drivers/hwmon/lm95245.c - linux - Git at Google

 /*
  * Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
  *
  * The LM95245 is a sensor chip made by TI / National Semiconductor.
  * It reports up to two temperatures (its own plus an external one).
  *
  * This driver is based on lm95241.c
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

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

 static const unsigned short normal_i2c[] = {
 	0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };

 /* LM95245 registers */
 /* general registers */
 #define LM95245_REG_RW_CONFIG1		0x03
 #define LM95245_REG_RW_CONVERS_RATE	0x04
 #define LM95245_REG_W_ONE_SHOT		0x0F

 /* diode configuration */
 #define LM95245_REG_RW_CONFIG2		0xBF
 #define LM95245_REG_RW_REMOTE_OFFH	0x11
 #define LM95245_REG_RW_REMOTE_OFFL	0x12

 /* status registers */
 #define LM95245_REG_R_STATUS1		0x02
 #define LM95245_REG_R_STATUS2		0x33

 /* limit registers */
 #define LM95245_REG_RW_REMOTE_OS_LIMIT		0x07
 #define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT	0x20
 #define LM95245_REG_RW_REMOTE_TCRIT_LIMIT	0x19
 #define LM95245_REG_RW_COMMON_HYSTERESIS	0x21

 /* temperature signed */
 #define LM95245_REG_R_LOCAL_TEMPH_S	0x00
 #define LM95245_REG_R_LOCAL_TEMPL_S	0x30
 #define LM95245_REG_R_REMOTE_TEMPH_S	0x01
 #define LM95245_REG_R_REMOTE_TEMPL_S	0x10
 /* temperature unsigned */
 #define LM95245_REG_R_REMOTE_TEMPH_U	0x31
 #define LM95245_REG_R_REMOTE_TEMPL_U	0x32

 /* id registers */
 #define LM95245_REG_R_MAN_ID		0xFE
 #define LM95245_REG_R_CHIP_ID		0xFF

 /* LM95245 specific bitfields */
 #define CFG_STOP		0x40
 #define CFG_REMOTE_TCRIT_MASK	0x10
 #define CFG_REMOTE_OS_MASK	0x08
 #define CFG_LOCAL_TCRIT_MASK	0x04
 #define CFG_LOCAL_OS_MASK	0x02

 #define CFG2_OS_A0		0x40
 #define CFG2_DIODE_FAULT_OS	0x20
 #define CFG2_DIODE_FAULT_TCRIT	0x10
 #define CFG2_REMOTE_TT		0x08
 #define CFG2_REMOTE_FILTER_DIS	0x00
 #define CFG2_REMOTE_FILTER_EN	0x06

 /* conversation rate in ms */
 #define RATE_CR0063	0x00
 #define RATE_CR0364	0x01
 #define RATE_CR1000	0x02
 #define RATE_CR2500	0x03

 #define STATUS1_ROS		0x10
 #define STATUS1_DIODE_FAULT	0x04
 #define STATUS1_RTCRIT		0x02
 #define STATUS1_LOC		0x01

 #define MANUFACTURER_ID		0x01
 #define LM95235_REVISION	0xB1
 #define LM95245_REVISION	0xB3

 /* Client data (each client gets its own) */
 struct lm95245_data {
 	struct regmap *regmap;
 	struct mutex update_lock;
 	int interval;	/* in msecs */
 };

 /* Conversions */
 static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
 {
 	return val_h * 1000 + val_l * 1000 / 256;
 }

 static int temp_from_reg_signed(u8 val_h, u8 val_l)
 {
 	if (val_h & 0x80)
 		return (val_h - 0x100) * 1000;
 	return temp_from_reg_unsigned(val_h, val_l);
 }

 static int lm95245_read_conversion_rate(struct lm95245_data *data)
 {
 	unsigned int rate;
 	int ret;

 	ret = regmap_read(data->regmap, LM95245_REG_RW_CONVERS_RATE, &rate);
 	if (ret < 0)
 		return ret;

 	switch (rate) {
 	case RATE_CR0063:
 		data->interval = 63;
 		break;
 	case RATE_CR0364:
 		data->interval = 364;
 		break;
 	case RATE_CR1000:
 		data->interval = 1000;
 		break;
 	case RATE_CR2500:
 	default:
 		data->interval = 2500;
 		break;
 	}
 	return 0;
 }

