drivers/hwmon/max6621.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Hardware monitoring driver for Maxim MAX6621
  *
  * Copyright (c) 2017 Mellanox Technologies. All rights reserved.
  * Copyright (c) 2017 Vadim Pasternak <vadimp@mellanox.com>
  */

 #include <linux/bitops.h>
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/regmap.h>

 #define MAX6621_DRV_NAME		"max6621"
 #define MAX6621_TEMP_INPUT_REG_NUM	9
 #define MAX6621_TEMP_INPUT_MIN		-127000
 #define MAX6621_TEMP_INPUT_MAX		128000
 #define MAX6621_TEMP_ALERT_CHAN_SHIFT	1

 #define MAX6621_TEMP_S0D0_REG		0x00
 #define MAX6621_TEMP_S0D1_REG		0x01
 #define MAX6621_TEMP_S1D0_REG		0x02
 #define MAX6621_TEMP_S1D1_REG		0x03
 #define MAX6621_TEMP_S2D0_REG		0x04
 #define MAX6621_TEMP_S2D1_REG		0x05
 #define MAX6621_TEMP_S3D0_REG		0x06
 #define MAX6621_TEMP_S3D1_REG		0x07
 #define MAX6621_TEMP_MAX_REG		0x08
 #define MAX6621_TEMP_MAX_ADDR_REG	0x0a
 #define MAX6621_TEMP_ALERT_CAUSE_REG	0x0b
 #define MAX6621_CONFIG0_REG		0x0c
 #define MAX6621_CONFIG1_REG		0x0d
 #define MAX6621_CONFIG2_REG		0x0e
 #define MAX6621_CONFIG3_REG		0x0f
 #define MAX6621_TEMP_S0_ALERT_REG	0x10
 #define MAX6621_TEMP_S1_ALERT_REG	0x11
 #define MAX6621_TEMP_S2_ALERT_REG	0x12
 #define MAX6621_TEMP_S3_ALERT_REG	0x13
 #define MAX6621_CLEAR_ALERT_REG		0x15
 #define MAX6621_REG_MAX			(MAX6621_CLEAR_ALERT_REG + 1)
 #define MAX6621_REG_TEMP_SHIFT		0x06

 #define MAX6621_ENABLE_TEMP_ALERTS_BIT	4
 #define MAX6621_ENABLE_I2C_CRC_BIT	5
 #define MAX6621_ENABLE_ALTERNATE_DATA	6
 #define MAX6621_ENABLE_LOCKUP_TO	7
 #define MAX6621_ENABLE_S0D0_BIT		8
 #define MAX6621_ENABLE_S3D1_BIT		15
 #define MAX6621_ENABLE_TEMP_ALL		GENMASK(MAX6621_ENABLE_S3D1_BIT, \
 						MAX6621_ENABLE_S0D0_BIT)
 #define MAX6621_POLL_DELAY_MASK		0x5
 #define MAX6621_CONFIG0_INIT		(MAX6621_ENABLE_TEMP_ALL | \
 					 BIT(MAX6621_ENABLE_LOCKUP_TO) | \
 					 BIT(MAX6621_ENABLE_I2C_CRC_BIT) | \
 					 MAX6621_POLL_DELAY_MASK)
 #define MAX6621_PECI_BIT_TIME		0x2
 #define MAX6621_PECI_RETRY_NUM		0x3
 #define MAX6621_CONFIG1_INIT		((MAX6621_PECI_BIT_TIME << 8) | \
 					 MAX6621_PECI_RETRY_NUM)

 /* Error codes */
 #define MAX6621_TRAN_FAILED	0x8100	/*
 					 * PECI transaction failed for more
 					 * than the configured number of
 					 * consecutive retries.
 					 */
 #define MAX6621_POOL_DIS	0x8101	/*
 					 * Polling disabled for requested
 					 * socket/domain.
 					 */
 #define MAX6621_POOL_UNCOMPLETE	0x8102	/*
 					 * First poll not yet completed for
 					 * requested socket/domain (on
 					 * startup).
 					 */
 #define MAX6621_SD_DIS		0x8103	/*
 					 * Read maximum temperature requested,
 					 * but no sockets/domains enabled or
 					 * all enabled sockets/domains have
 					 * errors; or read maximum temperature
 					 * address requested, but read maximum
 					 * temperature was not called.
 					 */
 #define MAX6621_ALERT_DIS	0x8104	/*
 					 * Get alert socket/domain requested,
 					 * but no alert active.
 					 */
 #define MAX6621_PECI_ERR_MIN	0x8000	/* Intel spec PECI error min value. */
 #define MAX6621_PECI_ERR_MAX	0x80ff	/* Intel spec PECI error max value. */

