drivers/hwmon/lm83.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * lm83.c - Part of lm_sensors, Linux kernel modules for hardware
  *          monitoring
  * Copyright (C) 2003-2009  Jean Delvare <jdelvare@suse.de>
  *
  * Heavily inspired from the lm78, lm75 and adm1021 drivers. The LM83 is
  * a sensor chip made by National Semiconductor. It reports up to four
  * temperatures (its own plus up to three external ones) with a 1 deg
  * resolution and a 3-4 deg accuracy. Complete datasheet can be obtained
  * from National's website at:
  *   http://www.national.com/pf/LM/LM83.html
  * Since the datasheet omits to give the chip stepping code, I give it
  * here: 0x03 (at register 0xff).
  *
  * Also supports the LM82 temp sensor, which is basically a stripped down
  * model of the LM83.  Datasheet is here:
  * http://www.national.com/pf/LM/LM82.html
  */

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

 /*
  * Addresses to scan
  * Address is selected using 2 three-level pins, resulting in 9 possible
  * addresses.
  */

 static const unsigned short normal_i2c[] = {
 	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

 enum chips { lm83, lm82 };

 /*
  * The LM83 registers
  * Manufacturer ID is 0x01 for National Semiconductor.
  */

 #define LM83_REG_R_MAN_ID		0xFE
 #define LM83_REG_R_CHIP_ID		0xFF
 #define LM83_REG_R_CONFIG		0x03
 #define LM83_REG_W_CONFIG		0x09
 #define LM83_REG_R_STATUS1		0x02
 #define LM83_REG_R_STATUS2		0x35
 #define LM83_REG_R_LOCAL_TEMP		0x00
 #define LM83_REG_R_LOCAL_HIGH		0x05
 #define LM83_REG_W_LOCAL_HIGH		0x0B
 #define LM83_REG_R_REMOTE1_TEMP		0x30
 #define LM83_REG_R_REMOTE1_HIGH		0x38
 #define LM83_REG_W_REMOTE1_HIGH		0x50
 #define LM83_REG_R_REMOTE2_TEMP		0x01
 #define LM83_REG_R_REMOTE2_HIGH		0x07
 #define LM83_REG_W_REMOTE2_HIGH		0x0D
 #define LM83_REG_R_REMOTE3_TEMP		0x31
 #define LM83_REG_R_REMOTE3_HIGH		0x3A
 #define LM83_REG_W_REMOTE3_HIGH		0x52
 #define LM83_REG_R_TCRIT		0x42
 #define LM83_REG_W_TCRIT		0x5A

 static const u8 LM83_REG_TEMP[] = {
 	LM83_REG_R_LOCAL_TEMP,
 	LM83_REG_R_REMOTE1_TEMP,
 	LM83_REG_R_REMOTE2_TEMP,
 	LM83_REG_R_REMOTE3_TEMP,
 };

 static const u8 LM83_REG_MAX[] = {
 	LM83_REG_R_LOCAL_HIGH,
 	LM83_REG_R_REMOTE1_HIGH,
 	LM83_REG_R_REMOTE2_HIGH,
 	LM83_REG_R_REMOTE3_HIGH,
 };

 /* alarm and fault registers and bits, indexed by channel */
 static const u8 LM83_ALARM_REG[] = {
 	LM83_REG_R_STATUS1, LM83_REG_R_STATUS2, LM83_REG_R_STATUS1, LM83_REG_R_STATUS2
 };

 static const u8 LM83_MAX_ALARM_BIT[] = {
 	BIT(6), BIT(7), BIT(4), BIT(4)
 };

 static const u8 LM83_CRIT_ALARM_BIT[] = {
 	BIT(0), BIT(0), BIT(1), BIT(1)
 };

 static const u8 LM83_FAULT_BIT[] = {
 	0, BIT(5), BIT(2), BIT(2)
 };