 static int lm95245_set_conversion_rate(struct lm95245_data *data, long interval)
 {
 	int ret, rate;

 	if (interval <= 63) {
 		interval = 63;
 		rate = RATE_CR0063;
 	} else if (interval <= 364) {
 		interval = 364;
 		rate = RATE_CR0364;
 	} else if (interval <= 1000) {
 		interval = 1000;
 		rate = RATE_CR1000;
 	} else {
 		interval = 2500;
 		rate = RATE_CR2500;
 	}

 	ret = regmap_write(data->regmap, LM95245_REG_RW_CONVERS_RATE, rate);
 	if (ret < 0)
 		return ret;

 	data->interval = interval;
 	return 0;
 }

 static int lm95245_read_temp(struct device *dev, u32 attr, int channel,
 			     long *val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	int ret, regl, regh, regvall, regvalh;

 	switch (attr) {
 	case hwmon_temp_input:
 		regl = channel ? LM95245_REG_R_REMOTE_TEMPL_S :
 				 LM95245_REG_R_LOCAL_TEMPL_S;
 		regh = channel ? LM95245_REG_R_REMOTE_TEMPH_S :
 				 LM95245_REG_R_LOCAL_TEMPH_S;
 		ret = regmap_read(regmap, regl, &regvall);
 		if (ret < 0)
 			return ret;
 		ret = regmap_read(regmap, regh, &regvalh);
 		if (ret < 0)
 			return ret;
 		/*
 		 * Local temp is always signed.
 		 * Remote temp has both signed and unsigned data.
 		 * Use signed calculation for remote if signed bit is set
 		 * or if reported temperature is below signed limit.
 		 */
 		if (!channel || (regvalh & 0x80) || regvalh < 0x7f) {
 			*val = temp_from_reg_signed(regvalh, regvall);
 			return 0;
 		}
 		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPL_U,
 				  &regvall);
 		if (ret < 0)
 			return ret;
 		ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPH_U,
 				  &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = temp_from_reg_unsigned(regvalh, regvall);
 		return 0;
 	case hwmon_temp_max:
 		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
 				  &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = regvalh * 1000;
 		return 0;
 	case hwmon_temp_crit:
 		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
 				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
 		ret = regmap_read(regmap, regh, &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = regvalh * 1000;
 		return 0;
 	case hwmon_temp_max_hyst:
 		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
 				  &regvalh);
 		if (ret < 0)
 			return ret;
 		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
 				  &regvall);
 		if (ret < 0)
 			return ret;
 		*val = (regvalh - regvall) * 1000;
 		return 0;
 	case hwmon_temp_crit_hyst:
 		regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
 				 LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
 		ret = regmap_read(regmap, regh, &regvalh);
 		if (ret < 0)
 			return ret;
 		ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
 				  &regvall);
 		if (ret < 0)
 			return ret;
 		*val = (regvalh - regvall) * 1000;
 		return 0;
 	case hwmon_temp_type:
 		ret = regmap_read(regmap, LM95245_REG_RW_CONFIG2, &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = (regvalh & CFG2_REMOTE_TT) ? 1 : 2;
 		return 0;
 	case hwmon_temp_offset:
 		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFL,
 				  &regvall);
 		if (ret < 0)
 			return ret;
 		ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFH,
 				  &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = temp_from_reg_signed(regvalh, regvall);
 		return 0;
 	case hwmon_temp_max_alarm:
 		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = !!(regvalh & STATUS1_ROS);
 		return 0;
 	case hwmon_temp_crit_alarm:
 		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = !!(regvalh & (channel ? STATUS1_RTCRIT : STATUS1_LOC));
 		return 0;
 	case hwmon_temp_fault:
 		ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
 		if (ret < 0)
 			return ret;
 		*val = !!(regvalh & STATUS1_DIODE_FAULT);
 		return 0;
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm95245_write_temp(struct device *dev, u32 attr, int channel,
 			      long val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
 	struct regmap *regmap = data->regmap;
 	unsigned int regval;
 	int ret, reg;