 static const u32 max6621_temp_regs[] = {
 	MAX6621_TEMP_MAX_REG, MAX6621_TEMP_S0D0_REG, MAX6621_TEMP_S1D0_REG,
 	MAX6621_TEMP_S2D0_REG, MAX6621_TEMP_S3D0_REG, MAX6621_TEMP_S0D1_REG,
 	MAX6621_TEMP_S1D1_REG, MAX6621_TEMP_S2D1_REG, MAX6621_TEMP_S3D1_REG,
 };

 static const char *const max6621_temp_labels[] = {
 	"maximum",
 	"socket0_0",
 	"socket1_0",
 	"socket2_0",
 	"socket3_0",
 	"socket0_1",
 	"socket1_1",
 	"socket2_1",
 	"socket3_1",
 };

 static const int max6621_temp_alert_chan2reg[] = {
 	MAX6621_TEMP_S0_ALERT_REG,
 	MAX6621_TEMP_S1_ALERT_REG,
 	MAX6621_TEMP_S2_ALERT_REG,
 	MAX6621_TEMP_S3_ALERT_REG,
 };

 /**
  * struct max6621_data - private data:
  *
  * @client: I2C client;
  * @regmap: register map handle;
  * @input_chan2reg: mapping from channel to register;
  */
 struct max6621_data {
 	struct i2c_client	*client;
 	struct regmap		*regmap;
 	int			input_chan2reg[MAX6621_TEMP_INPUT_REG_NUM + 1];
 };

 static long max6621_temp_mc2reg(long val)
 {
 	return (val / 1000L) << MAX6621_REG_TEMP_SHIFT;
 }

 static umode_t
 max6621_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
 		   int channel)
 {
 	/* Skip channels which are not physically conncted. */
 	if (((struct max6621_data *)data)->input_chan2reg[channel] < 0)
 		return 0;

 	switch (type) {
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_input:
 		case hwmon_temp_label:
 		case hwmon_temp_crit_alarm:
 			return 0444;
 		case hwmon_temp_offset:
 		case hwmon_temp_crit:
 			return 0644;
 		default:
 			break;
 		}
 		break;
 	default:
 		break;
 	}

 	return 0;
 }

 static int max6621_verify_reg_data(struct device *dev, int regval)
 {
 	if (regval >= MAX6621_PECI_ERR_MIN &&
 	    regval <= MAX6621_PECI_ERR_MAX) {
 		dev_dbg(dev, "PECI error code - err 0x%04x.\n",
 			regval);

 		return -EIO;
 	}

 	switch (regval) {
 	case MAX6621_TRAN_FAILED:
 		dev_dbg(dev, "PECI transaction failed - err 0x%04x.\n",
 			regval);
 		return -EIO;
 	case MAX6621_POOL_DIS:
 		dev_dbg(dev, "Polling disabled - err 0x%04x.\n", regval);
 		return -EOPNOTSUPP;
 	case MAX6621_POOL_UNCOMPLETE:
 		dev_dbg(dev, "First poll not completed on startup - err 0x%04x.\n",
 			regval);
 		return -EIO;
 	case MAX6621_SD_DIS:
 		dev_dbg(dev, "Resource is disabled - err 0x%04x.\n", regval);
 		return -EOPNOTSUPP;
 	case MAX6621_ALERT_DIS:
 		dev_dbg(dev, "No alert active - err 0x%04x.\n", regval);
 		return -EOPNOTSUPP;
 	default:
 		return 0;
 	}
 }

 static int
 max6621_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 	     int channel, long *val)
 {
 	struct max6621_data *data = dev_get_drvdata(dev);
 	u32 regval;
 	int reg;
 	s8 temp;
 	int ret;

 	switch (type) {
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_input:
 			reg = data->input_chan2reg[channel];
 			ret = regmap_read(data->regmap, reg, &regval);
 			if (ret)
 				return ret;

 			ret = max6621_verify_reg_data(dev, regval);
 			if (ret)
 				return ret;

 			/*
 			 * Bit MAX6621_REG_TEMP_SHIFT represents 1 degree step.
 			 * The temperature is given in two's complement and 8
 			 * bits is used for the register conversion.
 			 */
 			temp = (regval >> MAX6621_REG_TEMP_SHIFT);
 			*val = temp * 1000L;

 			break;
 		case hwmon_temp_offset:
 			ret = regmap_read(data->regmap, MAX6621_CONFIG2_REG,
 					  &regval);
 			if (ret)
 				return ret;

 			ret = max6621_verify_reg_data(dev, regval);
 			if (ret)
 				return ret;

