/* 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
   */

  #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>

  
  #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
  
  struct tmp102 {
  	struct device *hwmon_dev;
  	struct mutex lock;

  	u16 config_orig;

  	unsigned long last_update;
  	int temp[3];
  };

  /* 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 const u8 tmp102_reg[] = {
  	TMP102_TEMP_REG,
  	TMP102_TLOW_REG,
  	TMP102_THIGH_REG,
  };
  
  static struct tmp102 *tmp102_update_device(struct i2c_client *client)
  {
  	struct tmp102 *tmp102 = i2c_get_clientdata(client);
  
  	mutex_lock(&tmp102->lock);

  	if (time_after(jiffies, tmp102->last_update + HZ / 3)) {

  		int i;
  		for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {

  			int status = i2c_smbus_read_word_swapped(client,
  								 tmp102_reg[i]);

  			if (status > -1)
  				tmp102->temp[i] = tmp102_reg_to_mC(status);
  		}
  		tmp102->last_update = jiffies;
  	}
  	mutex_unlock(&tmp102->lock);
  	return tmp102;
  }
  
  static ssize_t tmp102_show_temp(struct device *dev,
  				struct device_attribute *attr,
  				char *buf)
  {
  	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
  	struct tmp102 *tmp102 = tmp102_update_device(to_i2c_client(dev));
  
  	return sprintf(buf, "%d
  ", tmp102->temp[sda->index]);
  }
  
  static ssize_t tmp102_set_temp(struct device *dev,
  			       struct device_attribute *attr,
  			       const char *buf, size_t count)
  {
  	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
  	struct i2c_client *client = to_i2c_client(dev);
  	struct tmp102 *tmp102 = i2c_get_clientdata(client);
  	long val;

  	int status;

  	if (kstrtol(buf, 10, &val) < 0)

  		return -EINVAL;

  	val = SENSORS_LIMIT(val, -256000, 255000);

  	mutex_lock(&tmp102->lock);

  	tmp102->temp[sda->index] = val;

  	status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
  					      tmp102_mC_to_reg(val));

  	mutex_unlock(&tmp102->lock);
  	return status ? : count;
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);
  
  static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
  			  tmp102_set_temp, 1);
  
  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
  			  tmp102_set_temp, 2);
  
  static struct attribute *tmp102_attributes[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group tmp102_attr_group = {
  	.attrs = tmp102_attributes,
  };
  
  #define TMP102_CONFIG  (TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
  #define TMP102_CONFIG_RD_ONLY (TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)
  
  static int __devinit tmp102_probe(struct i2c_client *client,
  				  const struct i2c_device_id *id)
  {
  	struct tmp102 *tmp102;
  	int status;

  	if (!i2c_check_functionality(client->adapter,

  				     I2C_FUNC_SMBUS_WORD_DATA)) {

  		dev_err(&client->dev, "adapter doesn't support SMBus word "

  			"transactions
  ");

  		return -ENODEV;
  	}
  
  	tmp102 = kzalloc(sizeof(*tmp102), GFP_KERNEL);
  	if (!tmp102) {
  		dev_dbg(&client->dev, "kzalloc failed
  ");
  		return -ENOMEM;
  	}
  	i2c_set_clientdata(client, tmp102);

  	status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);

  	if (status < 0) {
  		dev_err(&client->dev, "error reading config register
  ");
  		goto fail_free;
  	}
  	tmp102->config_orig = status;

  	status = i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
  					      TMP102_CONFIG);

  	if (status < 0) {
  		dev_err(&client->dev, "error writing config register
  ");

  		goto fail_restore_config;

  	}

  	status = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);

  	if (status < 0) {

  		dev_err(&client->dev, "error reading config register
  ");

  		goto fail_restore_config;

  	}
  	status &= ~TMP102_CONFIG_RD_ONLY;
  	if (status != TMP102_CONFIG) {

  		dev_err(&client->dev, "config settings did not stick
  ");
  		status = -ENODEV;

  		goto fail_restore_config;

  	}
  	tmp102->last_update = jiffies - HZ;
  	mutex_init(&tmp102->lock);
  
  	status = sysfs_create_group(&client->dev.kobj, &tmp102_attr_group);
  	if (status) {
  		dev_dbg(&client->dev, "could not create sysfs files
  ");

  		goto fail_restore_config;

  	}
  	tmp102->hwmon_dev = hwmon_device_register(&client->dev);
  	if (IS_ERR(tmp102->hwmon_dev)) {
  		dev_dbg(&client->dev, "unable to register hwmon device
  ");
  		status = PTR_ERR(tmp102->hwmon_dev);

  		goto fail_remove_sysfs;

  	}
  
  	dev_info(&client->dev, "initialized
  ");
  
  	return 0;

  
  fail_remove_sysfs:

  	sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);

  fail_restore_config:

  	i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
  				     tmp102->config_orig);

  fail_free:

  	kfree(tmp102);

  	return status;

  }
  
  static int __devexit tmp102_remove(struct i2c_client *client)
  {
  	struct tmp102 *tmp102 = i2c_get_clientdata(client);

  	hwmon_device_unregister(tmp102->hwmon_dev);
  	sysfs_remove_group(&client->dev.kobj, &tmp102_attr_group);

  
  	/* Stop monitoring if device was stopped originally */
  	if (tmp102->config_orig & TMP102_CONF_SD) {
  		int config;

  		config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);

  		if (config >= 0)

  			i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
  						     config | TMP102_CONF_SD);

  	}

  	kfree(tmp102);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int tmp102_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);

  	int config;

  	config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);

  	if (config < 0)
  		return config;

  	config |= TMP102_CONF_SD;

  	return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);

  }
  
  static int tmp102_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);

  	int config;

  	config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG);

  	if (config < 0)
  		return config;

  	config &= ~TMP102_CONF_SD;

  	return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config);

  }
  
  static const struct dev_pm_ops tmp102_dev_pm_ops = {
  	.suspend	= tmp102_suspend,
  	.resume		= tmp102_resume,
  };
  
  #define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
  #else
  #define	TMP102_DEV_PM_OPS NULL
  #endif /* CONFIG_PM */

  static const struct i2c_device_id tmp102_id[] = {

  	{ "tmp102", 0 },

  	{ }
  };

  MODULE_DEVICE_TABLE(i2c, tmp102_id);

  
  static struct i2c_driver tmp102_driver = {
  	.driver.name	= DRIVER_NAME,
  	.driver.pm	= TMP102_DEV_PM_OPS,

  	.probe		= tmp102_probe,
  	.remove		= __devexit_p(tmp102_remove),
  	.id_table	= tmp102_id,

  };
  
  static int __init tmp102_init(void)
  {
  	return i2c_add_driver(&tmp102_driver);
  }
  module_init(tmp102_init);
  
  static void __exit tmp102_exit(void)
  {
  	i2c_del_driver(&tmp102_driver);
  }
  module_exit(tmp102_exit);

  MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
  MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
  MODULE_LICENSE("GPL");