 	switch (attr) {
 	case hwmon_temp_max:
 		val = clamp_val(val / 1000, 0, 255);
 		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT, val);
 		return ret;
 	case hwmon_temp_crit:
 		reg = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
 				LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
 		val = clamp_val(val / 1000, 0, channel ? 255 : 127);
 		ret = regmap_write(regmap, reg, val);
 		return ret;
 	case hwmon_temp_crit_hyst:
 		mutex_lock(&data->update_lock);
 		ret = regmap_read(regmap, LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
 				  &regval);
 		if (ret < 0) {
 			mutex_unlock(&data->update_lock);
 			return ret;
 		}
 		/* Clamp to reasonable range to prevent overflow */
 		val = clamp_val(val, -1000000, 1000000);
 		val = regval - val / 1000;
 		val = clamp_val(val, 0, 31);
 		ret = regmap_write(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
 				   val);
 		mutex_unlock(&data->update_lock);
 		return ret;
 	case hwmon_temp_offset:
 		val = clamp_val(val, -128000, 127875);
 		val = val * 256 / 1000;
 		mutex_lock(&data->update_lock);
 		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFL,
 				   val & 0xe0);
 		if (ret < 0) {
 			mutex_unlock(&data->update_lock);
 			return ret;
 		}
 		ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFH,
 				   (val >> 8) & 0xff);
 		mutex_unlock(&data->update_lock);
 		return ret;
 	case hwmon_temp_type:
 		if (val != 1 && val != 2)
 			return -EINVAL;
 		ret = regmap_update_bits(regmap, LM95245_REG_RW_CONFIG2,
 					 CFG2_REMOTE_TT,
 					 val == 1 ? CFG2_REMOTE_TT : 0);
 		return ret;
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm95245_read_chip(struct device *dev, u32 attr, int channel,
 			     long *val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);

 	switch (attr) {
 	case hwmon_chip_update_interval:
 		*val = data->interval;
 		return 0;
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm95245_write_chip(struct device *dev, u32 attr, int channel,
 			      long val)
 {
 	struct lm95245_data *data = dev_get_drvdata(dev);
 	int ret;

 	switch (attr) {
 	case hwmon_chip_update_interval:
 		mutex_lock(&data->update_lock);
 		ret = lm95245_set_conversion_rate(data, val);
 		mutex_unlock(&data->update_lock);
 		return ret;
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm95245_read(struct device *dev, enum hwmon_sensor_types type,
 			u32 attr, int channel, long *val)
 {
 	switch (type) {
 	case hwmon_chip:
 		return lm95245_read_chip(dev, attr, channel, val);
 	case hwmon_temp:
 		return lm95245_read_temp(dev, attr, channel, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm95245_write(struct device *dev, enum hwmon_sensor_types type,
 			 u32 attr, int channel, long val)
 {
 	switch (type) {
 	case hwmon_chip:
 		return lm95245_write_chip(dev, attr, channel, val);
 	case hwmon_temp:
 		return lm95245_write_temp(dev, attr, channel, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static umode_t lm95245_temp_is_visible(const void *data, u32 attr, int channel)
 {
 	switch (attr) {
 	case hwmon_temp_input:
 	case hwmon_temp_max_alarm:
 	case hwmon_temp_max_hyst:
 	case hwmon_temp_crit_alarm:
 	case hwmon_temp_fault:
 		return 0444;
 	case hwmon_temp_type:
 	case hwmon_temp_max:
 	case hwmon_temp_crit:
 	case hwmon_temp_offset:
 		return 0644;
 	case hwmon_temp_crit_hyst:
 		return (channel == 0) ? 0644 : 0444;
 	default:
 		return 0;
 	}
 }

 static umode_t lm95245_is_visible(const void *data,
 				  enum hwmon_sensor_types type,
 				  u32 attr, int channel)
 {
 	switch (type) {
 	case hwmon_chip:
 		switch (attr) {
 		case hwmon_chip_update_interval:
 			return 0644;
 		default:
 			return 0;
 		}
 	case hwmon_temp:
 		return lm95245_temp_is_visible(data, attr, channel);
 	default:
 		return 0;
 	}
 }

 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int lm95245_detect(struct i2c_client *new_client,
 			  struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = new_client->adapter;
 	int address = new_client->addr;
 	const char *name;
 	int rev, id;

