// 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/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>

  #include <linux/hwmon-sysfs.h>

  #include <linux/hwmon.h>
  #include <linux/err.h>

  #include <linux/mutex.h>

  #include <linux/sysfs.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
  
  /*
   * Conversions and various macros

   * The LM83 uses signed 8-bit values with LSB = 1 degree Celsius.

   */
  
  #define TEMP_FROM_REG(val)	((val) * 1000)
  #define TEMP_TO_REG(val)	((val) <= -128000 ? -128 : \
  				 (val) >= 127000 ? 127 : \
  				 (val) < 0 ? ((val) - 500) / 1000 : \
  				 ((val) + 500) / 1000)
  
  static const u8 LM83_REG_R_TEMP[] = {
  	LM83_REG_R_LOCAL_TEMP,
  	LM83_REG_R_REMOTE1_TEMP,
  	LM83_REG_R_REMOTE2_TEMP,

  	LM83_REG_R_REMOTE3_TEMP,

  	LM83_REG_R_LOCAL_HIGH,
  	LM83_REG_R_REMOTE1_HIGH,
  	LM83_REG_R_REMOTE2_HIGH,

  	LM83_REG_R_REMOTE3_HIGH,
  	LM83_REG_R_TCRIT,

  };
  
  static const u8 LM83_REG_W_HIGH[] = {
  	LM83_REG_W_LOCAL_HIGH,
  	LM83_REG_W_REMOTE1_HIGH,
  	LM83_REG_W_REMOTE2_HIGH,

  	LM83_REG_W_REMOTE3_HIGH,
  	LM83_REG_W_TCRIT,

  };
  
  /*

   * Client data (each client gets its own)
   */
  
  struct lm83_data {

  	struct i2c_client *client;
  	const struct attribute_group *groups[3];

  	struct mutex update_lock;

  	char valid; /* zero until following fields are valid */
  	unsigned long last_updated; /* in jiffies */
  
  	/* registers values */

  	s8 temp[9];	/* 0..3: input 1-4,
  			   4..7: high limit 1-4,
  			   8   : critical limit */

  	u16 alarms; /* bitvector, combined */
  };

  static struct lm83_data *lm83_update_device(struct device *dev)
  {

  	struct lm83_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
  		int nr;
  
  		dev_dbg(&client->dev, "Updating lm83 data.
  ");
  		for (nr = 0; nr < 9; nr++) {
  			data->temp[nr] =
  			    i2c_smbus_read_byte_data(client,
  			    LM83_REG_R_TEMP[nr]);
  		}
  		data->alarms =
  		    i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS1)
  		    + (i2c_smbus_read_byte_data(client, LM83_REG_R_STATUS2)
  		    << 8);
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return data;
  }

  /*
   * Sysfs stuff
   */

  static ssize_t temp_show(struct device *dev, struct device_attribute *devattr,

  			 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm83_data *data = lm83_update_device(dev);
  	return sprintf(buf, "%d
  ", TEMP_FROM_REG(data->temp[attr->index]));

  }

  static ssize_t temp_store(struct device *dev,
  			  struct device_attribute *devattr, const char *buf,
  			  size_t count)

  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);

  	struct lm83_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  	long val;

  	int nr = attr->index;

  	int err;
  
  	err = kstrtol(buf, 10, &val);
  	if (err < 0)
  		return err;

  	mutex_lock(&data->update_lock);

  	data->temp[nr] = TEMP_TO_REG(val);
  	i2c_smbus_write_byte_data(client, LM83_REG_W_HIGH[nr - 4],
  				  data->temp[nr]);

  	mutex_unlock(&data->update_lock);

  	return count;

  }

  static ssize_t alarms_show(struct device *dev, struct device_attribute *dummy,

  			   char *buf)

  {
  	struct lm83_data *data = lm83_update_device(dev);
  	return sprintf(buf, "%d
  ", data->alarms);
  }

  static ssize_t alarm_show(struct device *dev,
  			  struct device_attribute *devattr, char *buf)

