/*
   *  Driver for the ADT7411 (I2C/SPI 8 channel 10 bit ADC & temperature-sensor)
   *
   *  Copyright (C) 2008, 2010 Pengutronix
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License version 2 as
   *  published by the Free Software Foundation.
   *
   *  TODO: SPI, support for external temperature sensor
   *	  use power-down mode for suspend?, interrupt handling?
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/slab.h>
  
  #define ADT7411_REG_INT_TEMP_VDD_LSB		0x03
  #define ADT7411_REG_EXT_TEMP_AIN14_LSB		0x04
  #define ADT7411_REG_VDD_MSB			0x06
  #define ADT7411_REG_INT_TEMP_MSB		0x07
  #define ADT7411_REG_EXT_TEMP_AIN1_MSB		0x08
  
  #define ADT7411_REG_CFG1			0x18
  #define ADT7411_CFG1_START_MONITOR		(1 << 0)
  
  #define ADT7411_REG_CFG2			0x19
  #define ADT7411_CFG2_DISABLE_AVG		(1 << 5)
  
  #define ADT7411_REG_CFG3			0x1a
  #define ADT7411_CFG3_ADC_CLK_225		(1 << 0)
  #define ADT7411_CFG3_REF_VDD			(1 << 4)
  
  #define ADT7411_REG_DEVICE_ID			0x4d
  #define ADT7411_REG_MANUFACTURER_ID		0x4e
  
  #define ADT7411_DEVICE_ID			0x2
  #define ADT7411_MANUFACTURER_ID			0x41
  
  static const unsigned short normal_i2c[] = { 0x48, 0x4a, 0x4b, I2C_CLIENT_END };
  
  struct adt7411_data {
  	struct mutex device_lock;	/* for "atomic" device accesses */
  	struct mutex update_lock;
  	unsigned long next_update;
  	int vref_cached;
  	struct device *hwmon_dev;
  };
  
  /*
   * When reading a register containing (up to 4) lsb, all associated
   * msb-registers get locked by the hardware. After _one_ of those msb is read,
   * _all_ are unlocked. In order to use this locking correctly, reading lsb/msb
   * is protected here with a mutex, too.
   */
  static int adt7411_read_10_bit(struct i2c_client *client, u8 lsb_reg,
  				u8 msb_reg, u8 lsb_shift)
  {
  	struct adt7411_data *data = i2c_get_clientdata(client);
  	int val, tmp;
  
  	mutex_lock(&data->device_lock);
  
  	val = i2c_smbus_read_byte_data(client, lsb_reg);
  	if (val < 0)
  		goto exit_unlock;
  
  	tmp = (val >> lsb_shift) & 3;
  	val = i2c_smbus_read_byte_data(client, msb_reg);
  
  	if (val >= 0)
  		val = (val << 2) | tmp;
  
   exit_unlock:
  	mutex_unlock(&data->device_lock);
  
  	return val;
  }
  
  static int adt7411_modify_bit(struct i2c_client *client, u8 reg, u8 bit,
  				bool flag)
  {
  	struct adt7411_data *data = i2c_get_clientdata(client);
  	int ret, val;
  
  	mutex_lock(&data->device_lock);
  
  	ret = i2c_smbus_read_byte_data(client, reg);
  	if (ret < 0)
  		goto exit_unlock;
  
  	if (flag)
  		val = ret | bit;
  	else
  		val = ret & ~bit;
  
  	ret = i2c_smbus_write_byte_data(client, reg, val);
  
   exit_unlock:
  	mutex_unlock(&data->device_lock);
  	return ret;
  }
  
  static ssize_t adt7411_show_vdd(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
  			ADT7411_REG_VDD_MSB, 2);
  
  	return ret < 0 ? ret : sprintf(buf, "%u
  ", ret * 7000 / 1024);
  }
  
  static ssize_t adt7411_show_temp(struct device *dev,
  			struct device_attribute *attr, char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	int val = adt7411_read_10_bit(client, ADT7411_REG_INT_TEMP_VDD_LSB,
  			ADT7411_REG_INT_TEMP_MSB, 0);
  