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

 	id = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID);
 	if (id != MANUFACTURER_ID)
 		return -ENODEV;

 	rev = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID);
 	switch (rev) {
 	case LM95235_REVISION:
 		if (address != 0x18 && address != 0x29 && address != 0x4c)
 			return -ENODEV;
 		name = "lm95235";
 		break;
 	case LM95245_REVISION:
 		name = "lm95245";
 		break;
 	default:
 		return -ENODEV;
 	}

 	strlcpy(info->type, name, I2C_NAME_SIZE);
 	return 0;
 }

 static int lm95245_init_client(struct lm95245_data *data)
 {
 	int ret;

 	ret = lm95245_read_conversion_rate(data);
 	if (ret < 0)
 		return ret;

 	return regmap_update_bits(data->regmap, LM95245_REG_RW_CONFIG1,
 				  CFG_STOP, 0);
 }

 static bool lm95245_is_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case LM95245_REG_RW_CONFIG1:
 	case LM95245_REG_RW_CONVERS_RATE:
 	case LM95245_REG_W_ONE_SHOT:
 	case LM95245_REG_RW_CONFIG2:
 	case LM95245_REG_RW_REMOTE_OFFH:
 	case LM95245_REG_RW_REMOTE_OFFL:
 	case LM95245_REG_RW_REMOTE_OS_LIMIT:
 	case LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT:
 	case LM95245_REG_RW_REMOTE_TCRIT_LIMIT:
 	case LM95245_REG_RW_COMMON_HYSTERESIS:
 		return true;
 	default:
 		return false;
 	}
 }

 static bool lm95245_is_volatile_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case LM95245_REG_R_STATUS1:
 	case LM95245_REG_R_STATUS2:
 	case LM95245_REG_R_LOCAL_TEMPH_S:
 	case LM95245_REG_R_LOCAL_TEMPL_S:
 	case LM95245_REG_R_REMOTE_TEMPH_S:
 	case LM95245_REG_R_REMOTE_TEMPL_S:
 	case LM95245_REG_R_REMOTE_TEMPH_U:
 	case LM95245_REG_R_REMOTE_TEMPL_U:
 		return true;
 	default:
 		return false;
 	}
 }

 static const struct regmap_config lm95245_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.writeable_reg = lm95245_is_writeable_reg,
 	.volatile_reg = lm95245_is_volatile_reg,
 	.cache_type = REGCACHE_RBTREE,
 	.use_single_read = true,
 	.use_single_write = true,
 };

 static const struct hwmon_channel_info *lm95245_info[] = {
 	HWMON_CHANNEL_INFO(chip,
 			   HWMON_C_UPDATE_INTERVAL),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_HYST |
 			   HWMON_T_CRIT_ALARM,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST |
 			   HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_FAULT |
 			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
 			   HWMON_T_TYPE | HWMON_T_OFFSET),
 	NULL
 };

 static const struct hwmon_ops lm95245_hwmon_ops = {
 	.is_visible = lm95245_is_visible,
 	.read = lm95245_read,
 	.write = lm95245_write,
 };

 static const struct hwmon_chip_info lm95245_chip_info = {
 	.ops = &lm95245_hwmon_ops,
 	.info = lm95245_info,
 };

 static int lm95245_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct device *dev = &client->dev;
 	struct lm95245_data *data;
 	struct device *hwmon_dev;
 	int ret;

 	data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->regmap = devm_regmap_init_i2c(client, &lm95245_regmap_config);
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);

 	mutex_init(&data->update_lock);

 	/* Initialize the LM95245 chip */
 	ret = lm95245_init_client(data);
 	if (ret < 0)
 		return ret;

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 							 data,
 							 &lm95245_chip_info,
 							 NULL);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 /* Driver data (common to all clients) */
 static const struct i2c_device_id lm95245_id[] = {
 	{ "lm95235", 0 },
 	{ "lm95245", 0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, lm95245_id);

 static const struct of_device_id __maybe_unused lm95245_of_match[] = {
 	{ .compatible = "national,lm95235" },
 	{ .compatible = "national,lm95245" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, lm95245_of_match);

 static struct i2c_driver lm95245_driver = {
 	.class		= I2C_CLASS_HWMON,
 	.driver = {
 		.name	= "lm95245",
 		.of_match_table = of_match_ptr(lm95245_of_match),
 	},
 	.probe		= lm95245_probe,
 	.id_table	= lm95245_id,
 	.detect		= lm95245_detect,
 	.address_list	= normal_i2c,
 };

 module_i2c_driver(lm95245_driver);