 			*val = (regval >> MAX6621_REG_TEMP_SHIFT) *
 			       1000L;

 			break;
 		case hwmon_temp_crit:
 			channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
 			reg = max6621_temp_alert_chan2reg[channel];
 			ret = regmap_read(data->regmap, reg, &regval);
 			if (ret)
 				return ret;

 			ret = max6621_verify_reg_data(dev, regval);
 			if (ret)
 				return ret;

 			*val = regval * 1000L;

 			break;
 		case hwmon_temp_crit_alarm:
 			/*
 			 * Set val to zero to recover the case, when reading
 			 * MAX6621_TEMP_ALERT_CAUSE_REG results in for example
 			 * MAX6621_ALERT_DIS. Reading will return with error,
 			 * but in such case alarm should be returned as 0.
 			 */
 			*val = 0;
 			ret = regmap_read(data->regmap,
 					  MAX6621_TEMP_ALERT_CAUSE_REG,
 					  &regval);
 			if (ret)
 				return ret;

 			ret = max6621_verify_reg_data(dev, regval);
 			if (ret) {
 				/* Do not report error if alert is disabled. */
 				if (regval == MAX6621_ALERT_DIS)
 					return 0;
 				else
 					return ret;
 			}

 			/*
 			 * Clear the alert automatically, using send-byte
 			 * smbus protocol for clearing alert.
 			 */
 			if (regval) {
 				ret = i2c_smbus_write_byte(data->client,
 						MAX6621_CLEAR_ALERT_REG);
 				if (ret)
 					return ret;
 			}

 			*val = !!regval;

 			break;
 		default:
 			return -EOPNOTSUPP;
 		}
 		break;

 	default:
 		return -EOPNOTSUPP;
 	}

 	return 0;
 }

 static int
 max6621_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 	      int channel, long val)
 {
 	struct max6621_data *data = dev_get_drvdata(dev);
 	u32 reg;

 	switch (type) {
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_offset:
 			/* Clamp to allowed range to prevent overflow. */
 			val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
 					MAX6621_TEMP_INPUT_MAX);
 			val = max6621_temp_mc2reg(val);

 			return regmap_write(data->regmap,
 					    MAX6621_CONFIG2_REG, val);
 		case hwmon_temp_crit:
 			channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
 			reg = max6621_temp_alert_chan2reg[channel];
 			/* Clamp to allowed range to prevent overflow. */
 			val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
 					MAX6621_TEMP_INPUT_MAX);
 			val = val / 1000L;

 			return regmap_write(data->regmap, reg, val);
 		default:
 			return -EOPNOTSUPP;
 		}
 		break;

 	default:
 		return -EOPNOTSUPP;
 	}

 	return -EOPNOTSUPP;
 }

 static int
 max6621_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 		    int channel, const char **str)
 {
 	switch (type) {
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_label:
 			*str = max6621_temp_labels[channel];
 			return 0;
 		default:
 			return -EOPNOTSUPP;
 		}
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	return -EOPNOTSUPP;
 }

 static bool max6621_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case MAX6621_CONFIG0_REG:
 	case MAX6621_CONFIG1_REG:
 	case MAX6621_CONFIG2_REG:
 	case MAX6621_CONFIG3_REG:
 	case MAX6621_TEMP_S0_ALERT_REG:
 	case MAX6621_TEMP_S1_ALERT_REG:
 	case MAX6621_TEMP_S2_ALERT_REG:
 	case MAX6621_TEMP_S3_ALERT_REG:
 	case MAX6621_TEMP_ALERT_CAUSE_REG:
 		return true;
 	}
 	return false;
 }

 static bool max6621_readable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case MAX6621_TEMP_S0D0_REG:
 	case MAX6621_TEMP_S0D1_REG:
 	case MAX6621_TEMP_S1D0_REG:
 	case MAX6621_TEMP_S1D1_REG:
 	case MAX6621_TEMP_S2D0_REG:
 	case MAX6621_TEMP_S2D1_REG:
 	case MAX6621_TEMP_S3D0_REG:
 	case MAX6621_TEMP_S3D1_REG:
 	case MAX6621_TEMP_MAX_REG:
 	case MAX6621_TEMP_MAX_ADDR_REG:
 	case MAX6621_CONFIG0_REG:
 	case MAX6621_CONFIG1_REG:
 	case MAX6621_CONFIG2_REG:
 	case MAX6621_CONFIG3_REG:
 	case MAX6621_TEMP_S0_ALERT_REG:
 	case MAX6621_TEMP_S1_ALERT_REG:
 	case MAX6621_TEMP_S2_ALERT_REG:
 	case MAX6621_TEMP_S3_ALERT_REG:
 		return true;
 	}
 	return false;
 }

