// SPDX-License-Identifier: GPL-2.0-or-later

  /* tmp421.c
   *
   * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
   * Preliminary support by:
   * Melvin Rook, Raymond Ng

   */
  
  /*
   * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.

   * Supported models: TMP421, TMP422, TMP423, TMP441, TMP442

   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>

  #include <linux/of_device.h>

  #include <linux/sysfs.h>
  
  /* Addresses to scan */

  static const unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
  					     I2C_CLIENT_END };

  enum chips { tmp421, tmp422, tmp423, tmp441, tmp442 };

  
  /* The TMP421 registers */

  #define TMP421_STATUS_REG			0x08

  #define TMP421_CONFIG_REG_1			0x09
  #define TMP421_CONVERSION_RATE_REG		0x0B
  #define TMP421_MANUFACTURER_ID_REG		0xFE
  #define TMP421_DEVICE_ID_REG			0xFF
  
  static const u8 TMP421_TEMP_MSB[4]		= { 0x00, 0x01, 0x02, 0x03 };
  static const u8 TMP421_TEMP_LSB[4]		= { 0x10, 0x11, 0x12, 0x13 };
  
  /* Flags */
  #define TMP421_CONFIG_SHUTDOWN			0x40
  #define TMP421_CONFIG_RANGE			0x04
  
  /* Manufacturer / Device ID's */
  #define TMP421_MANUFACTURER_ID			0x55
  #define TMP421_DEVICE_ID			0x21
  #define TMP422_DEVICE_ID			0x22
  #define TMP423_DEVICE_ID			0x23

  #define TMP441_DEVICE_ID			0x41
  #define TMP442_DEVICE_ID			0x42

  
  static const struct i2c_device_id tmp421_id[] = {

  	{ "tmp421", 2 },
  	{ "tmp422", 3 },
  	{ "tmp423", 4 },

  	{ "tmp441", 2 },
  	{ "tmp442", 3 },

  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, tmp421_id);

  static const struct of_device_id __maybe_unused tmp421_of_match[] = {

  	{
  		.compatible = "ti,tmp421",
  		.data = (void *)2
  	},
  	{
  		.compatible = "ti,tmp422",
  		.data = (void *)3
  	},
  	{
  		.compatible = "ti,tmp423",
  		.data = (void *)4
  	},
  	{
  		.compatible = "ti,tmp441",
  		.data = (void *)2
  	},
  	{

  		.compatible = "ti,tmp442",

  		.data = (void *)3
  	},
  	{ },
  };
  MODULE_DEVICE_TABLE(of, tmp421_of_match);

  struct tmp421_data {

  	struct i2c_client *client;

  	struct mutex update_lock;

  	u32 temp_config[5];
  	struct hwmon_channel_info temp_info;
  	const struct hwmon_channel_info *info[2];
  	struct hwmon_chip_info chip;

  	char valid;
  	unsigned long last_updated;

  	unsigned long channels;

  	u8 config;
  	s16 temp[4];
  };
  
  static int temp_from_s16(s16 reg)
  {

  	/* Mask out status bits */
  	int temp = reg & ~0xf;

  
  	return (temp * 1000 + 128) / 256;
  }
  
  static int temp_from_u16(u16 reg)
  {

  	/* Mask out status bits */
  	int temp = reg & ~0xf;

  
  	/* Add offset for extended temperature range. */
  	temp -= 64 * 256;
  
  	return (temp * 1000 + 128) / 256;
  }
  
  static struct tmp421_data *tmp421_update_device(struct device *dev)
  {

  	struct tmp421_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  	int i;
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
  		data->config = i2c_smbus_read_byte_data(client,
  			TMP421_CONFIG_REG_1);

  		for (i = 0; i < data->channels; i++) {

  			data->temp[i] = i2c_smbus_read_byte_data(client,
  				TMP421_TEMP_MSB[i]) << 8;
  			data->temp[i] |= i2c_smbus_read_byte_data(client,
  				TMP421_TEMP_LSB[i]);
  		}
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return data;
  }

  static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
  		       u32 attr, int channel, long *val)

  {

  	struct tmp421_data *tmp421 = tmp421_update_device(dev);
  
  	switch (attr) {
  	case hwmon_temp_input:
  		if (tmp421->config & TMP421_CONFIG_RANGE)
  			*val = temp_from_u16(tmp421->temp[channel]);
  		else
  			*val = temp_from_s16(tmp421->temp[channel]);
  		return 0;
  	case hwmon_temp_fault:
  		/*
  		 * The OPEN bit signals a fault. This is bit 0 of the temperature
  		 * register (low byte).
  		 */
  		*val = tmp421->temp[channel] & 0x01;
  		return 0;
  	default:
  		return -EOPNOTSUPP;
  	}