 /*
  * Client data (each client gets its own)
  */

 struct lm83_data {
 	struct regmap *regmap;
 	enum chips type;
 };

 /* regmap code */

 static int lm83_regmap_reg_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct i2c_client *client = context;
 	int ret;

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

 	*val = ret;
 	return 0;
 }

 /*
  * The regmap write function maps read register addresses to write register
  * addresses. This is necessary for regmap register caching to work.
  * An alternative would be to clear the regmap cache whenever a register is
  * written, but that would be much more expensive.
  */
 static int lm83_regmap_reg_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct i2c_client *client = context;

 	switch (reg) {
 	case LM83_REG_R_CONFIG:
 	case LM83_REG_R_LOCAL_HIGH:
 	case LM83_REG_R_REMOTE2_HIGH:
 		reg += 0x06;
 		break;
 	case LM83_REG_R_REMOTE1_HIGH:
 	case LM83_REG_R_REMOTE3_HIGH:
 	case LM83_REG_R_TCRIT:
 		reg += 0x18;
 		break;
 	default:
 		break;
 	}

 	return i2c_smbus_write_byte_data(client, reg, val);
 }

 static bool lm83_regmap_is_volatile(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
 	case LM83_REG_R_LOCAL_TEMP:
 	case LM83_REG_R_REMOTE1_TEMP:
 	case LM83_REG_R_REMOTE2_TEMP:
 	case LM83_REG_R_REMOTE3_TEMP:
 	case LM83_REG_R_STATUS1:
 	case LM83_REG_R_STATUS2:
 		return true;
 	default:
 		return false;
 	}
 }

 static const struct regmap_config lm83_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
 	.cache_type = REGCACHE_RBTREE,
 	.volatile_reg = lm83_regmap_is_volatile,
 	.reg_read = lm83_regmap_reg_read,
 	.reg_write = lm83_regmap_reg_write,
 };

 /* hwmon API */

 static int lm83_temp_read(struct device *dev, u32 attr, int channel, long *val)
 {
 	struct lm83_data *data = dev_get_drvdata(dev);
 	unsigned int regval;
 	int err;

 	switch (attr) {
 	case hwmon_temp_input:
 		err = regmap_read(data->regmap, LM83_REG_TEMP[channel], &regval);
 		if (err < 0)
 			return err;
 		*val = (s8)regval * 1000;
 		break;
 	case hwmon_temp_max:
 		err = regmap_read(data->regmap, LM83_REG_MAX[channel], &regval);
 		if (err < 0)
 			return err;
 		*val = (s8)regval * 1000;
 		break;
 	case hwmon_temp_crit:
 		err = regmap_read(data->regmap, LM83_REG_R_TCRIT, &regval);
 		if (err < 0)
 			return err;
 		*val = (s8)regval * 1000;
 		break;
 	case hwmon_temp_max_alarm:
 		err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
 		if (err < 0)
 			return err;
 		*val = !!(regval & LM83_MAX_ALARM_BIT[channel]);
 		break;
 	case hwmon_temp_crit_alarm:
 		err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
 		if (err < 0)
 			return err;
 		*val = !!(regval & LM83_CRIT_ALARM_BIT[channel]);
 		break;
 	case hwmon_temp_fault:
 		err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
 		if (err < 0)
 			return err;
 		*val = !!(regval & LM83_FAULT_BIT[channel]);
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 	return 0;
 }

 static int lm83_temp_write(struct device *dev, u32 attr, int channel, long val)
 {
 	struct lm83_data *data = dev_get_drvdata(dev);
 	unsigned int regval;
 	int err;

 	regval = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);

 	switch (attr) {
 	case hwmon_temp_max:
 		err = regmap_write(data->regmap, LM83_REG_MAX[channel], regval);
 		if (err < 0)
 			return err;
 		break;
 	case hwmon_temp_crit:
 		err = regmap_write(data->regmap, LM83_REG_R_TCRIT, regval);
 		if (err < 0)
 			return err;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 	return 0;
 }