 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
 MODULE_DESCRIPTION("LM95235/LM95245 sensor driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
	*
	* The LM95245 is a sensor chip made by TI / National Semiconductor.
	* It reports up to two temperatures (its own plus an external one).
	*
	* This driver is based on lm95241.c
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

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

	static const unsigned short normal_i2c[] = {
	0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };

	/* LM95245 registers */
	/* general registers */
	#define LM95245_REG_RW_CONFIG1 0x03
	#define LM95245_REG_RW_CONVERS_RATE 0x04
	#define LM95245_REG_W_ONE_SHOT 0x0F

	/* diode configuration */
	#define LM95245_REG_RW_CONFIG2 0xBF
	#define LM95245_REG_RW_REMOTE_OFFH 0x11
	#define LM95245_REG_RW_REMOTE_OFFL 0x12

	/* status registers */
	#define LM95245_REG_R_STATUS1 0x02
	#define LM95245_REG_R_STATUS2 0x33

	/* limit registers */
	#define LM95245_REG_RW_REMOTE_OS_LIMIT 0x07
	#define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT 0x20
	#define LM95245_REG_RW_REMOTE_TCRIT_LIMIT 0x19
	#define LM95245_REG_RW_COMMON_HYSTERESIS 0x21

	/* temperature signed */
	#define LM95245_REG_R_LOCAL_TEMPH_S 0x00
	#define LM95245_REG_R_LOCAL_TEMPL_S 0x30
	#define LM95245_REG_R_REMOTE_TEMPH_S 0x01
	#define LM95245_REG_R_REMOTE_TEMPL_S 0x10
	/* temperature unsigned */
	#define LM95245_REG_R_REMOTE_TEMPH_U 0x31
	#define LM95245_REG_R_REMOTE_TEMPL_U 0x32

	/* id registers */
	#define LM95245_REG_R_MAN_ID 0xFE
	#define LM95245_REG_R_CHIP_ID 0xFF

	/* LM95245 specific bitfields */
	#define CFG_STOP 0x40
	#define CFG_REMOTE_TCRIT_MASK 0x10
	#define CFG_REMOTE_OS_MASK 0x08
	#define CFG_LOCAL_TCRIT_MASK 0x04
	#define CFG_LOCAL_OS_MASK 0x02

	#define CFG2_OS_A0 0x40
	#define CFG2_DIODE_FAULT_OS 0x20
	#define CFG2_DIODE_FAULT_TCRIT 0x10
	#define CFG2_REMOTE_TT 0x08
	#define CFG2_REMOTE_FILTER_DIS 0x00
	#define CFG2_REMOTE_FILTER_EN 0x06

	/* conversation rate in ms */
	#define RATE_CR0063 0x00
	#define RATE_CR0364 0x01
	#define RATE_CR1000 0x02
	#define RATE_CR2500 0x03

	#define STATUS1_ROS 0x10
	#define STATUS1_DIODE_FAULT 0x04
	#define STATUS1_RTCRIT 0x02
	#define STATUS1_LOC 0x01

	#define MANUFACTURER_ID 0x01
	#define LM95235_REVISION 0xB1
	#define LM95245_REVISION 0xB3

	/* Client data (each client gets its own) */
	struct lm95245_data {
	struct regmap *regmap;
	struct mutex update_lock;
	int interval; /* in msecs */
	};

	/* Conversions */
	static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
	{
	return val_h * 1000 + val_l * 1000 / 256;
	}

	static int temp_from_reg_signed(u8 val_h, u8 val_l)
	{
	if (val_h & 0x80)
	return (val_h - 0x100) * 1000;
	return temp_from_reg_unsigned(val_h, val_l);
	}

	static int lm95245_read_conversion_rate(struct lm95245_data *data)
	{
	unsigned int rate;
	int ret;

	ret = regmap_read(data->regmap, LM95245_REG_RW_CONVERS_RATE, &rate);
	if (ret < 0)
	return ret;

	switch (rate) {
	case RATE_CR0063:
	data->interval = 63;
	break;
	case RATE_CR0364:
	data->interval = 364;
	break;
	case RATE_CR1000:
	data->interval = 1000;
	break;
	case RATE_CR2500:
	default:
	data->interval = 2500;
	break;
	}
	return 0;
	}

	static int lm95245_set_conversion_rate(struct lm95245_data *data, long interval)
	{
	int ret, rate;