 static bool max6621_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case MAX6621_TEMP_S0D0_REG:
 	case MAX6621_TEMP_S0D1_REG:
 	case MAX6621_TEMP_S1D0_REG:
 	case MAX6621_TEMP_S1D1_REG:
 	case MAX6621_TEMP_S2D0_REG:
 	case MAX6621_TEMP_S2D1_REG:
 	case MAX6621_TEMP_S3D0_REG:
 	case MAX6621_TEMP_S3D1_REG:
 	case MAX6621_TEMP_MAX_REG:
 	case MAX6621_TEMP_S0_ALERT_REG:
 	case MAX6621_TEMP_S1_ALERT_REG:
 	case MAX6621_TEMP_S2_ALERT_REG:
 	case MAX6621_TEMP_S3_ALERT_REG:
 	case MAX6621_TEMP_ALERT_CAUSE_REG:
 		return true;
 	}
 	return false;
 }

 static const struct reg_default max6621_regmap_default[] = {
 	{ MAX6621_CONFIG0_REG, MAX6621_CONFIG0_INIT },
 	{ MAX6621_CONFIG1_REG, MAX6621_CONFIG1_INIT },
 };

 static const struct regmap_config max6621_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 16,
 	.max_register = MAX6621_REG_MAX,
 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
 	.cache_type = REGCACHE_FLAT,
 	.writeable_reg = max6621_writeable_reg,
 	.readable_reg = max6621_readable_reg,
 	.volatile_reg = max6621_volatile_reg,
 	.reg_defaults = max6621_regmap_default,
 	.num_reg_defaults = ARRAY_SIZE(max6621_regmap_default),
 };

 static const struct hwmon_channel_info * const max6621_info[] = {
 	HWMON_CHANNEL_INFO(chip,
 			   HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_LABEL | HWMON_T_OFFSET,
 			   HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_ALARM | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_LABEL),
 	NULL
 };

 static const struct hwmon_ops max6621_hwmon_ops = {
 	.read = max6621_read,
 	.write = max6621_write,
 	.read_string = max6621_read_string,
 	.is_visible = max6621_is_visible,
 };

 static const struct hwmon_chip_info max6621_chip_info = {
 	.ops = &max6621_hwmon_ops,
 	.info = max6621_info,
 };

 static int max6621_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct max6621_data *data;
 	struct device *hwmon_dev;
 	int i;
 	int ret;

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

 	data->regmap = devm_regmap_init_i2c(client, &max6621_regmap_config);
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);

 	i2c_set_clientdata(client, data);
 	data->client = client;

 	/* Set CONFIG0 register masking temperature alerts and PEC. */
 	ret = regmap_write(data->regmap, MAX6621_CONFIG0_REG,
 			   MAX6621_CONFIG0_INIT);
 	if (ret)
 		return ret;

 	/* Set CONFIG1 register for PEC access retry number. */
 	ret = regmap_write(data->regmap, MAX6621_CONFIG1_REG,
 			   MAX6621_CONFIG1_INIT);
 	if (ret)
 		return ret;

 	/* Sync registers with hardware. */
 	regcache_mark_dirty(data->regmap);
 	ret = regcache_sync(data->regmap);
 	if (ret)
 		return ret;

 	/* Verify which temperature input registers are enabled. */
 	for (i = 0; i < MAX6621_TEMP_INPUT_REG_NUM; i++) {
 		ret = i2c_smbus_read_word_data(client, max6621_temp_regs[i]);
 		if (ret < 0)
 			return ret;
 		ret = max6621_verify_reg_data(dev, ret);
 		if (ret) {
 			data->input_chan2reg[i] = -1;
 			continue;
 		}

 		data->input_chan2reg[i] = max6621_temp_regs[i];
 	}

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 							 data,
 							 &max6621_chip_info,
 							 NULL);

 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 static const struct i2c_device_id max6621_id[] = {
 	{ MAX6621_DRV_NAME },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, max6621_id);

 static const struct of_device_id __maybe_unused max6621_of_match[] = {
 	{ .compatible = "maxim,max6621" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, max6621_of_match);

 static struct i2c_driver max6621_driver = {
 	.driver = {
 		.name = MAX6621_DRV_NAME,
 		.of_match_table = of_match_ptr(max6621_of_match),
 	},
 	.probe		= max6621_probe,
 	.id_table	= max6621_id,
 };

 module_i2c_driver(max6621_driver);