 static int lm83_chip_read(struct device *dev, u32 attr, int channel, long *val)
 {
 	struct lm83_data *data = dev_get_drvdata(dev);
 	unsigned int regval;
 	int err;

 	switch (attr) {
 	case hwmon_chip_alarms:
 		err = regmap_read(data->regmap, LM83_REG_R_STATUS1, &regval);
 		if (err < 0)
 			return err;
 		*val = regval;
 		err = regmap_read(data->regmap, LM83_REG_R_STATUS2, &regval);
 		if (err < 0)
 			return err;
 		*val |= regval << 8;
 		return 0;
 	default:
 		return -EOPNOTSUPP;
 	}

 	return 0;
 }

 static int lm83_read(struct device *dev, enum hwmon_sensor_types type,
 		     u32 attr, int channel, long *val)
 {
 	switch (type) {
 	case hwmon_chip:
 		return lm83_chip_read(dev, attr, channel, val);
 	case hwmon_temp:
 		return lm83_temp_read(dev, attr, channel, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static int lm83_write(struct device *dev, enum hwmon_sensor_types type,
 		      u32 attr, int channel, long val)
 {
 	switch (type) {
 	case hwmon_temp:
 		return lm83_temp_write(dev, attr, channel, val);
 	default:
 		return -EOPNOTSUPP;
 	}
 }

 static umode_t lm83_is_visible(const void *_data, enum hwmon_sensor_types type,
 			       u32 attr, int channel)
 {
 	const struct lm83_data *data = _data;

 	/*
 	 * LM82 only supports a single external channel, modeled as channel 2.
 	 */
 	if (data->type == lm82 && (channel == 1 || channel == 3))
 		return 0;

 	switch (type) {
 	case hwmon_chip:
 		if (attr == hwmon_chip_alarms)
 			return 0444;
 		break;
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_input:
 		case hwmon_temp_max_alarm:
 		case hwmon_temp_crit_alarm:
 			return 0444;
 		case hwmon_temp_fault:
 			if (channel)
 				return 0444;
 			break;
 		case hwmon_temp_max:
 			return 0644;
 		case hwmon_temp_crit:
 			if (channel == 2)
 				return 0644;
 			return 0444;
 		default:
 			break;
 		}
 		break;
 	default:
 		break;
 	}
 	return 0;
 }

 static const struct hwmon_channel_info * const lm83_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
 			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
 			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
 			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
 			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM | HWMON_T_FAULT
 			   ),
 	NULL
 };

 static const struct hwmon_ops lm83_hwmon_ops = {
 	.is_visible = lm83_is_visible,
 	.read = lm83_read,
 	.write = lm83_write,
 };

 static const struct hwmon_chip_info lm83_chip_info = {
 	.ops = &lm83_hwmon_ops,
 	.info = lm83_info,
 };

 /* Return 0 if detection is successful, -ENODEV otherwise */
 static int lm83_detect(struct i2c_client *client,
 		       struct i2c_board_info *info)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	const char *name;
 	u8 man_id, chip_id;

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

 	/* Detection */
 	if ((i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS1) & 0xA8) ||
 	    (i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS2) & 0x48) ||
 	    (i2c_smbus_read_byte_data(client, LM83_REG_R_CONFIG) & 0x41)) {
 		dev_dbg(&adapter->dev, "LM83 detection failed at 0x%02x\n",
 			client->addr);
 		return -ENODEV;
 	}

