text: /* Texas Instruments TMP102 SMBus temperature sensor driver
   *
   * Copyright (C) 2010 Steven King <sfking@fdwdc.com>
   *
   * 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/delay.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <linux/device.h>
  #include <linux/jiffies.h>
  #include <linux/regmap.h>
  #include <linux/of.h>
  
  #define	DRIVER_NAME "tmp102"
  
  #define	TMP102_TEMP_REG			0x00
  #define	TMP102_CONF_REG			0x01
  /* note: these bit definitions are byte swapped */
  #define		TMP102_CONF_SD		0x0100
  #define		TMP102_CONF_TM		0x0200
  #define		TMP102_CONF_POL		0x0400
  #define		TMP102_CONF_F0		0x0800
  #define		TMP102_CONF_F1		0x1000
  #define		TMP102_CONF_R0		0x2000
  #define		TMP102_CONF_R1		0x4000
  #define		TMP102_CONF_OS		0x8000
  #define		TMP102_CONF_EM		0x0010
  #define		TMP102_CONF_AL		0x0020
  #define		TMP102_CONF_CR0		0x0040
  #define		TMP102_CONF_CR1		0x0080
  #define	TMP102_TLOW_REG			0x02
  #define	TMP102_THIGH_REG		0x03
  
  #define TMP102_CONFREG_MASK	(TMP102_CONF_SD | TMP102_CONF_TM | \
  				 TMP102_CONF_POL | TMP102_CONF_F0 | \
  				 TMP102_CONF_F1 | TMP102_CONF_OS | \
  				 TMP102_CONF_EM | TMP102_CONF_AL | \
  				 TMP102_CONF_CR0 | TMP102_CONF_CR1)
  
  #define TMP102_CONFIG_CLEAR	(TMP102_CONF_SD | TMP102_CONF_OS | \
  				 TMP102_CONF_CR0)
  #define TMP102_CONFIG_SET	(TMP102_CONF_TM | TMP102_CONF_EM | \
  				 TMP102_CONF_CR1)
  
  #define CONVERSION_TIME_MS		35	/* in milli-seconds */
  
  struct tmp102 {
  	struct regmap *regmap;
  	u16 config_orig;
  	unsigned long ready_time;
  };
  
  /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
  static inline int tmp102_reg_to_mC(s16 val)
  {
  	return ((val & ~0x01) * 1000) / 128;
  }
  
  /* convert milliCelsius to left adjusted 13-bit TMP102 register value */
  static inline u16 tmp102_mC_to_reg(int val)
  {
  	return (val * 128) / 1000;
  }
  
  static int tmp102_read(struct device *dev, enum hwmon_sensor_types type,
  		       u32 attr, int channel, long *temp)
  {
  	struct tmp102 *tmp102 = dev_get_drvdata(dev);
  	unsigned int regval;
  	int err, reg;
  
  	switch (attr) {
  	case hwmon_temp_input:
  		/* Is it too early to return a conversion ? */
  		if (time_before(jiffies, tmp102->ready_time)) {
  			dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
  			return -EAGAIN;
  		}
  		reg = TMP102_TEMP_REG;
  		break;
  	case hwmon_temp_max_hyst:
  		reg = TMP102_TLOW_REG;
  		break;
  	case hwmon_temp_max:
  		reg = TMP102_THIGH_REG;
  		break;
  	default:
  		return -EOPNOTSUPP;
  	}
  
  	err = regmap_read(tmp102->regmap, reg, &regval);
  	if (err < 0)
  		return err;
  	*temp = tmp102_reg_to_mC(regval);
  
  	return 0;
  }
  
  static int tmp102_write(struct device *dev, enum hwmon_sensor_types type,
  			u32 attr, int channel, long temp)
  {
  	struct tmp102 *tmp102 = dev_get_drvdata(dev);
  	int reg;
  
  	switch (attr) {
  	case hwmon_temp_max_hyst:
  		reg = TMP102_TLOW_REG;
  		break;
  	case hwmon_temp_max:
  		reg = TMP102_THIGH_REG;
  		break;
  	default:
  		return -EOPNOTSUPP;
  	}
  
  	temp = clamp_val(temp, -256000, 255000);
  	return regmap_write(tmp102->regmap, reg, tmp102_mC_to_reg(temp));
  }
  
  static umode_t tmp102_is_visible(const void *data, enum hwmon_sensor_types type,
  				 u32 attr, int channel)
  {
  	if (type != hwmon_temp)
  		return 0;
  
  	switch (attr) {
  	case hwmon_temp_input:
  		return 0444;
  	case hwmon_temp_max_hyst:
  	case hwmon_temp_max:
  		return 0644;
  	default:
  		return 0;
  	}
  }
  
  static u32 tmp102_chip_config[] = {
  	HWMON_C_REGISTER_TZ,
  	0
  };
  
  static const struct hwmon_channel_info tmp102_chip = {
  	.type = hwmon_chip,
  	.config = tmp102_chip_config,
  };
  
  static u32 tmp102_temp_config[] = {
  	HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
  	0
  };
  
