drivers/hwmon/lm92.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * lm92 - Hardware monitoring driver
  * Copyright (C) 2005-2008  Jean Delvare <jdelvare@suse.de>
  *
  * Based on the lm90 driver, with some ideas taken from the lm_sensors
  * lm92 driver as well.
  *
  * The LM92 is a sensor chip made by National Semiconductor. It reports
  * its own temperature with a 0.0625 deg resolution and a 0.33 deg
  * accuracy. Complete datasheet can be obtained from National's website
  * at:
  *   http://www.national.com/pf/LM/LM92.html
  *
  * This driver also supports the MAX6635 sensor chip made by Maxim.
  * This chip is compatible with the LM92, but has a lesser accuracy
  * (1.0 deg). Complete datasheet can be obtained from Maxim's website
  * at:
  *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
  *
  * Since the LM92 was the first chipset supported by this driver, most
  * comments will refer to this chipset, but are actually general and
  * concern all supported chipsets, unless mentioned otherwise.
  *
  * Support could easily be added for the National Semiconductor LM76
  * and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
  * with the LM92.
  */

 #include <linux/err.h>
 #include <linux/hwmon.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>

 /*
  * The LM92 and MAX6635 have 2 two-state pins for address selection,
  * resulting in 4 possible addresses.
  */
 static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
 						I2C_CLIENT_END };
 /* The LM92 registers */
 #define LM92_REG_CONFIG			0x01 /* 8-bit, RW */
 #define LM92_REG_TEMP			0x00 /* 16-bit, RO */
 #define LM92_REG_TEMP_HYST		0x02 /* 16-bit, RW */
 #define LM92_REG_TEMP_CRIT		0x03 /* 16-bit, RW */
 #define LM92_REG_TEMP_LOW		0x04 /* 16-bit, RW */
 #define LM92_REG_TEMP_HIGH		0x05 /* 16-bit, RW */
 #define LM92_REG_MAN_ID			0x07 /* 16-bit, RO, LM92 only */

 /*
  * The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
  * left-justified in 16-bit registers. No rounding is done, with such
  * a resolution it's just not worth it. Note that the MAX6635 doesn't
  * make use of the 4 lower bits for limits (i.e. effective resolution
  * for limits is 1 degree Celsius).
  */
 static inline int TEMP_FROM_REG(s16 reg)
 {
 	return reg / 8 * 625 / 10;
 }

 static inline s16 TEMP_TO_REG(long val, int resolution)
 {
 	val = clamp_val(val, -60000, 160000);
 	return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);
 }

 /* Alarm flags are stored in the 3 LSB of the temperature register */
 static inline u8 ALARMS_FROM_REG(s16 reg)
 {
 	return reg & 0x0007;
 }

 /* Client data (each client gets its own) */
 struct lm92_data {
 	struct regmap *regmap;
 	struct mutex update_lock;
 	int resolution;
 };

 static int lm92_temp_read(struct lm92_data *data, u32 attr, int channel, long *val)
 {
 	int reg = -1, hyst_reg = -1, alarm_bit = 0;
 	struct regmap *regmap = data->regmap;
 	u32 temp;
 	int ret;

 	switch (attr) {
 	case hwmon_temp_input:
 		reg = LM92_REG_TEMP;
 		break;
 	case hwmon_temp_min:
 		reg = LM92_REG_TEMP_LOW;
 		break;
 	case hwmon_temp_max:
 		reg = LM92_REG_TEMP_HIGH;
 		break;
 	case hwmon_temp_crit:
 		reg = LM92_REG_TEMP_CRIT;
 		break;
 	case hwmon_temp_min_hyst:
 		hyst_reg = LM92_REG_TEMP_LOW;
 		break;
 	case hwmon_temp_max_hyst:
 		hyst_reg = LM92_REG_TEMP_HIGH;
 		break;
 	case hwmon_temp_crit_hyst:
 		hyst_reg = LM92_REG_TEMP_CRIT;
 		break;
 	case hwmon_temp_min_alarm:
 		alarm_bit = 0;
 		break;
 	case hwmon_temp_max_alarm:
 		alarm_bit = 1;
 		break;
 	case hwmon_temp_crit_alarm:
 		alarm_bit = 2;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 	if (reg >= 0) {
 		ret = regmap_read(regmap, reg, &temp);
 		if (ret < 0)
 			return ret;
 		*val = TEMP_FROM_REG(temp);
 	} else if (hyst_reg >= 0) {
 		u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };
 		u16 regvals[2];