 	/* Identification */
 	man_id = i2c_smbus_read_byte_data(client, LM83_REG_R_MAN_ID);
 	if (man_id != 0x01)	/* National Semiconductor */
 		return -ENODEV;

 	chip_id = i2c_smbus_read_byte_data(client, LM83_REG_R_CHIP_ID);
 	switch (chip_id) {
 	case 0x03:
 		/*
 		 * According to the LM82 datasheet dated March 2013, recent
 		 * revisions of LM82 have a die revision of 0x03. This was
 		 * confirmed with a real chip. Further details in this revision
 		 * of the LM82 datasheet strongly suggest that LM82 is just a
 		 * repackaged LM83. It is therefore impossible to distinguish
 		 * those chips from LM83, and they will be misdetected as LM83.
 		 */
 		name = "lm83";
 		break;
 	case 0x01:
 		name = "lm82";
 		break;
 	default:
 		/* identification failed */
 		dev_dbg(&adapter->dev,
 			"Unsupported chip (man_id=0x%02X, chip_id=0x%02X)\n",
 			man_id, chip_id);
 		return -ENODEV;
 	}

 	strscpy(info->type, name, I2C_NAME_SIZE);

 	return 0;
 }

 static const struct i2c_device_id lm83_id[] = {
 	{ "lm83", lm83 },
 	{ "lm82", lm82 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, lm83_id);

 static int lm83_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct lm83_data *data;

 	data = devm_kzalloc(dev, sizeof(struct lm83_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->regmap = devm_regmap_init(dev, NULL, client, &lm83_regmap_config);
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);

 	data->type = i2c_match_id(lm83_id, client)->driver_data;

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
 							 data, &lm83_chip_info, NULL);
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 /*
  * Driver data (common to all clients)
  */

 static struct i2c_driver lm83_driver = {
 	.class		= I2C_CLASS_HWMON,
 	.driver = {
 		.name	= "lm83",
 	},
 	.probe_new	= lm83_probe,
 	.id_table	= lm83_id,
 	.detect		= lm83_detect,
 	.address_list	= normal_i2c,
 };

 module_i2c_driver(lm83_driver);

 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 MODULE_DESCRIPTION("LM83 driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* lm83.c - Part of lm_sensors, Linux kernel modules for hardware
	* monitoring
	* Copyright (C) 2003-2009 Jean Delvare <jdelvare@suse.de>
	*
	* Heavily inspired from the lm78, lm75 and adm1021 drivers. The LM83 is
	* a sensor chip made by National Semiconductor. It reports up to four
	* temperatures (its own plus up to three external ones) with a 1 deg
	* resolution and a 3-4 deg accuracy. Complete datasheet can be obtained
	* from National's website at:
	* http://www.national.com/pf/LM/LM83.html
	* Since the datasheet omits to give the chip stepping code, I give it
	* here: 0x03 (at register 0xff).
	*
	* Also supports the LM82 temp sensor, which is basically a stripped down
	* model of the LM83. Datasheet is here:
	* http://www.national.com/pf/LM/LM82.html
	*/

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

	/*
	* Addresses to scan
	* Address is selected using 2 three-level pins, resulting in 9 possible
	* addresses.
	*/

	static const unsigned short normal_i2c[] = {
	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

	enum chips { lm83, lm82 };

	/*
	* The LM83 registers
	* Manufacturer ID is 0x01 for National Semiconductor.
	*/

	#define LM83_REG_R_MAN_ID 0xFE
	#define LM83_REG_R_CHIP_ID 0xFF
	#define LM83_REG_R_CONFIG 0x03
	#define LM83_REG_W_CONFIG 0x09
	#define LM83_REG_R_STATUS1 0x02
	#define LM83_REG_R_STATUS2 0x35
	#define LM83_REG_R_LOCAL_TEMP 0x00
	#define LM83_REG_R_LOCAL_HIGH 0x05
	#define LM83_REG_W_LOCAL_HIGH 0x0B
	#define LM83_REG_R_REMOTE1_TEMP 0x30
	#define LM83_REG_R_REMOTE1_HIGH 0x38
	#define LM83_REG_W_REMOTE1_HIGH 0x50
	#define LM83_REG_R_REMOTE2_TEMP 0x01
	#define LM83_REG_R_REMOTE2_HIGH 0x07
	#define LM83_REG_W_REMOTE2_HIGH 0x0D
	#define LM83_REG_R_REMOTE3_TEMP 0x31
	#define LM83_REG_R_REMOTE3_HIGH 0x3A
	#define LM83_REG_W_REMOTE3_HIGH 0x52
	#define LM83_REG_R_TCRIT 0x42
	#define LM83_REG_W_TCRIT 0x5A