 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
 MODULE_DESCRIPTION("Driver for Maxim MAX6621");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Hardware monitoring driver for Maxim MAX6621
	*
	* Copyright (c) 2017 Mellanox Technologies. All rights reserved.
	* Copyright (c) 2017 Vadim Pasternak <vadimp@mellanox.com>
	*/

	#include <linux/bitops.h>
	#include <linux/hwmon.h>
	#include <linux/hwmon-sysfs.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/regmap.h>

	#define MAX6621_DRV_NAME "max6621"
	#define MAX6621_TEMP_INPUT_REG_NUM 9
	#define MAX6621_TEMP_INPUT_MIN -127000
	#define MAX6621_TEMP_INPUT_MAX 128000
	#define MAX6621_TEMP_ALERT_CHAN_SHIFT 1

	#define MAX6621_TEMP_S0D0_REG 0x00
	#define MAX6621_TEMP_S0D1_REG 0x01
	#define MAX6621_TEMP_S1D0_REG 0x02
	#define MAX6621_TEMP_S1D1_REG 0x03
	#define MAX6621_TEMP_S2D0_REG 0x04
	#define MAX6621_TEMP_S2D1_REG 0x05
	#define MAX6621_TEMP_S3D0_REG 0x06
	#define MAX6621_TEMP_S3D1_REG 0x07
	#define MAX6621_TEMP_MAX_REG 0x08
	#define MAX6621_TEMP_MAX_ADDR_REG 0x0a
	#define MAX6621_TEMP_ALERT_CAUSE_REG 0x0b
	#define MAX6621_CONFIG0_REG 0x0c
	#define MAX6621_CONFIG1_REG 0x0d
	#define MAX6621_CONFIG2_REG 0x0e
	#define MAX6621_CONFIG3_REG 0x0f
	#define MAX6621_TEMP_S0_ALERT_REG 0x10
	#define MAX6621_TEMP_S1_ALERT_REG 0x11
	#define MAX6621_TEMP_S2_ALERT_REG 0x12
	#define MAX6621_TEMP_S3_ALERT_REG 0x13
	#define MAX6621_CLEAR_ALERT_REG 0x15
	#define MAX6621_REG_MAX (MAX6621_CLEAR_ALERT_REG + 1)
	#define MAX6621_REG_TEMP_SHIFT 0x06

	#define MAX6621_ENABLE_TEMP_ALERTS_BIT 4
	#define MAX6621_ENABLE_I2C_CRC_BIT 5
	#define MAX6621_ENABLE_ALTERNATE_DATA 6
	#define MAX6621_ENABLE_LOCKUP_TO 7
	#define MAX6621_ENABLE_S0D0_BIT 8
	#define MAX6621_ENABLE_S3D1_BIT 15
	#define MAX6621_ENABLE_TEMP_ALL GENMASK(MAX6621_ENABLE_S3D1_BIT, \
	MAX6621_ENABLE_S0D0_BIT)
	#define MAX6621_POLL_DELAY_MASK 0x5
	#define MAX6621_CONFIG0_INIT (MAX6621_ENABLE_TEMP_ALL \| \
	BIT(MAX6621_ENABLE_LOCKUP_TO) \| \
	BIT(MAX6621_ENABLE_I2C_CRC_BIT) \| \
	MAX6621_POLL_DELAY_MASK)
	#define MAX6621_PECI_BIT_TIME 0x2
	#define MAX6621_PECI_RETRY_NUM 0x3
	#define MAX6621_CONFIG1_INIT ((MAX6621_PECI_BIT_TIME << 8) \| \
	MAX6621_PECI_RETRY_NUM)

	/* Error codes */
	#define MAX6621_TRAN_FAILED 0x8100 /*
	* PECI transaction failed for more
	* than the configured number of
	* consecutive retries.
	*/
	#define MAX6621_POOL_DIS 0x8101 /*
	* Polling disabled for requested
	* socket/domain.
	*/
	#define MAX6621_POOL_UNCOMPLETE 0x8102 /*
	* First poll not yet completed for
	* requested socket/domain (on
	* startup).
	*/
	#define MAX6621_SD_DIS 0x8103 /*
	* Read maximum temperature requested,
	* but no sockets/domains enabled or
	* all enabled sockets/domains have
	* errors; or read maximum temperature
	* address requested, but read maximum
	* temperature was not called.
	*/
	#define MAX6621_ALERT_DIS 0x8104 /*
	* Get alert socket/domain requested,
	* but no alert active.
	*/
	#define MAX6621_PECI_ERR_MIN 0x8000 /* Intel spec PECI error min value. */
	#define MAX6621_PECI_ERR_MAX 0x80ff /* Intel spec PECI error max value. */