 		ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
 		if (ret)
 			return ret;
 		if (attr == hwmon_temp_min_hyst)
 			*val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);
 		else
 			*val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);
 	} else {
 		ret = regmap_read(regmap, LM92_REG_TEMP, &temp);
 		if (ret)
 			return ret;
 		*val = !!(temp & BIT(alarm_bit));
 	}
 	return 0;
 }

 static int lm92_chip_read(struct lm92_data *data, u32 attr, long *val)
 {
 	u32 temp;
 	int ret;

 	switch (attr) {
 	case hwmon_chip_alarms:
 		ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);
 		if (ret)
 			return ret;
 		*val = ALARMS_FROM_REG(temp);
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 	return 0;
 }

 static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
 		     int channel, long *val)
 {
 	struct lm92_data *data = dev_get_drvdata(dev);

 	switch (type) {
 	case hwmon_chip:
 		return lm92_chip_read(data, attr, val);
 	case hwmon_temp:
 		return lm92_temp_read(data, attr, channel, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)
 {
 	struct regmap *regmap = data->regmap;
 	int reg, err;
 	u32 temp;

 	switch (attr) {
 	case hwmon_temp_min:
 		reg = LM92_REG_TEMP_LOW;
 		break;
 	case hwmon_temp_max:
 		reg = LM92_REG_TEMP_HIGH;
 		break;
 	case hwmon_temp_crit:
 		reg = LM92_REG_TEMP_CRIT;
 		break;
 	case hwmon_temp_crit_hyst:
 		val = clamp_val(val, -120000, 220000);
 		mutex_lock(&data->update_lock);
 		err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);
 		if (err)
 			goto unlock;
 		val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);
 		err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);
 unlock:
 		mutex_unlock(&data->update_lock);
 		return err;
 	default:
 		return -EOPNOTSUPP;
 	}
 	return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));
 }

 static int lm92_write(struct device *dev, enum hwmon_sensor_types type,
 		      u32 attr, int channel, long val)
 {
 	struct lm92_data *data = dev_get_drvdata(dev);

 	switch (type) {
 	case hwmon_temp:
 		return lm92_temp_write(data, attr, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,
 			       u32 attr, int channel)
 {
 	switch (type) {
 	case hwmon_chip:
 		switch (attr) {
 		case hwmon_chip_alarms:
 			return 0444;
 		default:
 			break;
 		}
 		break;
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_min:
 		case hwmon_temp_max:
 		case hwmon_temp_crit:
 		case hwmon_temp_crit_hyst:
 			return 0644;
 		case hwmon_temp_input:
 		case hwmon_temp_min_hyst:
 		case hwmon_temp_max_hyst:
 		case hwmon_temp_min_alarm:
 		case hwmon_temp_max_alarm:
 		case hwmon_temp_crit_alarm:
 			return 0444;
 		default:
 			break;
 		}
 		break;
 	default:
 		break;
 	}
 	return 0;
 }

 static const struct hwmon_channel_info * const lm92_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT |
 			   HWMON_T_MIN | HWMON_T_MIN_HYST |
 			   HWMON_T_MAX | HWMON_T_MAX_HYST |
 			   HWMON_T_CRIT | HWMON_T_CRIT_HYST |
 			   HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
 			   HWMON_T_CRIT_ALARM),
 	NULL
 };

 static const struct hwmon_ops lm92_hwmon_ops = {
 	.is_visible = lm92_is_visible,
 	.read = lm92_read,
 	.write = lm92_write,
 };

 static const struct hwmon_chip_info lm92_chip_info = {
 	.ops = &lm92_hwmon_ops,
 	.info = lm92_info,
 };

 /*
  * Detection and registration
  */

 static int lm92_init_client(struct regmap *regmap)
 {
 	return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);
 }

 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int lm92_detect(struct i2c_client *new_client,
 		       struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = new_client->adapter;
 	u8 config_addr = LM92_REG_CONFIG;
 	u8 man_id_addr = LM92_REG_MAN_ID;
 	int i, regval;

 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
 					    | I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;