  static const struct hwmon_channel_info tmp102_temp = {
  	.type = hwmon_temp,
  	.config = tmp102_temp_config,
  };
  
  static const struct hwmon_channel_info *tmp102_info[] = {
  	&tmp102_chip,
  	&tmp102_temp,
  	NULL
  };
  
  static const struct hwmon_ops tmp102_hwmon_ops = {
  	.is_visible = tmp102_is_visible,
  	.read = tmp102_read,
  	.write = tmp102_write,
  };
  
  static const struct hwmon_chip_info tmp102_chip_info = {
  	.ops = &tmp102_hwmon_ops,
  	.info = tmp102_info,
  };
  
  static void tmp102_restore_config(void *data)
  {
  	struct tmp102 *tmp102 = data;
  
  	regmap_write(tmp102->regmap, TMP102_CONF_REG, tmp102->config_orig);
  }
  
  static bool tmp102_is_writeable_reg(struct device *dev, unsigned int reg)
  {
  	return reg != TMP102_TEMP_REG;
  }
  
  static bool tmp102_is_volatile_reg(struct device *dev, unsigned int reg)
  {
  	return reg == TMP102_TEMP_REG;
  }
  
  static const struct regmap_config tmp102_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 16,
  	.max_register = TMP102_THIGH_REG,
  	.writeable_reg = tmp102_is_writeable_reg,
  	.volatile_reg = tmp102_is_volatile_reg,
  	.val_format_endian = REGMAP_ENDIAN_BIG,
  	.cache_type = REGCACHE_RBTREE,
  	.use_single_read = true,
  	.use_single_write = true,
  };
  
  static int tmp102_probe(struct i2c_client *client,
  			const struct i2c_device_id *id)
  {
  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;
  	struct tmp102 *tmp102;
  	unsigned int regval;
  	int err;
  
  	if (!i2c_check_functionality(client->adapter,
  				     I2C_FUNC_SMBUS_WORD_DATA)) {
  		dev_err(dev,
  			"adapter doesn't support SMBus word transactions\n");
  		return -ENODEV;
  	}
  
  	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
  	if (!tmp102)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, tmp102);
  
  	tmp102->regmap = devm_regmap_init_i2c(client, &tmp102_regmap_config);
  	if (IS_ERR(tmp102->regmap))
  		return PTR_ERR(tmp102->regmap);
  
  	err = regmap_read(tmp102->regmap, TMP102_CONF_REG, &regval);
  	if (err < 0) {
  		dev_err(dev, "error reading config register\n");
  		return err;
  	}
  
  	if ((regval & ~TMP102_CONFREG_MASK) !=
  	    (TMP102_CONF_R0 | TMP102_CONF_R1)) {
  		dev_err(dev, "unexpected config register value\n");
  		return -ENODEV;
  	}
  
  	tmp102->config_orig = regval;
  
  	err = devm_add_action_or_reset(dev, tmp102_restore_config, tmp102);
  	if (err)
  		return err;
  
  	regval &= ~TMP102_CONFIG_CLEAR;
  	regval |= TMP102_CONFIG_SET;
  
  	err = regmap_write(tmp102->regmap, TMP102_CONF_REG, regval);
  	if (err < 0) {
  		dev_err(dev, "error writing config register\n");
  		return err;
  	}
  
  	/*
  	 * Mark that we are not ready with data until the first
  	 * conversion is complete
  	 */
  	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
  
  	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
  							 tmp102,
  							 &tmp102_chip_info,
  							 NULL);
  	if (IS_ERR(hwmon_dev)) {
  		dev_dbg(dev, "unable to register hwmon device\n");
  		return PTR_ERR(hwmon_dev);
  	}
  	dev_info(dev, "initialized\n");
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int tmp102_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct tmp102 *tmp102 = i2c_get_clientdata(client);
  
  	return regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
  				  TMP102_CONF_SD, TMP102_CONF_SD);
  }
  
  static int tmp102_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct tmp102 *tmp102 = i2c_get_clientdata(client);
  	int err;
  
  	err = regmap_update_bits(tmp102->regmap, TMP102_CONF_REG,
  				 TMP102_CONF_SD, 0);
  
  	tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS);
  
  	return err;
  }
  #endif /* CONFIG_PM */
  
  static SIMPLE_DEV_PM_OPS(tmp102_dev_pm_ops, tmp102_suspend, tmp102_resume);
  
  static const struct i2c_device_id tmp102_id[] = {
  	{ "tmp102", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, tmp102_id);
  
  static const struct of_device_id tmp102_of_match[] = {
  	{ .compatible = "ti,tmp102" },
  	{ },
  };
  MODULE_DEVICE_TABLE(of, tmp102_of_match);
  
  static struct i2c_driver tmp102_driver = {
  	.driver.name	= DRIVER_NAME,
  	.driver.of_match_table = of_match_ptr(tmp102_of_match),
  	.driver.pm	= &tmp102_dev_pm_ops,
  	.probe		= tmp102_probe,
  	.id_table	= tmp102_id,
  };
  
  module_i2c_driver(tmp102_driver);
  
  MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
  MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
  MODULE_LICENSE("GPL");
  