	static const u8 LM83_REG_TEMP[] = {
	LM83_REG_R_LOCAL_TEMP,
	LM83_REG_R_REMOTE1_TEMP,
	LM83_REG_R_REMOTE2_TEMP,
	LM83_REG_R_REMOTE3_TEMP,
	};

	static const u8 LM83_REG_MAX[] = {
	LM83_REG_R_LOCAL_HIGH,
	LM83_REG_R_REMOTE1_HIGH,
	LM83_REG_R_REMOTE2_HIGH,
	LM83_REG_R_REMOTE3_HIGH,
	};

	/* alarm and fault registers and bits, indexed by channel */
	static const u8 LM83_ALARM_REG[] = {
	LM83_REG_R_STATUS1, LM83_REG_R_STATUS2, LM83_REG_R_STATUS1, LM83_REG_R_STATUS2
	};

	static const u8 LM83_MAX_ALARM_BIT[] = {
	BIT(6), BIT(7), BIT(4), BIT(4)
	};

	static const u8 LM83_CRIT_ALARM_BIT[] = {
	BIT(0), BIT(0), BIT(1), BIT(1)
	};

	static const u8 LM83_FAULT_BIT[] = {
	0, BIT(5), BIT(2), BIT(2)
	};

	/*
	* Client data (each client gets its own)
	*/

	struct lm83_data {
	struct regmap *regmap;
	enum chips type;
	};

	/* regmap code */

	static int lm83_regmap_reg_read(void context, unsigned int reg, unsigned int val)
	{
	struct i2c_client *client = context;
	int ret;

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

	*val = ret;
	return 0;
	}

	/*
	* The regmap write function maps read register addresses to write register
	* addresses. This is necessary for regmap register caching to work.
	* An alternative would be to clear the regmap cache whenever a register is
	* written, but that would be much more expensive.
	*/
	static int lm83_regmap_reg_write(void *context, unsigned int reg, unsigned int val)
	{
	struct i2c_client *client = context;

	switch (reg) {
	case LM83_REG_R_CONFIG:
	case LM83_REG_R_LOCAL_HIGH:
	case LM83_REG_R_REMOTE2_HIGH:
	reg += 0x06;
	break;
	case LM83_REG_R_REMOTE1_HIGH:
	case LM83_REG_R_REMOTE3_HIGH:
	case LM83_REG_R_TCRIT:
	reg += 0x18;
	break;
	default:
	break;
	}

	return i2c_smbus_write_byte_data(client, reg, val);
	}

	static bool lm83_regmap_is_volatile(struct device *dev, unsigned int reg)
	{
	switch (reg) {
	case LM83_REG_R_LOCAL_TEMP:
	case LM83_REG_R_REMOTE1_TEMP:
	case LM83_REG_R_REMOTE2_TEMP:
	case LM83_REG_R_REMOTE3_TEMP:
	case LM83_REG_R_STATUS1:
	case LM83_REG_R_STATUS2:
	return true;
	default:
	return false;
	}
	}

	static const struct regmap_config lm83_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.cache_type = REGCACHE_RBTREE,
	.volatile_reg = lm83_regmap_is_volatile,
	.reg_read = lm83_regmap_reg_read,
	.reg_write = lm83_regmap_reg_write,
	};

