_max16601_data(info);
	int reg;

	reg = i2c_smbus_read_byte_data(client, REG_SETPT_DVID);
	if (reg < 0)
	return reg;
	if (reg & DAC_10MV_MODE)
	info->vrm_version[0] = vr13;
	else
	info->vrm_version[0] = vr12;

	if (data->id != max16601)
	return 0;

	reg = i2c_smbus_read_byte_data(client, REG_DEFAULT_NUM_POP);
	if (reg < 0)
	return reg;

	/*
	* If REG_DEFAULT_NUM_POP returns 0, we don't know how many phases
	* are populated. Stick with the default in that case.
	*/
	reg &= 0x0f;
	if (reg && reg <= MAX16601_NUM_PHASES)
	info->phases[0] = reg;

	return 0;
	}

	static struct pmbus_driver_info max16601_info = {
	.pages = 3,
	.format[PSC_VOLTAGE_IN] = linear,
	.format[PSC_VOLTAGE_OUT] = vid,
	.format[PSC_CURRENT_IN] = linear,
	.format[PSC_CURRENT_OUT] = linear,
	.format[PSC_TEMPERATURE] = linear,
	.format[PSC_POWER] = linear,
	.func[0] = PMBUS_HAVE_VIN \| PMBUS_HAVE_IIN \| PMBUS_HAVE_PIN \|
	PMBUS_HAVE_STATUS_INPUT \|
	PMBUS_HAVE_VOUT \| PMBUS_HAVE_STATUS_VOUT \|
	PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT \|
	PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP \|
	PMBUS_HAVE_POUT \| PMBUS_PAGE_VIRTUAL \| PMBUS_PHASE_VIRTUAL,
	.func[1] = PMBUS_HAVE_IIN \| PMBUS_HAVE_PIN \| PMBUS_PAGE_VIRTUAL,
	.func[2] = PMBUS_HAVE_IIN \| PMBUS_HAVE_STATUS_INPUT \|
	PMBUS_HAVE_IOUT \| PMBUS_HAVE_STATUS_IOUT \|
	PMBUS_HAVE_TEMP \| PMBUS_HAVE_STATUS_TEMP \| PMBUS_PAGE_VIRTUAL,
	.phases[0] = MAX16601_NUM_PHASES,
	.pfunc[0] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT \| PMBUS_HAVE_TEMP,
	.pfunc[1] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT,
	.pfunc[2] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT \| PMBUS_HAVE_TEMP,
	.pfunc[3] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT,
	.pfunc[4] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT \| PMBUS_HAVE_TEMP,
	.pfunc[5] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT,
	.pfunc[6] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT \| PMBUS_HAVE_TEMP,
	.pfunc[7] = PMBUS_HAVE_IIN \| PMBUS_HAVE_IOUT,
	.identify = max16601_identify,
	.read_byte_data = max16601_read_byte,
	.read_word_data = max16601_read_word,
	.write_byte = max16601_write_byte,
	.write_word_data = max16601_write_word,
	};

	static void max16601_remove(void *_data)
	{
	struct max16601_data *data = _data;

	i2c_unregister_device(data->vsa);
	}

	static const struct i2c_device_id max16601_id[] = {
	{"max16508", max16508},
	{"max16601", max16601},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, max16601_id);

	static int max16601_get_id(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
	enum chips id;
	int ret;

	ret = i2c_smbus_read_block_data(client, PMBUS_IC_DEVICE_ID, buf);
	if (ret < 0 \|\| ret < 11)
	return -ENODEV;

	/*
	* PMBUS_IC_DEVICE_ID is expected to return "MAX16601y.xx"
	* or "MAX16500y.xx".
	*/
	if (!strncmp(buf, "MAX16500", 8)) {
	id = max16508;
	} else if (!strncmp(buf, "MAX16601", 8)) {
	id = max16601;
	} else {
	buf[ret] = '\0';
	dev_err(dev, "Unsupported chip '%s'\n", buf);
	return -ENODEV;
	}
	return id;
	}

	static int max16601_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	const struct i2c_device_id *id;
	struct max16601_data *data;
	int ret, chip_id;

	if (!i2c_check_functionality(client->adapter,
	I2C_FUNC_SMBUS_READ_BYTE_DATA \|
	I2C_FUNC_SMBUS_READ_BLOCK_DATA))
	return -ENODEV;

	chip_id = max16601_get_id(client);
	if (chip_id < 0)
	return chip_id;

	id = i2c_match_id(max16601_id, client);
	if (chip_id != id->driver_data)
	dev_warn(&client->dev,
	"Device mismatch: Configured %s (%d), detected %d\n",
	id->name, (int) id->driver_data, chip_id);

	ret = i2c_smbus_read_byte_data(client, REG_PHASE_ID);
	if (ret < 0)
	return ret;
	if (!(ret & CORE_RAIL_INDICATOR)) {
	dev_err(dev,
	"Driver must be instantiated on CORE rail I2C address\n");
	return -ENODEV;
	}

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

	data->id = chip_id;
	data->iout_avg_pkg = 0xfc00;
	data->vsa = i2c_new_dummy_device(client->adapter, client->addr + 1);
	if (IS_ERR(data->vsa)) {
	dev_err(dev, "Failed to register VSA client\n");
	return PTR_ERR(data->vsa);
	}
	ret = devm_add_action_or_reset(dev, max16601_remove, data);
	if (ret)
	return ret;

	data->info = max16601_info;

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

	static struct i2c_driver max16601_driver = {
	.driver = {
	.name = "max16601",
	},
	.probe_new = max16601_probe,
	.id_table = max16601_id,
	};

	module_i2c_driver(max16601_driver);

	MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
	MODULE_DESCRIPTION("PMBus driver for Maxim MAX16601");
	MODULE_LICENSE("GPL v2");
	MODULE_IMPORT_NS(PMBUS);