/*
   * max1619.c - Part of lm_sensors, Linux kernel modules for hardware
   *             monitoring
   * Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
   *                         Jean Delvare <jdelvare@suse.de>
   *
   * Based on the lm90 driver. The MAX1619 is a sensor chip made by Maxim.
   * It reports up to two temperatures (its own plus up to
   * one external one). Complete datasheet can be
   * obtained from Maxim's website at:
   *   http://pdfserv.maxim-ic.com/en/ds/MAX1619.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.
   */
  
  #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>
  
  static const unsigned short normal_i2c[] = {
  	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
  
  /*
   * The MAX1619 registers
   */
  
  #define MAX1619_REG_R_MAN_ID		0xFE
  #define MAX1619_REG_R_CHIP_ID		0xFF
  #define MAX1619_REG_R_CONFIG		0x03
  #define MAX1619_REG_W_CONFIG		0x09
  #define MAX1619_REG_R_CONVRATE		0x04
  #define MAX1619_REG_W_CONVRATE		0x0A
  #define MAX1619_REG_R_STATUS		0x02
  #define MAX1619_REG_R_LOCAL_TEMP	0x00
  #define MAX1619_REG_R_REMOTE_TEMP	0x01
  #define MAX1619_REG_R_REMOTE_HIGH	0x07
  #define MAX1619_REG_W_REMOTE_HIGH	0x0D
  #define MAX1619_REG_R_REMOTE_LOW	0x08
  #define MAX1619_REG_W_REMOTE_LOW	0x0E
  #define MAX1619_REG_R_REMOTE_CRIT	0x10
  #define MAX1619_REG_W_REMOTE_CRIT	0x12
  #define MAX1619_REG_R_TCRIT_HYST	0x11
  #define MAX1619_REG_W_TCRIT_HYST	0x13
  
  /*
   * Conversions
   */
  
  static int temp_from_reg(int val)
  {
  	return (val & 0x80 ? val-0x100 : val) * 1000;
  }
  
  static int temp_to_reg(int val)
  {
  	return (val < 0 ? val+0x100*1000 : val) / 1000;
  }
  
  enum temp_index {
  	t_input1 = 0,
  	t_input2,
  	t_low2,
  	t_high2,
  	t_crit2,
  	t_hyst2,
  	t_num_regs
  };
  
  /*
   * Client data (each client gets its own)
   */
  
  struct max1619_data {
  	struct i2c_client *client;
  	struct mutex update_lock;
  	char valid; /* zero until following fields are valid */
  	unsigned long last_updated; /* in jiffies */
  
  	/* registers values */
  	u8 temp[t_num_regs];	/* index with enum temp_index */
  	u8 alarms;
  };
  
  static const u8 regs_read[t_num_regs] = {
  	[t_input1] = MAX1619_REG_R_LOCAL_TEMP,
  	[t_input2] = MAX1619_REG_R_REMOTE_TEMP,
  	[t_low2] = MAX1619_REG_R_REMOTE_LOW,
  	[t_high2] = MAX1619_REG_R_REMOTE_HIGH,
  	[t_crit2] = MAX1619_REG_R_REMOTE_CRIT,
  	[t_hyst2] = MAX1619_REG_R_TCRIT_HYST,
  };
  
  static const u8 regs_write[t_num_regs] = {
  	[t_low2] = MAX1619_REG_W_REMOTE_LOW,
  	[t_high2] = MAX1619_REG_W_REMOTE_HIGH,
  	[t_crit2] = MAX1619_REG_W_REMOTE_CRIT,
  	[t_hyst2] = MAX1619_REG_W_TCRIT_HYST,
  };
  
  static struct max1619_data *max1619_update_device(struct device *dev)
  {
  	struct max1619_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;
  	int config, i;
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
  		dev_dbg(&client->dev, "Updating max1619 data.
  ");
  		for (i = 0; i < t_num_regs; i++)
  			data->temp[i] = i2c_smbus_read_byte_data(client,
  					regs_read[i]);
  		data->alarms = i2c_smbus_read_byte_data(client,
  					MAX1619_REG_R_STATUS);
  		/* If OVERT polarity is low, reverse alarm bit */
  		config = i2c_smbus_read_byte_data(client, MAX1619_REG_R_CONFIG);
  		if (!(config & 0x20))
  			data->alarms ^= 0x02;
  
  		data->last_updated = jiffies;
  		data->valid = 1;
  	}
  
  	mutex_unlock(&data->update_lock);
  
  	return data;
  }
  
  /*
   * Sysfs stuff
   */
  
  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 max1619_data *data = max1619_update_device(dev);
  
