/*
   * LM73 Sensor driver
   * Based on LM75
   *
   * Copyright (C) 2007, CenoSYS (www.cenosys.com).
   * Copyright (C) 2009, Bollore telecom (www.bolloretelecom.eu).
   *
   * Guillaume Ligneul <guillaume.ligneul@gmail.com>
   * Adrien Demarez <adrien.demarez@bolloretelecom.eu>
   * Jeremy Laine <jeremy.laine@bolloretelecom.eu>
   * Chris Verges <kg4ysn@gmail.com>
   *
   * This software program is licensed subject to the GNU General Public License
   * (GPL).Version 2,June 1991, available at
   * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  
  
  /* Addresses scanned */
  static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4c,
  					0x4d, 0x4e, I2C_CLIENT_END };
  
  /* LM73 registers */
  #define LM73_REG_INPUT		0x00
  #define LM73_REG_CONF		0x01
  #define LM73_REG_MAX		0x02
  #define LM73_REG_MIN		0x03
  #define LM73_REG_CTRL		0x04
  #define LM73_REG_ID		0x07
  
  #define LM73_ID			0x9001	/* 0x0190, byte-swapped */
  #define DRVNAME			"lm73"
  #define LM73_TEMP_MIN		(-256000 / 250)
  #define LM73_TEMP_MAX		(255750 / 250)
  
  #define LM73_CTRL_RES_SHIFT	5
  #define LM73_CTRL_RES_MASK	(BIT(5) | BIT(6))
  #define LM73_CTRL_TO_MASK	BIT(7)
  
  #define LM73_CTRL_HI_SHIFT	2
  #define LM73_CTRL_LO_SHIFT	1
  
  static const unsigned short lm73_convrates[] = {
  	14,	/* 11-bits (0.25000 C/LSB): RES1 Bit = 0, RES0 Bit = 0 */
  	28,	/* 12-bits (0.12500 C/LSB): RES1 Bit = 0, RES0 Bit = 1 */
  	56,	/* 13-bits (0.06250 C/LSB): RES1 Bit = 1, RES0 Bit = 0 */
  	112,	/* 14-bits (0.03125 C/LSB): RES1 Bit = 1, RES0 Bit = 1 */
  };
  
  struct lm73_data {
  	struct i2c_client *client;
  	struct mutex lock;
  	u8 ctrl;			/* control register value */
  };
  
  /*-----------------------------------------------------------------------*/
  
  static ssize_t set_temp(struct device *dev, struct device_attribute *da,
  			const char *buf, size_t count)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct lm73_data *data = dev_get_drvdata(dev);
  	long temp;
  	short value;
  	s32 err;
  
  	int status = kstrtol(buf, 10, &temp);
  	if (status < 0)
  		return status;
  
  	/* Write value */
  	value = clamp_val(temp / 250, LM73_TEMP_MIN, LM73_TEMP_MAX) << 5;
  	err = i2c_smbus_write_word_swapped(data->client, attr->index, value);
  	return (err < 0) ? err : count;
  }
  
  static ssize_t show_temp(struct device *dev, struct device_attribute *da,
  			 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct lm73_data *data = dev_get_drvdata(dev);
  	int temp;
  
  	s32 err = i2c_smbus_read_word_swapped(data->client, attr->index);
  	if (err < 0)
  		return err;
  
  	/* use integer division instead of equivalent right shift to
  	   guarantee arithmetic shift and preserve the sign */
  	temp = (((s16) err) * 250) / 32;
  	return scnprintf(buf, PAGE_SIZE, "%d
  ", temp);
  }
  
  static ssize_t set_convrate(struct device *dev, struct device_attribute *da,
  			    const char *buf, size_t count)
  {
  	struct lm73_data *data = dev_get_drvdata(dev);
  	unsigned long convrate;
  	s32 err;
  	int res = 0;
  
  	err = kstrtoul(buf, 10, &convrate);
  	if (err < 0)
  		return err;
  
