/*
   * An hwmon driver for the Analog Devices AD7416/17/18
   * Copyright (C) 2006-07 Tower Technologies
   *
   * Author: Alessandro Zummo <a.zummo@towertech.it>
   *
   * Based on lm75.c
   * Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
   *
   * 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 - version 2.
   */
  
  #include <linux/module.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/delay.h>
  #include <linux/slab.h>
  
  #include "lm75.h"
  
  #define DRV_VERSION "0.4"
  
  enum chips { ad7416, ad7417, ad7418 };
  
  /* AD7418 registers */
  #define AD7418_REG_TEMP_IN	0x00
  #define AD7418_REG_CONF		0x01
  #define AD7418_REG_TEMP_HYST	0x02
  #define AD7418_REG_TEMP_OS	0x03
  #define AD7418_REG_ADC		0x04
  #define AD7418_REG_CONF2	0x05
  
  #define AD7418_REG_ADC_CH(x)	((x) << 5)
  #define AD7418_CH_TEMP		AD7418_REG_ADC_CH(0)
  
  static const u8 AD7418_REG_TEMP[] = { AD7418_REG_TEMP_IN,
  					AD7418_REG_TEMP_HYST,
  					AD7418_REG_TEMP_OS };
  
  struct ad7418_data {
  	struct device		*hwmon_dev;
  	struct attribute_group	attrs;
  	enum chips		type;
  	struct mutex		lock;
  	int			adc_max;	/* number of ADC channels */
  	char			valid;
  	unsigned long		last_updated;	/* In jiffies */
  	s16			temp[3];	/* Register values */
  	u16			in[4];
  };
  
  static int ad7418_probe(struct i2c_client *client,
  			const struct i2c_device_id *id);
  static int ad7418_remove(struct i2c_client *client);
  
  static const struct i2c_device_id ad7418_id[] = {
  	{ "ad7416", ad7416 },
  	{ "ad7417", ad7417 },
  	{ "ad7418", ad7418 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, ad7418_id);
  
  static struct i2c_driver ad7418_driver = {
  	.driver = {
  		.name	= "ad7418",
  	},
  	.probe		= ad7418_probe,
  	.remove		= ad7418_remove,
  	.id_table	= ad7418_id,
  };
  
  static void ad7418_init_client(struct i2c_client *client)
  {
  	struct ad7418_data *data = i2c_get_clientdata(client);
  
  	int reg = i2c_smbus_read_byte_data(client, AD7418_REG_CONF);
  	if (reg < 0) {
  		dev_err(&client->dev, "cannot read configuration register
  ");
  	} else {
  		dev_info(&client->dev, "configuring for mode 1
  ");
  		i2c_smbus_write_byte_data(client, AD7418_REG_CONF, reg & 0xfe);
  
  		if (data->type == ad7417 || data->type == ad7418)
  			i2c_smbus_write_byte_data(client,
  						AD7418_REG_CONF2, 0x00);
  	}
  }
  
  static struct ad7418_data *ad7418_update_device(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct ad7418_data *data = i2c_get_clientdata(client);
  
  	mutex_lock(&data->lock);
  
  	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
  		|| !data->valid) {
  		u8 cfg;
  		int i, ch;
  
  		/* read config register and clear channel bits */
  		cfg = i2c_smbus_read_byte_data(client, AD7418_REG_CONF);
  		cfg &= 0x1F;
  
  		i2c_smbus_write_byte_data(client, AD7418_REG_CONF,
  						cfg | AD7418_CH_TEMP);
  		udelay(30);
  
  		for (i = 0; i < 3; i++) {
  			data->temp[i] =
  				i2c_smbus_read_word_swapped(client,
  						AD7418_REG_TEMP[i]);
  		}
  
  		for (i = 0, ch = 4; i < data->adc_max; i++, ch--) {
  			i2c_smbus_write_byte_data(client,
  					AD7418_REG_CONF,
  					cfg | AD7418_REG_ADC_CH(ch));
  
  			udelay(15);
  			data->in[data->adc_max - 1 - i] =
  				i2c_smbus_read_word_swapped(client,
  						AD7418_REG_ADC);
  		}
  