	static const u32 max6621_temp_regs[] = {
	MAX6621_TEMP_MAX_REG, MAX6621_TEMP_S0D0_REG, MAX6621_TEMP_S1D0_REG,
	MAX6621_TEMP_S2D0_REG, MAX6621_TEMP_S3D0_REG, MAX6621_TEMP_S0D1_REG,
	MAX6621_TEMP_S1D1_REG, MAX6621_TEMP_S2D1_REG, MAX6621_TEMP_S3D1_REG,
	};

	static const char *const max6621_temp_labels[] = {
	"maximum",
	"socket0_0",
	"socket1_0",
	"socket2_0",
	"socket3_0",
	"socket0_1",
	"socket1_1",
	"socket2_1",
	"socket3_1",
	};

	static const int max6621_temp_alert_chan2reg[] = {
	MAX6621_TEMP_S0_ALERT_REG,
	MAX6621_TEMP_S1_ALERT_REG,
	MAX6621_TEMP_S2_ALERT_REG,
	MAX6621_TEMP_S3_ALERT_REG,
	};

	/**
	* struct max6621_data - private data:
	*
	* @client: I2C client;
	* @regmap: register map handle;
	* @input_chan2reg: mapping from channel to register;
	*/
	struct max6621_data {
	struct i2c_client *client;
	struct regmap *regmap;
	int input_chan2reg[MAX6621_TEMP_INPUT_REG_NUM + 1];
	};

	static long max6621_temp_mc2reg(long val)
	{
	return (val / 1000L) << MAX6621_REG_TEMP_SHIFT;
	}

	static umode_t
	max6621_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
	int channel)
	{
	/* Skip channels which are not physically conncted. */
	if (((struct max6621_data *)data)->input_chan2reg[channel] < 0)
	return 0;

	switch (type) {
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_input:
	case hwmon_temp_label:
	case hwmon_temp_crit_alarm:
	return 0444;
	case hwmon_temp_offset:
	case hwmon_temp_crit:
	return 0644;
	default:
	break;
	}
	break;
	default:
	break;
	}

	return 0;
	}

	static int max6621_verify_reg_data(struct device *dev, int regval)
	{
	if (regval >= MAX6621_PECI_ERR_MIN &&
	regval <= MAX6621_PECI_ERR_MAX) {
	dev_dbg(dev, "PECI error code - err 0x%04x.\n",
	regval);

	return -EIO;
	}

	switch (regval) {
	case MAX6621_TRAN_FAILED:
	dev_dbg(dev, "PECI transaction failed - err 0x%04x.\n",
	regval);
	return -EIO;
	case MAX6621_POOL_DIS:
	dev_dbg(dev, "Polling disabled - err 0x%04x.\n", regval);
	return -EOPNOTSUPP;
	case MAX6621_POOL_UNCOMPLETE:
	dev_dbg(dev, "First poll not completed on startup - err 0x%04x.\n",
	regval);
	return -EIO;
	case MAX6621_SD_DIS:
	dev_dbg(dev, "Resource is disabled - err 0x%04x.\n", regval);
	return -EOPNOTSUPP;
	case MAX6621_ALERT_DIS:
	dev_dbg(dev, "No alert active - err 0x%04x.\n", regval);
	return -EOPNOTSUPP;
	default:
	return 0;
	}
	}

	static int
	max6621_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	int channel, long *val)
	{
	struct max6621_data *data = dev_get_drvdata(dev);
	u32 regval;
	int reg;
	s8 temp;
	int ret;

	switch (type) {
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_input:
	reg = data->input_chan2reg[channel];
	ret = regmap_read(data->regmap, reg, &regval);
	if (ret)
	return ret;

	ret = max6621_verify_reg_data(dev, regval);
	if (ret)
	return ret;

	/*
	* Bit MAX6621_REG_TEMP_SHIFT represents 1 degree step.
	* The temperature is given in two's complement and 8
	* bits is used for the register conversion.
	*/
	temp = (regval >> MAX6621_REG_TEMP_SHIFT);
	val = temp 1000L;

	break;
	case hwmon_temp_offset:
	ret = regmap_read(data->regmap, MAX6621_CONFIG2_REG,
	&regval);
	if (ret)
	return ret;

	ret = max6621_verify_reg_data(dev, regval);
	if (ret)
	return ret;

	val = (regval >> MAX6621_REG_TEMP_SHIFT)
	1000L;

	break;
	case hwmon_temp_crit:
	channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
	reg = max6621_temp_alert_chan2reg[channel];
	ret = regmap_read(data->regmap, reg, &regval);
	if (ret)
	return ret;