  	/*
  	 * Convert the desired conversion rate into register bits.
  	 * res is already initialized, and everything past the second-to-last
  	 * value in the array is treated as belonging to the last value
  	 * in the array.
  	 */
  	while (res < (ARRAY_SIZE(lm73_convrates) - 1) &&
  			convrate > lm73_convrates[res])
  		res++;
  
  	mutex_lock(&data->lock);
  	data->ctrl &= LM73_CTRL_TO_MASK;
  	data->ctrl |= res << LM73_CTRL_RES_SHIFT;
  	err = i2c_smbus_write_byte_data(data->client, LM73_REG_CTRL,
  					data->ctrl);
  	mutex_unlock(&data->lock);
  
  	if (err < 0)
  		return err;
  
  	return count;
  }
  
  static ssize_t show_convrate(struct device *dev, struct device_attribute *da,
  			     char *buf)
  {
  	struct lm73_data *data = dev_get_drvdata(dev);
  	int res;
  
  	res = (data->ctrl & LM73_CTRL_RES_MASK) >> LM73_CTRL_RES_SHIFT;
  	return scnprintf(buf, PAGE_SIZE, "%hu
  ", lm73_convrates[res]);
  }
  
  static ssize_t show_maxmin_alarm(struct device *dev,
  				 struct device_attribute *da, char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct lm73_data *data = dev_get_drvdata(dev);
  	s32 ctrl;
  
  	mutex_lock(&data->lock);
  	ctrl = i2c_smbus_read_byte_data(data->client, LM73_REG_CTRL);
  	if (ctrl < 0)
  		goto abort;
  	data->ctrl = ctrl;
  	mutex_unlock(&data->lock);
  
  	return scnprintf(buf, PAGE_SIZE, "%d
  ", (ctrl >> attr->index) & 1);
  
  abort:
  	mutex_unlock(&data->lock);
  	return ctrl;
  }
  
  /*-----------------------------------------------------------------------*/
  
  /* sysfs attributes for hwmon */
  
  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  			show_temp, set_temp, LM73_REG_MAX);
  static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  			show_temp, set_temp, LM73_REG_MIN);
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO,
  			show_temp, NULL, LM73_REG_INPUT);
  static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
  			show_convrate, set_convrate, 0);
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO,
  			show_maxmin_alarm, NULL, LM73_CTRL_HI_SHIFT);
  static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO,
  			show_maxmin_alarm, NULL, LM73_CTRL_LO_SHIFT);
  
  static struct attribute *lm73_attrs[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_min.dev_attr.attr,
  	&sensor_dev_attr_update_interval.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(lm73);
  
  /*-----------------------------------------------------------------------*/
  
  /* device probe and removal */
  
  static int
  lm73_probe(struct i2c_client *client, const struct i2c_device_id *id)
  {
  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;
  	struct lm73_data *data;
  	int ctrl;
  
  	data = devm_kzalloc(dev, sizeof(struct lm73_data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	data->client = client;
  	mutex_init(&data->lock);
  
  	ctrl = i2c_smbus_read_byte_data(client, LM73_REG_CTRL);
  	if (ctrl < 0)
  		return ctrl;
  	data->ctrl = ctrl;
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
  							   data, lm73_groups);
  	if (IS_ERR(hwmon_dev))
  		return PTR_ERR(hwmon_dev);
  
  	dev_info(dev, "sensor '%s'
  ", client->name);
  
  	return 0;
  }
  
  static const struct i2c_device_id lm73_ids[] = {
  	{ "lm73", 0 },
  	{ /* LIST END */ }
  };
  MODULE_DEVICE_TABLE(i2c, lm73_ids);
  
  /* Return 0 if detection is successful, -ENODEV otherwise */
  static int lm73_detect(struct i2c_client *new_client,
  			struct i2c_board_info *info)
  {
  	struct i2c_adapter *adapter = new_client->adapter;
  	int id, ctrl, conf;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
  					I2C_FUNC_SMBUS_WORD_DATA))
  		return -ENODEV;
  
  	/*
  	 * Do as much detection as possible with byte reads first, as word
  	 * reads can confuse other devices.
  	 */
  	ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
  	if (ctrl < 0 || (ctrl & 0x10))
  		return -ENODEV;
  
  	conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
  	if (conf < 0 || (conf & 0x0c))
  		return -ENODEV;
  
  	id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
  	if (id < 0 || id != (LM73_ID & 0xff))
  		return -ENODEV;
  
  	/* Check device ID */
  	id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
  	if (id < 0 || id != LM73_ID)
  		return -ENODEV;
  
  	strlcpy(info->type, "lm73", I2C_NAME_SIZE);
  
  	return 0;
  }
  
  static struct i2c_driver lm73_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "lm73",
  	},
  	.probe		= lm73_probe,
  	.id_table	= lm73_ids,
  	.detect		= lm73_detect,
  	.address_list	= normal_i2c,
  };
  
  module_i2c_driver(lm73_driver);
  
  MODULE_AUTHOR("Guillaume Ligneul <guillaume.ligneul@gmail.com>");
  MODULE_DESCRIPTION("LM73 driver");
  MODULE_LICENSE("GPL");