	/* hwmon API */

	static int lm83_temp_read(struct device dev, u32 attr, int channel, long val)
	{
	struct lm83_data *data = dev_get_drvdata(dev);
	unsigned int regval;
	int err;

	switch (attr) {
	case hwmon_temp_input:
	err = regmap_read(data->regmap, LM83_REG_TEMP[channel], &regval);
	if (err < 0)
	return err;
	val = (s8)regval 1000;
	break;
	case hwmon_temp_max:
	err = regmap_read(data->regmap, LM83_REG_MAX[channel], &regval);
	if (err < 0)
	return err;
	val = (s8)regval 1000;
	break;
	case hwmon_temp_crit:
	err = regmap_read(data->regmap, LM83_REG_R_TCRIT, &regval);
	if (err < 0)
	return err;
	val = (s8)regval 1000;
	break;
	case hwmon_temp_max_alarm:
	err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
	if (err < 0)
	return err;
	*val = !!(regval & LM83_MAX_ALARM_BIT[channel]);
	break;
	case hwmon_temp_crit_alarm:
	err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
	if (err < 0)
	return err;
	*val = !!(regval & LM83_CRIT_ALARM_BIT[channel]);
	break;
	case hwmon_temp_fault:
	err = regmap_read(data->regmap, LM83_ALARM_REG[channel], &regval);
	if (err < 0)
	return err;
	*val = !!(regval & LM83_FAULT_BIT[channel]);
	break;
	default:
	return -EOPNOTSUPP;
	}
	return 0;
	}

	static int lm83_temp_write(struct device *dev, u32 attr, int channel, long val)
	{
	struct lm83_data *data = dev_get_drvdata(dev);
	unsigned int regval;
	int err;

	regval = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);

	switch (attr) {
	case hwmon_temp_max:
	err = regmap_write(data->regmap, LM83_REG_MAX[channel], regval);
	if (err < 0)
	return err;
	break;
	case hwmon_temp_crit:
	err = regmap_write(data->regmap, LM83_REG_R_TCRIT, regval);
	if (err < 0)
	return err;
	break;
	default:
	return -EOPNOTSUPP;
	}
	return 0;
	}

	static int lm83_chip_read(struct device dev, u32 attr, int channel, long val)
	{
	struct lm83_data *data = dev_get_drvdata(dev);
	unsigned int regval;
	int err;

	switch (attr) {
	case hwmon_chip_alarms:
	err = regmap_read(data->regmap, LM83_REG_R_STATUS1, &regval);
	if (err < 0)
	return err;
	*val = regval;
	err = regmap_read(data->regmap, LM83_REG_R_STATUS2, &regval);
	if (err < 0)
	return err;
	*val \|= regval << 8;
	return 0;
	default:
	return -EOPNOTSUPP;
	}

	return 0;
	}

	static int lm83_read(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long *val)
	{
	switch (type) {
	case hwmon_chip:
	return lm83_chip_read(dev, attr, channel, val);
	case hwmon_temp:
	return lm83_temp_read(dev, attr, channel, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static int lm83_write(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long val)
	{
	switch (type) {
	case hwmon_temp:
	return lm83_temp_write(dev, attr, channel, val);
	default:
	return -EOPNOTSUPP;
	}
	}

	static umode_t lm83_is_visible(const void *_data, enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	const struct lm83_data *data = _data;

	/*
	* LM82 only supports a single external channel, modeled as channel 2.
	*/
	if (data->type == lm82 && (channel == 1 \|\| channel == 3))
	return 0;

	switch (type) {
	case hwmon_chip:
	if (attr == hwmon_chip_alarms)
	return 0444;
	break;
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_input:
	case hwmon_temp_max_alarm:
	case hwmon_temp_crit_alarm:
	return 0444;
	case hwmon_temp_fault:
	if (channel)
	return 0444;
	break;
	case hwmon_temp_max:
	return 0644;
	case hwmon_temp_crit:
	if (channel == 2)
	return 0644;
	return 0444;
	default:
	break;
	}
	break;
	default:
	break;
	}
	return 0;
	}