  	if (val < 0)
  		return val;
  
  	val = val & 0x200 ? val - 0x400 : val; /* 10 bit signed */
  
  	return sprintf(buf, "%d
  ", val * 250);
  }
  
  static ssize_t adt7411_show_input(struct device *dev,
  				  struct device_attribute *attr, char *buf)
  {
  	int nr = to_sensor_dev_attr(attr)->index;
  	struct i2c_client *client = to_i2c_client(dev);
  	struct adt7411_data *data = i2c_get_clientdata(client);
  	int val;
  	u8 lsb_reg, lsb_shift;
  
  	mutex_lock(&data->update_lock);
  	if (time_after_eq(jiffies, data->next_update)) {
  		val = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
  		if (val < 0)
  			goto exit_unlock;
  
  		if (val & ADT7411_CFG3_REF_VDD) {
  			val = adt7411_read_10_bit(client,
  					ADT7411_REG_INT_TEMP_VDD_LSB,
  					ADT7411_REG_VDD_MSB, 2);
  			if (val < 0)
  				goto exit_unlock;
  
  			data->vref_cached = val * 7000 / 1024;
  		} else {
  			data->vref_cached = 2250;
  		}
  
  		data->next_update = jiffies + HZ;
  	}
  
  	lsb_reg = ADT7411_REG_EXT_TEMP_AIN14_LSB + (nr >> 2);
  	lsb_shift = 2 * (nr & 0x03);
  	val = adt7411_read_10_bit(client, lsb_reg,
  			ADT7411_REG_EXT_TEMP_AIN1_MSB + nr, lsb_shift);
  	if (val < 0)
  		goto exit_unlock;
  
  	val = sprintf(buf, "%u
  ", val * data->vref_cached / 1024);
   exit_unlock:
  	mutex_unlock(&data->update_lock);
  	return val;
  }
  
  static ssize_t adt7411_show_bit(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	struct sensor_device_attribute_2 *attr2 = to_sensor_dev_attr_2(attr);
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret = i2c_smbus_read_byte_data(client, attr2->index);
  
  	return ret < 0 ? ret : sprintf(buf, "%u
  ", !!(ret & attr2->nr));
  }
  
  static ssize_t adt7411_set_bit(struct device *dev,
  			       struct device_attribute *attr, const char *buf,
  			       size_t count)
  {
  	struct sensor_device_attribute_2 *s_attr2 = to_sensor_dev_attr_2(attr);
  	struct i2c_client *client = to_i2c_client(dev);
  	struct adt7411_data *data = i2c_get_clientdata(client);
  	int ret;
  	unsigned long flag;
  
  	ret = kstrtoul(buf, 0, &flag);
  	if (ret || flag > 1)
  		return -EINVAL;
  
  	ret = adt7411_modify_bit(client, s_attr2->index, s_attr2->nr, flag);
  
  	/* force update */
  	mutex_lock(&data->update_lock);
  	data->next_update = jiffies;
  	mutex_unlock(&data->update_lock);
  
  	return ret < 0 ? ret : count;
  }
  
  #define ADT7411_BIT_ATTR(__name, __reg, __bit) \
  	SENSOR_DEVICE_ATTR_2(__name, S_IRUGO | S_IWUSR, adt7411_show_bit, \
  	adt7411_set_bit, __bit, __reg)
  
  static DEVICE_ATTR(temp1_input, S_IRUGO, adt7411_show_temp, NULL);
  static DEVICE_ATTR(in0_input, S_IRUGO, adt7411_show_vdd, NULL);
  static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, adt7411_show_input, NULL, 0);
  static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, adt7411_show_input, NULL, 1);
  static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, adt7411_show_input, NULL, 2);
  static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, adt7411_show_input, NULL, 3);
  static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, adt7411_show_input, NULL, 4);
  static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, adt7411_show_input, NULL, 5);
  static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, adt7411_show_input, NULL, 6);
  static SENSOR_DEVICE_ATTR(in8_input, S_IRUGO, adt7411_show_input, NULL, 7);
  static ADT7411_BIT_ATTR(no_average, ADT7411_REG_CFG2, ADT7411_CFG2_DISABLE_AVG);
  static ADT7411_BIT_ATTR(fast_sampling, ADT7411_REG_CFG3, ADT7411_CFG3_ADC_CLK_225);
  static ADT7411_BIT_ATTR(adc_ref_vdd, ADT7411_REG_CFG3, ADT7411_CFG3_REF_VDD);
  