 	/*
 	 * Register values repeat with multiples of 8.
 	 * Read twice to improve detection accuracy.
 	 */
 	for (i = 0; i < 2; i++) {
 		regval = i2c_smbus_read_word_data(new_client, man_id_addr);
 		if (regval != 0x0180)
 			return -ENODEV;
 		regval = i2c_smbus_read_byte_data(new_client, config_addr);
 		if (regval < 0 || (regval & 0xe0))
 			return -ENODEV;
 		config_addr += 8;
 		man_id_addr += 8;
 	}

 	strscpy(info->type, "lm92", I2C_NAME_SIZE);

 	return 0;
 }

 /* regmap */

 static int lm92_reg_read(void *context, unsigned int reg, unsigned int *val)
 {
 	int ret;

 	if (reg == LM92_REG_CONFIG)
 		ret = i2c_smbus_read_byte_data(context, reg);
 	else
 		ret = i2c_smbus_read_word_swapped(context, reg);
 	if (ret < 0)
 		return ret;

 	*val = ret;
 	return 0;
 }

 static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)
 {
 	if (reg == LM92_REG_CONFIG)
 		return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);

 	return i2c_smbus_write_word_swapped(context, reg, val);
 }

 static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)
 {
 	return reg == LM92_REG_TEMP;
 }

 static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)
 {
 	return reg >= LM92_REG_CONFIG;
 }

 static const struct regmap_config lm92_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 16,
 	.max_register = LM92_REG_TEMP_HIGH,
 	.cache_type = REGCACHE_MAPLE,
 	.volatile_reg = lm92_regmap_is_volatile,
 	.writeable_reg = lm92_regmap_is_writeable,
 };

 static const struct regmap_bus lm92_regmap_bus = {
 	.reg_write = lm92_reg_write,
 	.reg_read = lm92_reg_read,
 };

 static int lm92_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct lm92_data *data;
 	struct regmap *regmap;
 	int err;

 	regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,
 				  &lm92_regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);

 	data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->regmap = regmap;
 	data->resolution = (unsigned long)i2c_get_match_data(client);
 	mutex_init(&data->update_lock);

 	/* Initialize the chipset */
 	err = lm92_init_client(regmap);
 	if (err)
 		return err;

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
 							 &lm92_chip_info, NULL);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 /*
  * Module and driver stuff
  */

 /* .driver_data is limit register resolution */
 static const struct i2c_device_id lm92_id[] = {
 	{ "lm92", 13 },
 	{ "max6635", 9 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, lm92_id);

 static struct i2c_driver lm92_driver = {
 	.class		= I2C_CLASS_HWMON,
 	.driver = {
 		.name	= "lm92",
 	},
 	.probe		= lm92_probe,
 	.id_table	= lm92_id,
 	.detect		= lm92_detect,
 	.address_list	= normal_i2c,
 };

 module_i2c_driver(lm92_driver);

 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 MODULE_DESCRIPTION("LM92/MAX6635 driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* lm92 - Hardware monitoring driver
	* Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
	*
	* Based on the lm90 driver, with some ideas taken from the lm_sensors
	* lm92 driver as well.
	*
	* The LM92 is a sensor chip made by National Semiconductor. It reports
	* its own temperature with a 0.0625 deg resolution and a 0.33 deg
	* accuracy. Complete datasheet can be obtained from National's website
	* at:
	* http://www.national.com/pf/LM/LM92.html
	*
	* This driver also supports the MAX6635 sensor chip made by Maxim.
	* This chip is compatible with the LM92, but has a lesser accuracy
	* (1.0 deg). Complete datasheet can be obtained from Maxim's website
	* at:
	* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
	*
	* Since the LM92 was the first chipset supported by this driver, most
	* comments will refer to this chipset, but are actually general and
	* concern all supported chipsets, unless mentioned otherwise.
	*
	* Support could easily be added for the National Semiconductor LM76
	* and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
	* with the LM92.
	*/

	#include <linux/err.h>
	#include <linux/hwmon.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/regmap.h>
	#include <linux/slab.h>

	/*
	* The LM92 and MAX6635 have 2 two-state pins for address selection,
	* resulting in 4 possible addresses.
	*/
	static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
	I2C_CLIENT_END };
	/* The LM92 registers */
	#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
	#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
	#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
	#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
	#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
	#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
	#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */

	/*
	* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
	* left-justified in 16-bit registers. No rounding is done, with such
	* a resolution it's just not worth it. Note that the MAX6635 doesn't
	* make use of the 4 lower bits for limits (i.e. effective resolution
	* for limits is 1 degree Celsius).
	*/
	static inline int TEMP_FROM_REG(s16 reg)
	{
	return reg / 8 * 625 / 10;
	}

	static inline s16 TEMP_TO_REG(long val, int resolution)
	{
	val = clamp_val(val, -60000, 160000);
	return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);
	}