  	return sprintf(buf, "%d
  ", temp_from_reg(data->temp[attr->index]));
  }
  
  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 max1619_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;
  	long val;
  	int err = kstrtol(buf, 10, &val);
  	if (err)
  		return err;
  
  	mutex_lock(&data->update_lock);
  	data->temp[attr->index] = temp_to_reg(val);
  	i2c_smbus_write_byte_data(client, regs_write[attr->index],
  				  data->temp[attr->index]);
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t show_alarms(struct device *dev, struct device_attribute *attr,
  			   char *buf)
  {
  	struct max1619_data *data = max1619_update_device(dev);
  	return sprintf(buf, "%d
  ", data->alarms);
  }
  
  static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int bitnr = to_sensor_dev_attr(attr)->index;
  	struct max1619_data *data = max1619_update_device(dev);
  	return sprintf(buf, "%d
  ", (data->alarms >> bitnr) & 1);
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input1);
  static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, t_input2);
  static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
  			  t_low2);
  static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
  			  t_high2);
  static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
  			  t_crit2);
  static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_temp,
  			  set_temp, t_hyst2);
  
  static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
  static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 1);
  static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
  
  static struct attribute *max1619_attrs[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_min.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
  	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
  
  	&dev_attr_alarms.attr,
  	&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_fault.dev_attr.attr,
  	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(max1619);
  
  /* Return 0 if detection is successful, -ENODEV otherwise */
  static int max1619_detect(struct i2c_client *client,
  			  struct i2c_board_info *info)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	u8 reg_config, reg_convrate, reg_status, man_id, chip_id;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;
  
  	/* detection */
  	reg_config = i2c_smbus_read_byte_data(client, MAX1619_REG_R_CONFIG);
  	reg_convrate = i2c_smbus_read_byte_data(client, MAX1619_REG_R_CONVRATE);
  	reg_status = i2c_smbus_read_byte_data(client, MAX1619_REG_R_STATUS);
  	if ((reg_config & 0x03) != 0x00
  	 || reg_convrate > 0x07 || (reg_status & 0x61) != 0x00) {
  		dev_dbg(&adapter->dev, "MAX1619 detection failed at 0x%02x
  ",
  			client->addr);
  		return -ENODEV;
  	}
  
  	/* identification */
  	man_id = i2c_smbus_read_byte_data(client, MAX1619_REG_R_MAN_ID);
  	chip_id = i2c_smbus_read_byte_data(client, MAX1619_REG_R_CHIP_ID);
  	if (man_id != 0x4D || chip_id != 0x04) {
  		dev_info(&adapter->dev,
  			 "Unsupported chip (man_id=0x%02X, chip_id=0x%02X).
  ",
  			 man_id, chip_id);
  		return -ENODEV;
  	}
  
  	strlcpy(info->type, "max1619", I2C_NAME_SIZE);
  
  	return 0;
  }
  
  static void max1619_init_client(struct i2c_client *client)
  {
  	u8 config;
  
  	/*
  	 * Start the conversions.
  	 */
  	i2c_smbus_write_byte_data(client, MAX1619_REG_W_CONVRATE,
  				  5); /* 2 Hz */
  	config = i2c_smbus_read_byte_data(client, MAX1619_REG_R_CONFIG);
  	if (config & 0x40)
  		i2c_smbus_write_byte_data(client, MAX1619_REG_W_CONFIG,
  					  config & 0xBF); /* run */
  }
  
  static int max1619_probe(struct i2c_client *new_client,
  			 const struct i2c_device_id *id)
  {
  	struct max1619_data *data;
  	struct device *hwmon_dev;
  
  	data = devm_kzalloc(&new_client->dev, sizeof(struct max1619_data),
  			    GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	data->client = new_client;
  	mutex_init(&data->update_lock);
  
  	/* Initialize the MAX1619 chip */
  	max1619_init_client(new_client);
  
  	hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
  							   new_client->name,
  							   data,
  							   max1619_groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);
  }
  
  static const struct i2c_device_id max1619_id[] = {
  	{ "max1619", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, max1619_id);
  
  static struct i2c_driver max1619_driver = {
  	.class		= I2C_CLASS_HWMON,
  	.driver = {
  		.name	= "max1619",
  	},
  	.probe		= max1619_probe,
  	.id_table	= max1619_id,
  	.detect		= max1619_detect,
  	.address_list	= normal_i2c,
  };
  
  module_i2c_driver(max1619_driver);
  
  MODULE_AUTHOR("Oleksij Rempel <bug-track@fisher-privat.net>, Jean Delvare <jdelvare@suse.de>");
  MODULE_DESCRIPTION("MAX1619 sensor driver");
  MODULE_LICENSE("GPL");