  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct lm83_data *data = lm83_update_device(dev);
  	int bitnr = attr->index;
  
  	return sprintf(buf, "%d
  ", (data->alarms >> bitnr) & 1);
  }

  static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
  static SENSOR_DEVICE_ATTR_RO(temp2_input, temp, 1);
  static SENSOR_DEVICE_ATTR_RO(temp3_input, temp, 2);
  static SENSOR_DEVICE_ATTR_RO(temp4_input, temp, 3);
  static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 4);
  static SENSOR_DEVICE_ATTR_RW(temp2_max, temp, 5);
  static SENSOR_DEVICE_ATTR_RW(temp3_max, temp, 6);
  static SENSOR_DEVICE_ATTR_RW(temp4_max, temp, 7);
  static SENSOR_DEVICE_ATTR_RO(temp1_crit, temp, 8);
  static SENSOR_DEVICE_ATTR_RO(temp2_crit, temp, 8);
  static SENSOR_DEVICE_ATTR_RW(temp3_crit, temp, 8);
  static SENSOR_DEVICE_ATTR_RO(temp4_crit, temp, 8);

  
  /* Individual alarm files */

  static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, alarm, 0);
  static SENSOR_DEVICE_ATTR_RO(temp3_crit_alarm, alarm, 1);
  static SENSOR_DEVICE_ATTR_RO(temp3_fault, alarm, 2);
  static SENSOR_DEVICE_ATTR_RO(temp3_max_alarm, alarm, 4);
  static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, 6);
  static SENSOR_DEVICE_ATTR_RO(temp2_crit_alarm, alarm, 8);
  static SENSOR_DEVICE_ATTR_RO(temp4_crit_alarm, alarm, 9);
  static SENSOR_DEVICE_ATTR_RO(temp4_fault, alarm, 10);
  static SENSOR_DEVICE_ATTR_RO(temp4_max_alarm, alarm, 12);
  static SENSOR_DEVICE_ATTR_RO(temp2_fault, alarm, 13);
  static SENSOR_DEVICE_ATTR_RO(temp2_max_alarm, alarm, 15);

  /* Raw alarm file for compatibility */

  static DEVICE_ATTR_RO(alarms);

  static struct attribute *lm83_attributes[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit.dev_attr.attr,
  
  	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_crit_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp3_fault.dev_attr.attr,

  	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&dev_attr_alarms.attr,
  	NULL
  };
  
  static const struct attribute_group lm83_group = {
  	.attrs = lm83_attributes,
  };
  
  static struct attribute *lm83_attributes_opt[] = {
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp4_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp4_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
  	&sensor_dev_attr_temp4_crit.dev_attr.attr,
  
  	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp4_crit_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp4_fault.dev_attr.attr,

  	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,

  	&sensor_dev_attr_temp2_fault.dev_attr.attr,

  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group lm83_group_opt = {
  	.attrs = lm83_attributes_opt,
  };

  /*
   * Real code
   */

  /* Return 0 if detection is successful, -ENODEV otherwise */

  static int lm83_detect(struct i2c_client *new_client,

  		       struct i2c_board_info *info)

  {

  	struct i2c_adapter *adapter = new_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(new_client, LM83_REG_R_STATUS1) & 0xA8) ||
  	    (i2c_smbus_read_byte_data(new_client, LM83_REG_R_STATUS2) & 0x48) ||
  	    (i2c_smbus_read_byte_data(new_client, LM83_REG_R_CONFIG) & 0x41)) {
  		dev_dbg(&adapter->dev, "LM83 detection failed at 0x%02x
  ",
  			new_client->addr);
  		return -ENODEV;

  	}

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

  	chip_id = i2c_smbus_read_byte_data(new_client, LM83_REG_R_CHIP_ID);
  	switch (chip_id) {
  	case 0x03:

  		name = "lm83";

  		break;
  	case 0x01:

  		name = "lm82";

  		break;
  	default:
  		/* identification failed */
  		dev_info(&adapter->dev,
  			 "Unsupported chip (man_id=0x%02X, chip_id=0x%02X)
  ",
  			 man_id, chip_id);
  		return -ENODEV;

  	}

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

  static const struct i2c_device_id lm83_id[];
  
  static int lm83_probe(struct i2c_client *new_client)

  {

  	struct device *hwmon_dev;

  	struct lm83_data *data;

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

  	data->client = new_client;

  	mutex_init(&data->update_lock);

  	/*

  	 * Register sysfs hooks

  	 * The LM82 can only monitor one external diode which is
  	 * at the same register as the LM83 temp3 entry - so we
  	 * declare 1 and 3 common, and then 2 and 4 only for the LM83.
  	 */

  	data->groups[0] = &lm83_group;

  	if (i2c_match_id(lm83_id, new_client)->driver_data == lm83)

  		data->groups[1] = &lm83_group_opt;
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
  							   new_client->name,
  							   data, data->groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);

  }

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

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

  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");