/*

   * Copyright (C) 2008, 2010 Davide Rizzo <elpa.rizzo@gmail.com>

   *

   * The LM95241 is a sensor chip made by National Semiconductors.
   * It reports up to three temperatures (its own plus up to two external ones).
   * Complete datasheet can be obtained from National's website at:

   *   http://www.national.com/ds.cgi/LM/LM95241.pdf
   *
   * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #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/sysfs.h>

  #define DEVNAME "lm95241"

  static const unsigned short normal_i2c[] = {

  	0x19, 0x2a, 0x2b, I2C_CLIENT_END };

  /* LM95241 registers */
  #define LM95241_REG_R_MAN_ID		0xFE
  #define LM95241_REG_R_CHIP_ID		0xFF
  #define LM95241_REG_R_STATUS		0x02
  #define LM95241_REG_RW_CONFIG		0x03
  #define LM95241_REG_RW_REM_FILTER	0x06
  #define LM95241_REG_RW_TRUTHERM		0x07

  #define LM95241_REG_W_ONE_SHOT		0x0F

  #define LM95241_REG_R_LOCAL_TEMPH	0x10
  #define LM95241_REG_R_REMOTE1_TEMPH	0x11
  #define LM95241_REG_R_REMOTE2_TEMPH	0x12
  #define LM95241_REG_R_LOCAL_TEMPL	0x20
  #define LM95241_REG_R_REMOTE1_TEMPL	0x21
  #define LM95241_REG_R_REMOTE2_TEMPL	0x22
  #define LM95241_REG_RW_REMOTE_MODEL	0x30
  
  /* LM95241 specific bitfields */
  #define CFG_STOP 0x40
  #define CFG_CR0076 0x00
  #define CFG_CR0182 0x10
  #define CFG_CR1000 0x20
  #define CFG_CR2700 0x30
  #define R1MS_SHIFT 0
  #define R2MS_SHIFT 2
  #define R1MS_MASK (0x01 << (R1MS_SHIFT))
  #define R2MS_MASK (0x01 << (R2MS_SHIFT))
  #define R1DF_SHIFT 1
  #define R2DF_SHIFT 2
  #define R1DF_MASK (0x01 << (R1DF_SHIFT))
  #define R2DF_MASK (0x01 << (R2DF_SHIFT))
  #define R1FE_MASK 0x01
  #define R2FE_MASK 0x05
  #define TT1_SHIFT 0
  #define TT2_SHIFT 4
  #define TT_OFF 0
  #define TT_ON 1
  #define TT_MASK 7

  #define NATSEMI_MAN_ID	0x01
  #define LM95231_CHIP_ID	0xA1
  #define LM95241_CHIP_ID	0xA4

  static const u8 lm95241_reg_address[] = {
  	LM95241_REG_R_LOCAL_TEMPH,
  	LM95241_REG_R_LOCAL_TEMPL,
  	LM95241_REG_R_REMOTE1_TEMPH,
  	LM95241_REG_R_REMOTE1_TEMPL,
  	LM95241_REG_R_REMOTE2_TEMPH,
  	LM95241_REG_R_REMOTE2_TEMPL
  };

  /* Client data (each client gets its own) */
  struct lm95241_data {

  	struct device *hwmon_dev;
  	struct mutex update_lock;

  	unsigned long last_updated, interval;	/* in jiffies */
  	char valid;		/* zero until following fields are valid */

  	/* registers values */

  	u8 temp[ARRAY_SIZE(lm95241_reg_address)];

  	u8 config, model, trutherm;
  };

  /* Conversions */

  static int temp_from_reg_signed(u8 val_h, u8 val_l)

  {

  	s16 val_hl = (val_h << 8) | val_l;
  	return val_hl * 1000 / 256;
  }
  
  static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
  {
  	u16 val_hl = (val_h << 8) | val_l;
  	return val_hl * 1000 / 256;

  }
  
  static struct lm95241_data *lm95241_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + data->interval) ||
  	    !data->valid) {
  		int i;
  
  		dev_dbg(&client->dev, "Updating lm95241 data.
  ");
  		for (i = 0; i < ARRAY_SIZE(lm95241_reg_address); i++)
  			data->temp[i]
  			  = i2c_smbus_read_byte_data(client,
  						     lm95241_reg_address[i]);
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return data;
  }