  static struct attribute *adt7411_attrs[] = {
  	&dev_attr_temp1_input.attr,
  	&dev_attr_in0_input.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,
  	&sensor_dev_attr_in5_input.dev_attr.attr,
  	&sensor_dev_attr_in6_input.dev_attr.attr,
  	&sensor_dev_attr_in7_input.dev_attr.attr,
  	&sensor_dev_attr_in8_input.dev_attr.attr,
  	&sensor_dev_attr_no_average.dev_attr.attr,
  	&sensor_dev_attr_fast_sampling.dev_attr.attr,
  	&sensor_dev_attr_adc_ref_vdd.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group adt7411_attr_grp = {
  	.attrs = adt7411_attrs,
  };
  
  static int adt7411_detect(struct i2c_client *client,
  			  struct i2c_board_info *info)
  {
  	int val;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;
  
  	val = i2c_smbus_read_byte_data(client, ADT7411_REG_MANUFACTURER_ID);
  	if (val < 0 || val != ADT7411_MANUFACTURER_ID) {
  		dev_dbg(&client->dev,
  			"Wrong manufacturer ID. Got %d, expected %d
  ",
  			val, ADT7411_MANUFACTURER_ID);
  		return -ENODEV;
  	}
  
  	val = i2c_smbus_read_byte_data(client, ADT7411_REG_DEVICE_ID);
  	if (val < 0 || val != ADT7411_DEVICE_ID) {
  		dev_dbg(&client->dev,
  			"Wrong device ID. Got %d, expected %d
  ",
  			val, ADT7411_DEVICE_ID);
  		return -ENODEV;
  	}
  
  	strlcpy(info->type, "adt7411", I2C_NAME_SIZE);
  
  	return 0;
  }
  
  static int adt7411_probe(struct i2c_client *client,
  				   const struct i2c_device_id *id)
  {
  	struct adt7411_data *data;
  	int ret;
  
  	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, data);
  	mutex_init(&data->device_lock);
  	mutex_init(&data->update_lock);
  
  	ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
  				 ADT7411_CFG1_START_MONITOR, 1);
  	if (ret < 0)
  		return ret;
  
  	/* force update on first occasion */
  	data->next_update = jiffies;
  
  	ret = sysfs_create_group(&client->dev.kobj, &adt7411_attr_grp);
  	if (ret)
  		return ret;
  
  	data->hwmon_dev = hwmon_device_register(&client->dev);
  	if (IS_ERR(data->hwmon_dev)) {
  		ret = PTR_ERR(data->hwmon_dev);
  		goto exit_remove;
  	}
  
  	dev_info(&client->dev, "successfully registered
  ");
  
  	return 0;
  
   exit_remove:
  	sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
  	return ret;
  }
  
  static int adt7411_remove(struct i2c_client *client)
  {
  	struct adt7411_data *data = i2c_get_clientdata(client);
  
  	hwmon_device_unregister(data->hwmon_dev);
  	sysfs_remove_group(&client->dev.kobj, &adt7411_attr_grp);
  	return 0;
  }
  
  static const struct i2c_device_id adt7411_id[] = {
  	{ "adt7411", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, adt7411_id);
  
  static struct i2c_driver adt7411_driver = {
  	.driver		= {
  		.name		= "adt7411",
  	},
  	.probe  = adt7411_probe,
  	.remove	= adt7411_remove,
  	.id_table = adt7411_id,
  	.detect = adt7411_detect,
  	.address_list = normal_i2c,
  	.class = I2C_CLASS_HWMON,
  };
  
  module_i2c_driver(adt7411_driver);
  
  MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de> and "
  	"Wolfram Sang <w.sang@pengutronix.de>");
  MODULE_DESCRIPTION("ADT7411 driver");
  MODULE_LICENSE("GPL v2");