	/* Alarm flags are stored in the 3 LSB of the temperature register */
	static inline u8 ALARMS_FROM_REG(s16 reg)
	{
	return reg & 0x0007;
	}

	/* Client data (each client gets its own) */
	struct lm92_data {
	struct regmap *regmap;
	struct mutex update_lock;
	int resolution;
	};

	static int lm92_temp_read(struct lm92_data data, u32 attr, int channel, long val)
	{
	int reg = -1, hyst_reg = -1, alarm_bit = 0;
	struct regmap *regmap = data->regmap;
	u32 temp;
	int ret;

	switch (attr) {
	case hwmon_temp_input:
	reg = LM92_REG_TEMP;
	break;
	case hwmon_temp_min:
	reg = LM92_REG_TEMP_LOW;
	break;
	case hwmon_temp_max:
	reg = LM92_REG_TEMP_HIGH;
	break;
	case hwmon_temp_crit:
	reg = LM92_REG_TEMP_CRIT;
	break;
	case hwmon_temp_min_hyst:
	hyst_reg = LM92_REG_TEMP_LOW;
	break;
	case hwmon_temp_max_hyst:
	hyst_reg = LM92_REG_TEMP_HIGH;
	break;
	case hwmon_temp_crit_hyst:
	hyst_reg = LM92_REG_TEMP_CRIT;
	break;
	case hwmon_temp_min_alarm:
	alarm_bit = 0;
	break;
	case hwmon_temp_max_alarm:
	alarm_bit = 1;
	break;
	case hwmon_temp_crit_alarm:
	alarm_bit = 2;
	break;
	default:
	return -EOPNOTSUPP;
	}
	if (reg >= 0) {
	ret = regmap_read(regmap, reg, &temp);
	if (ret < 0)
	return ret;
	*val = TEMP_FROM_REG(temp);
	} else if (hyst_reg >= 0) {
	u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };
	u16 regvals[2];

	ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
	if (ret)
	return ret;
	if (attr == hwmon_temp_min_hyst)
	*val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);
	else
	*val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);
	} else {
	ret = regmap_read(regmap, LM92_REG_TEMP, &temp);
	if (ret)
	return ret;
	*val = !!(temp & BIT(alarm_bit));
	}
	return 0;
	}

	static int lm92_chip_read(struct lm92_data data, u32 attr, long val)
	{
	u32 temp;
	int ret;

	switch (attr) {
	case hwmon_chip_alarms:
	ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);
	if (ret)
	return ret;
	*val = ALARMS_FROM_REG(temp);
	break;
	default:
	return -EOPNOTSUPP;
	}
	return 0;
	}

	static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
	int channel, long *val)
	{
	struct lm92_data *data = dev_get_drvdata(dev);

	switch (type) {
	case hwmon_chip:
	return lm92_chip_read(data, attr, val);
	case hwmon_temp:
	return lm92_temp_read(data, attr, channel, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)
	{
	struct regmap *regmap = data->regmap;
	int reg, err;
	u32 temp;

	switch (attr) {
	case hwmon_temp_min:
	reg = LM92_REG_TEMP_LOW;
	break;
	case hwmon_temp_max:
	reg = LM92_REG_TEMP_HIGH;
	break;
	case hwmon_temp_crit:
	reg = LM92_REG_TEMP_CRIT;
	break;
	case hwmon_temp_crit_hyst:
	val = clamp_val(val, -120000, 220000);
	mutex_lock(&data->update_lock);
	err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);
	if (err)
	goto unlock;
	val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);
	err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);
	unlock:
	mutex_unlock(&data->update_lock);
	return err;
	default:
	return -EOPNOTSUPP;
	}
	return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));
	}

	static int lm92_write(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long val)
	{
	struct lm92_data *data = dev_get_drvdata(dev);

	switch (type) {
	case hwmon_temp:
	return lm92_temp_write(data, attr, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	switch (type) {
	case hwmon_chip:
	switch (attr) {
	case hwmon_chip_alarms:
	return 0444;
	default:
	break;
	}
	break;
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_min:
	case hwmon_temp_max:
	case hwmon_temp_crit:
	case hwmon_temp_crit_hyst:
	return 0644;
	case hwmon_temp_input:
	case hwmon_temp_min_hyst:
	case hwmon_temp_max_hyst:
	case hwmon_temp_min_alarm:
	case hwmon_temp_max_alarm:
	case hwmon_temp_crit_alarm:
	return 0444;
	default:
	break;
	}
	break;
	default:
	break;
	}
	return 0;
	}