  /* Sysfs stuff */

  static ssize_t show_input(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	struct lm95241_data *data = lm95241_update_device(dev);

  	int index = to_sensor_dev_attr(attr)->index;

  
  	return snprintf(buf, PAGE_SIZE - 1, "%d
  ",

  			index == 0 || (data->config & (1 << (index / 2))) ?
  		temp_from_reg_signed(data->temp[index], data->temp[index + 1]) :
  		temp_from_reg_unsigned(data->temp[index],
  				       data->temp[index + 1]));

  }

  static ssize_t show_type(struct device *dev, struct device_attribute *attr,

  			 char *buf)
  {

  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);

  	return snprintf(buf, PAGE_SIZE - 1,
  		data->model & to_sensor_dev_attr(attr)->index ? "1
  " : "2
  ");

  }

  static ssize_t set_type(struct device *dev, struct device_attribute *attr,

  			const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);

  	unsigned long val;

  	int shift;
  	u8 mask = to_sensor_dev_attr(attr)->index;

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

  		return -EINVAL;

  	if (val != 1 && val != 2)
  		return -EINVAL;

  	shift = mask == R1MS_MASK ? TT1_SHIFT : TT2_SHIFT;
  
  	mutex_lock(&data->update_lock);
  
  	data->trutherm &= ~(TT_MASK << shift);
  	if (val == 1) {
  		data->model |= mask;
  		data->trutherm |= (TT_ON << shift);
  	} else {
  		data->model &= ~mask;
  		data->trutherm |= (TT_OFF << shift);
  	}
  	data->valid = 0;
  
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_REMOTE_MODEL,
  				  data->model);
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
  				  data->trutherm);
  
  	mutex_unlock(&data->update_lock);

  
  	return count;
  }

  static ssize_t show_min(struct device *dev, struct device_attribute *attr,
  			char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  
  	return snprintf(buf, PAGE_SIZE - 1,
  			data->config & to_sensor_dev_attr(attr)->index ?
  			"-127000
  " : "0
  ");

  }

  
  static ssize_t set_min(struct device *dev, struct device_attribute *attr,
  		       const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  	long val;

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

  		return -EINVAL;
  	if (val < -128000)
  		return -EINVAL;
  
  	mutex_lock(&data->update_lock);
  
  	if (val < 0)
  		data->config |= to_sensor_dev_attr(attr)->index;
  	else
  		data->config &= ~to_sensor_dev_attr(attr)->index;
  	data->valid = 0;
  
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);
  
  	mutex_unlock(&data->update_lock);
  
  	return count;

  }

  
  static ssize_t show_max(struct device *dev, struct device_attribute *attr,
  			char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  
  	return snprintf(buf, PAGE_SIZE - 1,
  			data->config & to_sensor_dev_attr(attr)->index ?
  			"127000
  " : "255000
  ");

  }

  
  static ssize_t set_max(struct device *dev, struct device_attribute *attr,
  		       const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  	long val;

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

  		return -EINVAL;
  	if (val >= 256000)
  		return -EINVAL;
  
  	mutex_lock(&data->update_lock);
  
  	if (val <= 127000)
  		data->config |= to_sensor_dev_attr(attr)->index;
  	else
  		data->config &= ~to_sensor_dev_attr(attr)->index;
  	data->valid = 0;
  
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);
  
  	mutex_unlock(&data->update_lock);
  
  	return count;

  }

  
  static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
  			     char *buf)
  {
  	struct lm95241_data *data = lm95241_update_device(dev);
  
  	return snprintf(buf, PAGE_SIZE - 1, "%lu
  ", 1000 * data->interval
  			/ HZ);

  }

  
  static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
  			    const char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct lm95241_data *data = i2c_get_clientdata(client);
  	unsigned long val;

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

  		return -EINVAL;
  
  	data->interval = val * HZ / 1000;
  
  	return count;

  }

  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_input, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type, set_type,
  			  R1MS_MASK);
  static SENSOR_DEVICE_ATTR(temp3_type, S_IWUSR | S_IRUGO, show_type, set_type,
  			  R2MS_MASK);
  static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_min, set_min,
  			  R1DF_MASK);
  static SENSOR_DEVICE_ATTR(temp3_min, S_IWUSR | S_IRUGO, show_min, set_min,
  			  R2DF_MASK);
  static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_max, set_max,
  			  R1DF_MASK);
  static SENSOR_DEVICE_ATTR(temp3_max, S_IWUSR | S_IRUGO, show_max, set_max,
  			  R2DF_MASK);

  static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
  		   set_interval);

  
  static struct attribute *lm95241_attributes[] = {

  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_type.dev_attr.attr,
  	&sensor_dev_attr_temp3_type.dev_attr.attr,
  	&sensor_dev_attr_temp2_min.dev_attr.attr,
  	&sensor_dev_attr_temp3_min.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,