	ret = max6621_verify_reg_data(dev, regval);
	if (ret)
	return ret;

	val = regval 1000L;

	break;
	case hwmon_temp_crit_alarm:
	/*
	* Set val to zero to recover the case, when reading
	* MAX6621_TEMP_ALERT_CAUSE_REG results in for example
	* MAX6621_ALERT_DIS. Reading will return with error,
	* but in such case alarm should be returned as 0.
	*/
	*val = 0;
	ret = regmap_read(data->regmap,
	MAX6621_TEMP_ALERT_CAUSE_REG,
	&regval);
	if (ret)
	return ret;

	ret = max6621_verify_reg_data(dev, regval);
	if (ret) {
	/* Do not report error if alert is disabled. */
	if (regval == MAX6621_ALERT_DIS)
	return 0;
	else
	return ret;
	}

	/*
	* Clear the alert automatically, using send-byte
	* smbus protocol for clearing alert.
	*/
	if (regval) {
	ret = i2c_smbus_write_byte(data->client,
	MAX6621_CLEAR_ALERT_REG);
	if (ret)
	return ret;
	}

	*val = !!regval;

	break;
	default:
	return -EOPNOTSUPP;
	}
	break;

	default:
	return -EOPNOTSUPP;
	}

	return 0;
	}

	static int
	max6621_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	int channel, long val)
	{
	struct max6621_data *data = dev_get_drvdata(dev);
	u32 reg;

	switch (type) {
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_offset:
	/* Clamp to allowed range to prevent overflow. */
	val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
	MAX6621_TEMP_INPUT_MAX);
	val = max6621_temp_mc2reg(val);

	return regmap_write(data->regmap,
	MAX6621_CONFIG2_REG, val);
	case hwmon_temp_crit:
	channel -= MAX6621_TEMP_ALERT_CHAN_SHIFT;
	reg = max6621_temp_alert_chan2reg[channel];
	/* Clamp to allowed range to prevent overflow. */
	val = clamp_val(val, MAX6621_TEMP_INPUT_MIN,
	MAX6621_TEMP_INPUT_MAX);
	val = val / 1000L;

	return regmap_write(data->regmap, reg, val);
	default:
	return -EOPNOTSUPP;
	}
	break;

	default:
	return -EOPNOTSUPP;
	}

	return -EOPNOTSUPP;
	}

	static int
	max6621_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	int channel, const char **str)
	{
	switch (type) {
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_label:
	*str = max6621_temp_labels[channel];
	return 0;
	default:
	return -EOPNOTSUPP;
	}
	break;
	default:
	return -EOPNOTSUPP;
	}

	return -EOPNOTSUPP;
	}

	static bool max6621_writeable_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case MAX6621_CONFIG0_REG:
	case MAX6621_CONFIG1_REG:
	case MAX6621_CONFIG2_REG:
	case MAX6621_CONFIG3_REG:
	case MAX6621_TEMP_S0_ALERT_REG:
	case MAX6621_TEMP_S1_ALERT_REG:
	case MAX6621_TEMP_S2_ALERT_REG:
	case MAX6621_TEMP_S3_ALERT_REG:
	case MAX6621_TEMP_ALERT_CAUSE_REG:
	return true;
	}
	return false;
	}

	static bool max6621_readable_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case MAX6621_TEMP_S0D0_REG:
	case MAX6621_TEMP_S0D1_REG:
	case MAX6621_TEMP_S1D0_REG:
	case MAX6621_TEMP_S1D1_REG:
	case MAX6621_TEMP_S2D0_REG:
	case MAX6621_TEMP_S2D1_REG:
	case MAX6621_TEMP_S3D0_REG:
	case MAX6621_TEMP_S3D1_REG:
	case MAX6621_TEMP_MAX_REG:
	case MAX6621_TEMP_MAX_ADDR_REG:
	case MAX6621_CONFIG0_REG:
	case MAX6621_CONFIG1_REG:
	case MAX6621_CONFIG2_REG:
	case MAX6621_CONFIG3_REG:
	case MAX6621_TEMP_S0_ALERT_REG:
	case MAX6621_TEMP_S1_ALERT_REG:
	case MAX6621_TEMP_S2_ALERT_REG:
	case MAX6621_TEMP_S3_ALERT_REG:
	return true;
	}
	return false;
	}