  }

  static umode_t tmp421_is_visible(const void *data, enum hwmon_sensor_types type,
  				 u32 attr, int channel)

  {

  	switch (attr) {
  	case hwmon_temp_fault:
  		if (channel == 0)
  			return 0;

  		return 0444;

  	case hwmon_temp_input:

  		return 0444;

  	default:
  		return 0;
  	}

  }

  static int tmp421_init_client(struct i2c_client *client)
  {
  	int config, config_orig;
  
  	/* Set the conversion rate to 2 Hz */
  	i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);
  
  	/* Start conversions (disable shutdown if necessary) */
  	config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
  	if (config < 0) {

  		dev_err(&client->dev,
  			"Could not read configuration register (%d)
  ", config);

  		return config;

  	}
  
  	config_orig = config;
  	config &= ~TMP421_CONFIG_SHUTDOWN;
  
  	if (config != config_orig) {
  		dev_info(&client->dev, "Enable monitoring chip
  ");
  		i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
  	}
  
  	return 0;
  }

  static int tmp421_detect(struct i2c_client *client,

  			 struct i2c_board_info *info)
  {

  	enum chips kind;

  	struct i2c_adapter *adapter = client->adapter;

  	static const char * const names[] = {
  		"TMP421", "TMP422", "TMP423",
  		"TMP441", "TMP442"
  	};

  	int addr = client->addr;

  	u8 reg;

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

  	reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
  	if (reg != TMP421_MANUFACTURER_ID)
  		return -ENODEV;

  	reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
  	if (reg & 0xf8)
  		return -ENODEV;
  
  	reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
  	if (reg & 0x7f)
  		return -ENODEV;

  	reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
  	switch (reg) {
  	case TMP421_DEVICE_ID:
  		kind = tmp421;
  		break;
  	case TMP422_DEVICE_ID:

  		if (addr == 0x2a)
  			return -ENODEV;

  		kind = tmp422;
  		break;
  	case TMP423_DEVICE_ID:

  		if (addr != 0x4c && addr != 0x4d)
  			return -ENODEV;

  		kind = tmp423;
  		break;

  	case TMP441_DEVICE_ID:
  		kind = tmp441;
  		break;
  	case TMP442_DEVICE_ID:
  		if (addr != 0x4c && addr != 0x4d)
  			return -ENODEV;
  		kind = tmp442;
  		break;

  	default:
  		return -ENODEV;

  	}

  	strlcpy(info->type, tmp421_id[kind].name, I2C_NAME_SIZE);

  	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x
  ",

  		 names[kind], client->addr);

  
  	return 0;
  }

  static const struct hwmon_ops tmp421_ops = {
  	.is_visible = tmp421_is_visible,
  	.read = tmp421_read,
  };

  static int tmp421_probe(struct i2c_client *client,
  			const struct i2c_device_id *id)
  {

  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;

  	struct tmp421_data *data;

  	int i, err;

  	data = devm_kzalloc(dev, sizeof(struct tmp421_data), GFP_KERNEL);

  	if (!data)
  		return -ENOMEM;

  	mutex_init(&data->update_lock);

  	if (client->dev.of_node)
  		data->channels = (unsigned long)
  			of_device_get_match_data(&client->dev);
  	else
  		data->channels = id->driver_data;

  	data->client = client;

  
  	err = tmp421_init_client(client);
  	if (err)

  		return err;

  	for (i = 0; i < data->channels; i++)
  		data->temp_config[i] = HWMON_T_INPUT | HWMON_T_FAULT;
  
  	data->chip.ops = &tmp421_ops;
  	data->chip.info = data->info;
  
  	data->info[0] = &data->temp_info;
  
  	data->temp_info.type = hwmon_temp;
  	data->temp_info.config = data->temp_config;
  
  	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
  							 data,
  							 &data->chip,
  							 NULL);

  	return PTR_ERR_OR_ZERO(hwmon_dev);

  }
  
  static struct i2c_driver tmp421_driver = {
  	.class = I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "tmp421",

  		.of_match_table = of_match_ptr(tmp421_of_match),

  	},
  	.probe = tmp421_probe,

  	.id_table = tmp421_id,
  	.detect = tmp421_detect,

  	.address_list = normal_i2c,

  };

  module_i2c_driver(tmp421_driver);

  
  MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");

  MODULE_DESCRIPTION("Texas Instruments TMP421/422/423/441/442 temperature sensor driver");

  MODULE_LICENSE("GPL");