  	&dev_attr_update_interval.attr,

  	NULL
  };
  
  static const struct attribute_group lm95241_group = {
  	.attrs = lm95241_attributes,
  };

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

  static int lm95241_detect(struct i2c_client *new_client,

  			  struct i2c_board_info *info)

  {

  	struct i2c_adapter *adapter = new_client->adapter;

  	const char *name;

  	int mfg_id, chip_id;

  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))

  		return -ENODEV;

  	mfg_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_MAN_ID);
  	if (mfg_id != NATSEMI_MAN_ID)
  		return -ENODEV;
  
  	chip_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_CHIP_ID);
  	switch (chip_id) {
  	case LM95231_CHIP_ID:
  		name = "lm95231";
  		break;
  	case LM95241_CHIP_ID:
  		name = "lm95241";
  		break;
  	default:

  		return -ENODEV;

  	}

  	/* Fill the i2c board info */

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

  static void lm95241_init_client(struct i2c_client *client)
  {
  	struct lm95241_data *data = i2c_get_clientdata(client);
  
  	data->interval = HZ;	/* 1 sec default */
  	data->valid = 0;
  	data->config = CFG_CR0076;
  	data->model = 0;
  	data->trutherm = (TT_OFF << TT1_SHIFT) | (TT_OFF << TT2_SHIFT);
  
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_REM_FILTER,
  				  R1FE_MASK | R2FE_MASK);
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
  				  data->trutherm);
  	i2c_smbus_write_byte_data(client, LM95241_REG_RW_REMOTE_MODEL,
  				  data->model);
  }

  static int lm95241_probe(struct i2c_client *new_client,
  			 const struct i2c_device_id *id)
  {
  	struct lm95241_data *data;
  	int err;

  	data = kzalloc(sizeof(struct lm95241_data), GFP_KERNEL);
  	if (!data) {
  		err = -ENOMEM;
  		goto exit;
  	}
  
  	i2c_set_clientdata(new_client, data);
  	mutex_init(&data->update_lock);

  
  	/* Initialize the LM95241 chip */
  	lm95241_init_client(new_client);
  
  	/* Register sysfs hooks */
  	err = sysfs_create_group(&new_client->dev.kobj, &lm95241_group);
  	if (err)

  		goto exit_free;

  
  	data->hwmon_dev = hwmon_device_register(&new_client->dev);
  	if (IS_ERR(data->hwmon_dev)) {
  		err = PTR_ERR(data->hwmon_dev);
  		goto exit_remove_files;
  	}
  
  	return 0;
  
  exit_remove_files:
  	sysfs_remove_group(&new_client->dev.kobj, &lm95241_group);

  exit_free:
  	kfree(data);
  exit:
  	return err;
  }

  static int lm95241_remove(struct i2c_client *client)

  {
  	struct lm95241_data *data = i2c_get_clientdata(client);

  
  	hwmon_device_unregister(data->hwmon_dev);
  	sysfs_remove_group(&client->dev.kobj, &lm95241_group);

  	kfree(data);
  	return 0;
  }

  /* Driver data (common to all clients) */
  static const struct i2c_device_id lm95241_id[] = {

  	{ "lm95231", 0 },
  	{ "lm95241", 0 },

  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lm95241_id);
  
  static struct i2c_driver lm95241_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {

  		.name	= DEVNAME,

  	},
  	.probe		= lm95241_probe,
  	.remove		= lm95241_remove,
  	.id_table	= lm95241_id,
  	.detect		= lm95241_detect,

  	.address_list	= normal_i2c,

  };

  static int __init sensors_lm95241_init(void)
  {
  	return i2c_add_driver(&lm95241_driver);
  }
  
  static void __exit sensors_lm95241_exit(void)
  {
  	i2c_del_driver(&lm95241_driver);
  }

  MODULE_AUTHOR("Davide Rizzo <elpa.rizzo@gmail.com>");

  MODULE_DESCRIPTION("LM95241 sensor driver");
  MODULE_LICENSE("GPL");
  
  module_init(sensors_lm95241_init);
  module_exit(sensors_lm95241_exit);