	if (interval <= 63) {
	interval = 63;
	rate = RATE_CR0063;
	} else if (interval <= 364) {
	interval = 364;
	rate = RATE_CR0364;
	} else if (interval <= 1000) {
	interval = 1000;
	rate = RATE_CR1000;
	} else {
	interval = 2500;
	rate = RATE_CR2500;
	}

	ret = regmap_write(data->regmap, LM95245_REG_RW_CONVERS_RATE, rate);
	if (ret < 0)
	return ret;

	data->interval = interval;
	return 0;
	}

	static int lm95245_read_temp(struct device *dev, u32 attr, int channel,
	long *val)
	{
	struct lm95245_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret, regl, regh, regvall, regvalh;

	switch (attr) {
	case hwmon_temp_input:
	regl = channel ? LM95245_REG_R_REMOTE_TEMPL_S :
	LM95245_REG_R_LOCAL_TEMPL_S;
	regh = channel ? LM95245_REG_R_REMOTE_TEMPH_S :
	LM95245_REG_R_LOCAL_TEMPH_S;
	ret = regmap_read(regmap, regl, &regvall);
	if (ret < 0)
	return ret;
	ret = regmap_read(regmap, regh, &regvalh);
	if (ret < 0)
	return ret;
	/*
	* Local temp is always signed.
	* Remote temp has both signed and unsigned data.
	* Use signed calculation for remote if signed bit is set
	* or if reported temperature is below signed limit.
	*/
	if (!channel \|\| (regvalh & 0x80) \|\| regvalh < 0x7f) {
	*val = temp_from_reg_signed(regvalh, regvall);
	return 0;
	}
	ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPL_U,
	&regvall);
	if (ret < 0)
	return ret;
	ret = regmap_read(regmap, LM95245_REG_R_REMOTE_TEMPH_U,
	&regvalh);
	if (ret < 0)
	return ret;
	*val = temp_from_reg_unsigned(regvalh, regvall);
	return 0;
	case hwmon_temp_max:
	ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
	&regvalh);
	if (ret < 0)
	return ret;
	val = regvalh 1000;
	return 0;
	case hwmon_temp_crit:
	regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
	LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
	ret = regmap_read(regmap, regh, &regvalh);
	if (ret < 0)
	return ret;
	val = regvalh 1000;
	return 0;
	case hwmon_temp_max_hyst:
	ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
	&regvalh);
	if (ret < 0)
	return ret;
	ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
	&regvall);
	if (ret < 0)
	return ret;
	val = (regvalh - regvall) 1000;
	return 0;
	case hwmon_temp_crit_hyst:
	regh = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
	LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
	ret = regmap_read(regmap, regh, &regvalh);
	if (ret < 0)
	return ret;
	ret = regmap_read(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
	&regvall);
	if (ret < 0)
	return ret;
	val = (regvalh - regvall) 1000;
	return 0;
	case hwmon_temp_type:
	ret = regmap_read(regmap, LM95245_REG_RW_CONFIG2, &regvalh);
	if (ret < 0)
	return ret;
	*val = (regvalh & CFG2_REMOTE_TT) ? 1 : 2;
	return 0;
	case hwmon_temp_offset:
	ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFL,
	&regvall);
	if (ret < 0)
	return ret;
	ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OFFH,
	&regvalh);
	if (ret < 0)
	return ret;
	*val = temp_from_reg_signed(regvalh, regvall);
	return 0;
	case hwmon_temp_max_alarm:
	ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
	if (ret < 0)
	return ret;
	*val = !!(regvalh & STATUS1_ROS);
	return 0;
	case hwmon_temp_crit_alarm:
	ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
	if (ret < 0)
	return ret;
	*val = !!(regvalh & (channel ? STATUS1_RTCRIT : STATUS1_LOC));
	return 0;
	case hwmon_temp_fault:
	ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regvalh);
	if (ret < 0)
	return ret;
	*val = !!(regvalh & STATUS1_DIODE_FAULT);
	return 0;
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm95245_write_temp(struct device *dev, u32 attr, int channel,
	long val)
	{
	struct lm95245_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	unsigned int regval;
	int ret, reg;