  		/* restore old configuration value */
  		i2c_smbus_write_word_swapped(client, AD7418_REG_CONF, cfg);
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->lock);
  
  	return data;
  }
  
  static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
  			char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct ad7418_data *data = ad7418_update_device(dev);
  	return sprintf(buf, "%d
  ",
  		LM75_TEMP_FROM_REG(data->temp[attr->index]));
  }
  
  static ssize_t show_adc(struct device *dev, struct device_attribute *devattr,
  			char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct ad7418_data *data = ad7418_update_device(dev);
  
  	return sprintf(buf, "%d
  ",
  		((data->in[attr->index] >> 6) * 2500 + 512) / 1024);
  }
  
  static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
  			const char *buf, size_t count)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
  	struct i2c_client *client = to_i2c_client(dev);
  	struct ad7418_data *data = i2c_get_clientdata(client);
  	long temp;
  	int ret = kstrtol(buf, 10, &temp);
  
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->lock);
  	data->temp[attr->index] = LM75_TEMP_TO_REG(temp);
  	i2c_smbus_write_word_swapped(client,
  				     AD7418_REG_TEMP[attr->index],
  				     data->temp[attr->index]);
  	mutex_unlock(&data->lock);
  	return count;
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
  				show_temp, set_temp, 1);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  				show_temp, set_temp, 2);
  
  static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, show_adc, NULL, 0);
  static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, show_adc, NULL, 1);
  static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, show_adc, NULL, 2);
  static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, show_adc, NULL, 3);
  
  static struct attribute *ad7416_attributes[] = {
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	NULL
  };
  
  static struct attribute *ad7417_attributes[] = {
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	&sensor_dev_attr_in2_input.dev_attr.attr,
  	&sensor_dev_attr_in3_input.dev_attr.attr,
  	&sensor_dev_attr_in4_input.dev_attr.attr,
  	NULL
  };
  
  static struct attribute *ad7418_attributes[] = {
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_in1_input.dev_attr.attr,
  	NULL
  };
  
  static int ad7418_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	struct ad7418_data *data;
  	int err;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
  					I2C_FUNC_SMBUS_WORD_DATA))
  		return -EOPNOTSUPP;
  
  	data = devm_kzalloc(&client->dev, sizeof(struct ad7418_data),
  			    GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, data);
  
  	mutex_init(&data->lock);
  	data->type = id->driver_data;
  
  	switch (data->type) {
  	case ad7416:
  		data->adc_max = 0;
  		data->attrs.attrs = ad7416_attributes;
  		break;
  
  	case ad7417:
  		data->adc_max = 4;
  		data->attrs.attrs = ad7417_attributes;
  		break;
  
  	case ad7418:
  		data->adc_max = 1;
  		data->attrs.attrs = ad7418_attributes;
  		break;
  	}
  
  	dev_info(&client->dev, "%s chip found
  ", client->name);
  
  	/* Initialize the AD7418 chip */
  	ad7418_init_client(client);
  
  	/* Register sysfs hooks */
  	err = sysfs_create_group(&client->dev.kobj, &data->attrs);
  	if (err)
  		return err;
  
  	data->hwmon_dev = hwmon_device_register(&client->dev);
  	if (IS_ERR(data->hwmon_dev)) {
  		err = PTR_ERR(data->hwmon_dev);
  		goto exit_remove;
  	}
  
  	return 0;
  
  exit_remove:
  	sysfs_remove_group(&client->dev.kobj, &data->attrs);
  	return err;
  }
  
  static int ad7418_remove(struct i2c_client *client)
  {
  	struct ad7418_data *data = i2c_get_clientdata(client);
  	hwmon_device_unregister(data->hwmon_dev);
  	sysfs_remove_group(&client->dev.kobj, &data->attrs);
  	return 0;
  }
  
  module_i2c_driver(ad7418_driver);
  
  MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
  MODULE_DESCRIPTION("AD7416/17/18 driver");
  MODULE_LICENSE("GPL");
  MODULE_VERSION(DRV_VERSION);