	static const struct hwmon_channel_info * const lm92_info[] = {
	HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
	HWMON_CHANNEL_INFO(temp,
	HWMON_T_INPUT \|
	HWMON_T_MIN \| HWMON_T_MIN_HYST \|
	HWMON_T_MAX \| HWMON_T_MAX_HYST \|
	HWMON_T_CRIT \| HWMON_T_CRIT_HYST \|
	HWMON_T_MIN_ALARM \| HWMON_T_MAX_ALARM \|
	HWMON_T_CRIT_ALARM),
	NULL
	};

	static const struct hwmon_ops lm92_hwmon_ops = {
	.is_visible = lm92_is_visible,
	.read = lm92_read,
	.write = lm92_write,
	};

	static const struct hwmon_chip_info lm92_chip_info = {
	.ops = &lm92_hwmon_ops,
	.info = lm92_info,
	};

	/*
	* Detection and registration
	*/

	static int lm92_init_client(struct regmap *regmap)
	{
	return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);
	}

	/* Return 0 if detection is successful, -ENODEV otherwise */
	static int lm92_detect(struct i2c_client *new_client,
	struct i2c_board_info *info)
	{
	struct i2c_adapter *adapter = new_client->adapter;
	u8 config_addr = LM92_REG_CONFIG;
	u8 man_id_addr = LM92_REG_MAN_ID;
	int i, regval;

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
	\| I2C_FUNC_SMBUS_WORD_DATA))
	return -ENODEV;

	/*
	* Register values repeat with multiples of 8.
	* Read twice to improve detection accuracy.
	*/
	for (i = 0; i < 2; i++) {
	regval = i2c_smbus_read_word_data(new_client, man_id_addr);
	if (regval != 0x0180)
	return -ENODEV;
	regval = i2c_smbus_read_byte_data(new_client, config_addr);
	if (regval < 0 \|\| (regval & 0xe0))
	return -ENODEV;
	config_addr += 8;
	man_id_addr += 8;
	}

	strscpy(info->type, "lm92", I2C_NAME_SIZE);

	return 0;
	}

	/* regmap */

	static int lm92_reg_read(void context, unsigned int reg, unsigned int val)
	{
	int ret;

	if (reg == LM92_REG_CONFIG)
	ret = i2c_smbus_read_byte_data(context, reg);
	else
	ret = i2c_smbus_read_word_swapped(context, reg);
	if (ret < 0)
	return ret;

	*val = ret;
	return 0;
	}

	static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)
	{
	if (reg == LM92_REG_CONFIG)
	return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);

	return i2c_smbus_write_word_swapped(context, reg, val);
	}

	static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)
	{
	return reg == LM92_REG_TEMP;
	}

	static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)
	{
	return reg >= LM92_REG_CONFIG;
	}

	static const struct regmap_config lm92_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = LM92_REG_TEMP_HIGH,
	.cache_type = REGCACHE_MAPLE,
	.volatile_reg = lm92_regmap_is_volatile,
	.writeable_reg = lm92_regmap_is_writeable,
	};

	static const struct regmap_bus lm92_regmap_bus = {
	.reg_write = lm92_reg_write,
	.reg_read = lm92_reg_read,
	};

	static int lm92_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct lm92_data *data;
	struct regmap *regmap;
	int err;

	regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,
	&lm92_regmap_config);
	if (IS_ERR(regmap))
	return PTR_ERR(regmap);

	data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->regmap = regmap;
	data->resolution = (unsigned long)i2c_get_match_data(client);
	mutex_init(&data->update_lock);

	/* Initialize the chipset */
	err = lm92_init_client(regmap);
	if (err)
	return err;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
	&lm92_chip_info, NULL);
	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	/*
	* Module and driver stuff
	*/

	/* .driver_data is limit register resolution */
	static const struct i2c_device_id lm92_id[] = {
	{ "lm92", 13 },
	{ "max6635", 9 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, lm92_id);

	static struct i2c_driver lm92_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "lm92",
	},
	.probe = lm92_probe,
	.id_table = lm92_id,
	.detect = lm92_detect,
	.address_list = normal_i2c,
	};

	module_i2c_driver(lm92_driver);

	MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
	MODULE_DESCRIPTION("LM92/MAX6635 driver");
	MODULE_LICENSE("GPL");