	switch (attr) {
	case hwmon_temp_max:
	val = clamp_val(val / 1000, 0, 255);
	ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT, val);
	return ret;
	case hwmon_temp_crit:
	reg = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
	LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
	val = clamp_val(val / 1000, 0, channel ? 255 : 127);
	ret = regmap_write(regmap, reg, val);
	return ret;
	case hwmon_temp_crit_hyst:
	mutex_lock(&data->update_lock);
	ret = regmap_read(regmap, LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
	&regval);
	if (ret < 0) {
	mutex_unlock(&data->update_lock);
	return ret;
	}
	/* Clamp to reasonable range to prevent overflow */
	val = clamp_val(val, -1000000, 1000000);
	val = regval - val / 1000;
	val = clamp_val(val, 0, 31);
	ret = regmap_write(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
	val);
	mutex_unlock(&data->update_lock);
	return ret;
	case hwmon_temp_offset:
	val = clamp_val(val, -128000, 127875);
	val = val * 256 / 1000;
	mutex_lock(&data->update_lock);
	ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFL,
	val & 0xe0);
	if (ret < 0) {
	mutex_unlock(&data->update_lock);
	return ret;
	}
	ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OFFH,
	(val >> 8) & 0xff);
	mutex_unlock(&data->update_lock);
	return ret;
	case hwmon_temp_type:
	if (val != 1 && val != 2)
	return -EINVAL;
	ret = regmap_update_bits(regmap, LM95245_REG_RW_CONFIG2,
	CFG2_REMOTE_TT,
	val == 1 ? CFG2_REMOTE_TT : 0);
	return ret;
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm95245_read_chip(struct device *dev, u32 attr, int channel,
	long *val)
	{
	struct lm95245_data *data = dev_get_drvdata(dev);

	switch (attr) {
	case hwmon_chip_update_interval:
	*val = data->interval;
	return 0;
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm95245_write_chip(struct device *dev, u32 attr, int channel,
	long val)
	{
	struct lm95245_data *data = dev_get_drvdata(dev);
	int ret;

	switch (attr) {
	case hwmon_chip_update_interval:
	mutex_lock(&data->update_lock);
	ret = lm95245_set_conversion_rate(data, val);
	mutex_unlock(&data->update_lock);
	return ret;
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm95245_read(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long *val)
	{
	switch (type) {
	case hwmon_chip:
	return lm95245_read_chip(dev, attr, channel, val);
	case hwmon_temp:
	return lm95245_read_temp(dev, attr, channel, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm95245_write(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long val)
	{
	switch (type) {
	case hwmon_chip:
	return lm95245_write_chip(dev, attr, channel, val);
	case hwmon_temp:
	return lm95245_write_temp(dev, attr, channel, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static umode_t lm95245_temp_is_visible(const void *data, u32 attr, int channel)
	{
	switch (attr) {
	case hwmon_temp_input:
	case hwmon_temp_max_alarm:
	case hwmon_temp_max_hyst:
	case hwmon_temp_crit_alarm:
	case hwmon_temp_fault:
	return 0444;
	case hwmon_temp_type:
	case hwmon_temp_max:
	case hwmon_temp_crit:
	case hwmon_temp_offset:
	return 0644;
	case hwmon_temp_crit_hyst:
	return (channel == 0) ? 0644 : 0444;
	default:
	return 0;
	}
	}

	static umode_t lm95245_is_visible(const void *data,
	enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	switch (type) {
	case hwmon_chip:
	switch (attr) {
	case hwmon_chip_update_interval:
	return 0644;
	default:
	return 0;
	}
	case hwmon_temp:
	return lm95245_temp_is_visible(data, attr, channel);
	default:
	return 0;
	}
	}

	/* Return 0 if detection is successful, -ENODEV otherwise */
	static int lm95245_detect(struct i2c_client *new_client,
	struct i2c_board_info *info)
	{
	struct i2c_adapter *adapter = new_client->adapter;
	int address = new_client->addr;
	const char *name;
	int rev, id;