	static const struct hwmon_channel_info * const lm83_info[] = {
	HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
	HWMON_CHANNEL_INFO(temp,
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_CRIT \|
	HWMON_T_MAX_ALARM \| HWMON_T_CRIT_ALARM,
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_CRIT \|
	HWMON_T_MAX_ALARM \| HWMON_T_CRIT_ALARM \| HWMON_T_FAULT,
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_CRIT \|
	HWMON_T_MAX_ALARM \| HWMON_T_CRIT_ALARM \| HWMON_T_FAULT,
	HWMON_T_INPUT \| HWMON_T_MAX \| HWMON_T_CRIT \|
	HWMON_T_MAX_ALARM \| HWMON_T_CRIT_ALARM \| HWMON_T_FAULT
	),
	NULL
	};

	static const struct hwmon_ops lm83_hwmon_ops = {
	.is_visible = lm83_is_visible,
	.read = lm83_read,
	.write = lm83_write,
	};

	static const struct hwmon_chip_info lm83_chip_info = {
	.ops = &lm83_hwmon_ops,
	.info = lm83_info,
	};

	/* Return 0 if detection is successful, -ENODEV otherwise */
	static int lm83_detect(struct i2c_client *client,
	struct i2c_board_info *info)
	{
	struct i2c_adapter *adapter = client->adapter;
	const char *name;
	u8 man_id, chip_id;

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

	/* Detection */
	if ((i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS1) & 0xA8) \|\|
	(i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS2) & 0x48) \|\|
	(i2c_smbus_read_byte_data(client, LM83_REG_R_CONFIG) & 0x41)) {
	dev_dbg(&adapter->dev, "LM83 detection failed at 0x%02x\n",
	client->addr);
	return -ENODEV;
	}

	/* Identification */
	man_id = i2c_smbus_read_byte_data(client, LM83_REG_R_MAN_ID);
	if (man_id != 0x01) /* National Semiconductor */
	return -ENODEV;

	chip_id = i2c_smbus_read_byte_data(client, LM83_REG_R_CHIP_ID);
	switch (chip_id) {
	case 0x03:
	/*
	* According to the LM82 datasheet dated March 2013, recent
	* revisions of LM82 have a die revision of 0x03. This was
	* confirmed with a real chip. Further details in this revision
	* of the LM82 datasheet strongly suggest that LM82 is just a
	* repackaged LM83. It is therefore impossible to distinguish
	* those chips from LM83, and they will be misdetected as LM83.
	*/
	name = "lm83";
	break;
	case 0x01:
	name = "lm82";
	break;
	default:
	/* identification failed */
	dev_dbg(&adapter->dev,
	"Unsupported chip (man_id=0x%02X, chip_id=0x%02X)\n",
	man_id, chip_id);
	return -ENODEV;
	}

	strscpy(info->type, name, I2C_NAME_SIZE);

	return 0;
	}

	static const struct i2c_device_id lm83_id[] = {
	{ "lm83", lm83 },
	{ "lm82", lm82 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, lm83_id);

	static int lm83_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct lm83_data *data;

	data = devm_kzalloc(dev, sizeof(struct lm83_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->regmap = devm_regmap_init(dev, NULL, client, &lm83_regmap_config);
	if (IS_ERR(data->regmap))
	return PTR_ERR(data->regmap);

	data->type = i2c_match_id(lm83_id, client)->driver_data;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
	data, &lm83_chip_info, NULL);
	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	/*
	* Driver data (common to all clients)
	*/

	static struct i2c_driver lm83_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
	.name = "lm83",
	},
	.probe_new = lm83_probe,
	.id_table = lm83_id,
	.detect = lm83_detect,
	.address_list = normal_i2c,
	};

	module_i2c_driver(lm83_driver);

	MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
	MODULE_DESCRIPTION("LM83 driver");
	MODULE_LICENSE("GPL");