	static bool max6621_volatile_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case MAX6621_TEMP_S0D0_REG:
	case MAX6621_TEMP_S0D1_REG:
	case MAX6621_TEMP_S1D0_REG:
	case MAX6621_TEMP_S1D1_REG:
	case MAX6621_TEMP_S2D0_REG:
	case MAX6621_TEMP_S2D1_REG:
	case MAX6621_TEMP_S3D0_REG:
	case MAX6621_TEMP_S3D1_REG:
	case MAX6621_TEMP_MAX_REG:
	case MAX6621_TEMP_S0_ALERT_REG:
	case MAX6621_TEMP_S1_ALERT_REG:
	case MAX6621_TEMP_S2_ALERT_REG:
	case MAX6621_TEMP_S3_ALERT_REG:
	case MAX6621_TEMP_ALERT_CAUSE_REG:
	return true;
	}
	return false;
	}

	static const struct reg_default max6621_regmap_default[] = {
	{ MAX6621_CONFIG0_REG, MAX6621_CONFIG0_INIT },
	{ MAX6621_CONFIG1_REG, MAX6621_CONFIG1_INIT },
	};

	static const struct regmap_config max6621_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = MAX6621_REG_MAX,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
	.cache_type = REGCACHE_FLAT,
	.writeable_reg = max6621_writeable_reg,
	.readable_reg = max6621_readable_reg,
	.volatile_reg = max6621_volatile_reg,
	.reg_defaults = max6621_regmap_default,
	.num_reg_defaults = ARRAY_SIZE(max6621_regmap_default),
	};

	static const struct hwmon_channel_info * const max6621_info[] = {
	HWMON_CHANNEL_INFO(chip,
	HWMON_C_REGISTER_TZ),
	HWMON_CHANNEL_INFO(temp,
	HWMON_T_INPUT \| HWMON_T_LABEL \| HWMON_T_OFFSET,
	HWMON_T_INPUT \| HWMON_T_CRIT \| HWMON_T_CRIT_ALARM \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_CRIT \| HWMON_T_CRIT_ALARM \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_CRIT \| HWMON_T_CRIT_ALARM \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_CRIT \| HWMON_T_CRIT_ALARM \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_LABEL,
	HWMON_T_INPUT \| HWMON_T_LABEL),
	NULL
	};

	static const struct hwmon_ops max6621_hwmon_ops = {
	.read = max6621_read,
	.write = max6621_write,
	.read_string = max6621_read_string,
	.is_visible = max6621_is_visible,
	};

	static const struct hwmon_chip_info max6621_chip_info = {
	.ops = &max6621_hwmon_ops,
	.info = max6621_info,
	};

	static int max6621_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct max6621_data *data;
	struct device *hwmon_dev;
	int i;
	int ret;

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

	data->regmap = devm_regmap_init_i2c(client, &max6621_regmap_config);
	if (IS_ERR(data->regmap))
	return PTR_ERR(data->regmap);

	i2c_set_clientdata(client, data);
	data->client = client;

	/* Set CONFIG0 register masking temperature alerts and PEC. */
	ret = regmap_write(data->regmap, MAX6621_CONFIG0_REG,
	MAX6621_CONFIG0_INIT);
	if (ret)
	return ret;

	/* Set CONFIG1 register for PEC access retry number. */
	ret = regmap_write(data->regmap, MAX6621_CONFIG1_REG,
	MAX6621_CONFIG1_INIT);
	if (ret)
	return ret;

	/* Sync registers with hardware. */
	regcache_mark_dirty(data->regmap);
	ret = regcache_sync(data->regmap);
	if (ret)
	return ret;

	/* Verify which temperature input registers are enabled. */
	for (i = 0; i < MAX6621_TEMP_INPUT_REG_NUM; i++) {
	ret = i2c_smbus_read_word_data(client, max6621_temp_regs[i]);
	if (ret < 0)
	return ret;
	ret = max6621_verify_reg_data(dev, ret);
	if (ret) {
	data->input_chan2reg[i] = -1;
	continue;
	}

	data->input_chan2reg[i] = max6621_temp_regs[i];
	}

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
	data,
	&max6621_chip_info,
	NULL);

	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	static const struct i2c_device_id max6621_id[] = {
	{ MAX6621_DRV_NAME },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, max6621_id);

	static const struct of_device_id __maybe_unused max6621_of_match[] = {
	{ .compatible = "maxim,max6621" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, max6621_of_match);

	static struct i2c_driver max6621_driver = {
	.driver = {
	.name = MAX6621_DRV_NAME,
	.of_match_table = of_match_ptr(max6621_of_match),
	},
	.probe = max6621_probe,
	.id_table = max6621_id,
	};

	module_i2c_driver(max6621_driver);

	MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
	MODULE_DESCRIPTION("Driver for Maxim MAX6621");
	MODULE_LICENSE("GPL");