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

	id = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID);
	if (id != MANUFACTURER_ID)
	return -ENODEV;

	rev = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID);
	switch (rev) {
	case LM95235_REVISION:
	if (address != 0x18 && address != 0x29 && address != 0x4c)
	return -ENODEV;
	name = "lm95235";
	break;
	case LM95245_REVISION:
	name = "lm95245";
	break;
	default:
	return -ENODEV;
	}

	strlcpy(info->type, name, I2C_NAME_SIZE);
	return 0;
	}

	static int lm95245_init_client(struct lm95245_data *data)
	{
	int ret;

	ret = lm95245_read_conversion_rate(data);
	if (ret < 0)
	return ret;

	return regmap_update_bits(data->regmap, LM95245_REG_RW_CONFIG1,
	CFG_STOP, 0);
	}

	static bool lm95245_is_writeable_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case LM95245_REG_RW_CONFIG1:
	case LM95245_REG_RW_CONVERS_RATE:
	case LM95245_REG_W_ONE_SHOT:
	case LM95245_REG_RW_CONFIG2:
	case LM95245_REG_RW_REMOTE_OFFH:
	case LM95245_REG_RW_REMOTE_OFFL:
	case LM95245_REG_RW_REMOTE_OS_LIMIT:
	case LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT:
	case LM95245_REG_RW_REMOTE_TCRIT_LIMIT:
	case LM95245_REG_RW_COMMON_HYSTERESIS:
	return true;
	default:
	return false;
	}
	}

	static bool lm95245_is_volatile_reg(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case LM95245_REG_R_STATUS1:
	case LM95245_REG_R_STATUS2:
	case LM95245_REG_R_LOCAL_TEMPH_S:
	case LM95245_REG_R_LOCAL_TEMPL_S:
	case LM95245_REG_R_REMOTE_TEMPH_S:
	case LM95245_REG_R_REMOTE_TEMPL_S:
	case LM95245_REG_R_REMOTE_TEMPH_U:
	case LM95245_REG_R_REMOTE_TEMPL_U:
	return true;
	default:
	return false;
	}
	}

	static const struct regmap_config lm95245_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.writeable_reg = lm95245_is_writeable_reg,
	.volatile_reg = lm95245_is_volatile_reg,
	.cache_type = REGCACHE_RBTREE,
	.use_single_read = true,
	.use_single_write = true,
	};

	static const struct hwmon_channel_info *lm95245_info[] = {
	HWMON_CHANNEL_INFO(chip,
	HWMON_C_UPDATE_INTERVAL),
	HWMON_CHANNEL_INFO(temp,
	HWMON_T_INPUT \| HWMON_T_CRIT \| HWMON_T_CRIT_HYST \|
	HWMON_T_CRIT_ALARM,
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_MAX_HYST \|
	HWMON_T_CRIT \| HWMON_T_CRIT_HYST \| HWMON_T_FAULT \|
	HWMON_T_MAX_ALARM \| HWMON_T_CRIT_ALARM \|
	HWMON_T_TYPE \| HWMON_T_OFFSET),
	NULL
	};

	static const struct hwmon_ops lm95245_hwmon_ops = {
	.is_visible = lm95245_is_visible,
	.read = lm95245_read,
	.write = lm95245_write,
	};

	static const struct hwmon_chip_info lm95245_chip_info = {
	.ops = &lm95245_hwmon_ops,
	.info = lm95245_info,
	};

	static int lm95245_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct device *dev = &client->dev;
	struct lm95245_data *data;
	struct device *hwmon_dev;
	int ret;

	data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->regmap = devm_regmap_init_i2c(client, &lm95245_regmap_config);
	if (IS_ERR(data->regmap))
	return PTR_ERR(data->regmap);

	mutex_init(&data->update_lock);

	/* Initialize the LM95245 chip */
	ret = lm95245_init_client(data);
	if (ret < 0)
	return ret;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
	data,
	&lm95245_chip_info,
	NULL);
	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	/* Driver data (common to all clients) */
	static const struct i2c_device_id lm95245_id[] = {
	{ "lm95235", 0 },
	{ "lm95245", 0 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, lm95245_id);

	static const struct of_device_id __maybe_unused lm95245_of_match[] = {
	{ .compatible = "national,lm95235" },
	{ .compatible = "national,lm95245" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, lm95245_of_match);

	static struct i2c_driver lm95245_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "lm95245",
	.of_match_table = of_match_ptr(lm95245_of_match),
	},
	.probe = lm95245_probe,
	.id_table = lm95245_id,
	.detect = lm95245_detect,
	.address_list = normal_i2c,
	};

	module_i2c_driver(lm95245_driver);

	MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
	MODULE_DESCRIPTION("LM95235/LM95245 sensor driver");
	MODULE_LICENSE("GPL");