/*
   * apds9802als.c - apds9802  ALS Driver
   *
   * Copyright (C) 2009 Intel Corp
   *
   *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * 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 of the License.
   *
   * 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.,
   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/i2c.h>
  #include <linux/err.h>
  #include <linux/delay.h>
  #include <linux/mutex.h>
  #include <linux/sysfs.h>
  #include <linux/pm_runtime.h>
  
  #define ALS_MIN_RANGE_VAL 1
  #define ALS_MAX_RANGE_VAL 2
  #define POWER_STA_ENABLE 1
  #define POWER_STA_DISABLE 0
  
  #define DRIVER_NAME "apds9802als"
  
  struct als_data {
  	struct mutex mutex;
  };
  
  static ssize_t als_sensing_range_show(struct device *dev,
  			struct device_attribute *attr,  char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	int  val;
  
  	val = i2c_smbus_read_byte_data(client, 0x81);
  	if (val < 0)
  		return val;
  	if (val & 1)
  		return sprintf(buf, "4095
  ");
  	else
  		return sprintf(buf, "65535
  ");
  }
  
  static int als_wait_for_data_ready(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	int ret;
  	int retry = 10;
  
  	do {
  		msleep(30);
  		ret = i2c_smbus_read_byte_data(client, 0x86);
  	} while (!(ret & 0x80) && retry--);
  
  	if (retry < 0) {
  		dev_warn(dev, "timeout waiting for data ready
  ");
  		return -ETIMEDOUT;
  	}
  
  	return 0;
  }
  
  static ssize_t als_lux0_input_data_show(struct device *dev,
  			struct device_attribute *attr, char *buf)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct als_data *data = i2c_get_clientdata(client);
  	int ret_val;
  	int temp;
  
  	/* Protect against parallel reads */
  	pm_runtime_get_sync(dev);
  	mutex_lock(&data->mutex);
  
  	/* clear EOC interrupt status */
  	i2c_smbus_write_byte(client, 0x40);
  	/* start measurement */
  	temp = i2c_smbus_read_byte_data(client, 0x81);
  	i2c_smbus_write_byte_data(client, 0x81, temp | 0x08);
  
  	ret_val = als_wait_for_data_ready(dev);
  	if (ret_val < 0)
  		goto failed;
  
  	temp = i2c_smbus_read_byte_data(client, 0x8C); /* LSB data */
  	if (temp < 0) {
  		ret_val = temp;
  		goto failed;
  	}
  	ret_val = i2c_smbus_read_byte_data(client, 0x8D); /* MSB data */
  	if (ret_val < 0)
  		goto failed;
  
  	mutex_unlock(&data->mutex);
  	pm_runtime_put_sync(dev);
  
  	temp = (ret_val << 8) | temp;
  	return sprintf(buf, "%d
  ", temp);
  failed:
  	mutex_unlock(&data->mutex);
  	pm_runtime_put_sync(dev);
  	return ret_val;
  }
  
  static ssize_t als_sensing_range_store(struct device *dev,
  		struct device_attribute *attr, const  char *buf, size_t count)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct als_data *data = i2c_get_clientdata(client);
  	int ret_val;
  	unsigned long val;
  
  	ret_val = kstrtoul(buf, 10, &val);
  	if (ret_val)
  		return ret_val;
  
  	if (val < 4096)
  		val = 1;
  	else if (val < 65536)
  		val = 2;
  	else
  		return -ERANGE;
  
  	pm_runtime_get_sync(dev);
  
  	/* Make sure nobody else reads/modifies/writes 0x81 while we
  	   are active */
  	mutex_lock(&data->mutex);
  
  	ret_val = i2c_smbus_read_byte_data(client, 0x81);
  	if (ret_val < 0)
  		goto fail;
  
  	/* Reset the bits before setting them */
  	ret_val = ret_val & 0xFA;
  
  	if (val == 1) /* Setting detection range up to 4k LUX */
  		ret_val = (ret_val | 0x01);
  	else /* Setting detection range up to 64k LUX*/
  		ret_val = (ret_val | 0x00);
  
  	ret_val = i2c_smbus_write_byte_data(client, 0x81, ret_val);
  
  	if (ret_val >= 0) {
  		/* All OK */
  		mutex_unlock(&data->mutex);
  		pm_runtime_put_sync(dev);
  		return count;
  	}
  fail:
  	mutex_unlock(&data->mutex);
  	pm_runtime_put_sync(dev);
  	return ret_val;
  }
  
  static int als_set_power_state(struct i2c_client *client, bool on_off)
  {
  	int ret_val;
  	struct als_data *data = i2c_get_clientdata(client);
  
  	mutex_lock(&data->mutex);
  	ret_val = i2c_smbus_read_byte_data(client, 0x80);
  	if (ret_val < 0)
  		goto fail;
  	if (on_off)
  		ret_val = ret_val | 0x01;
  	else
  		ret_val = ret_val & 0xFE;
  	ret_val = i2c_smbus_write_byte_data(client, 0x80, ret_val);
  fail:
  	mutex_unlock(&data->mutex);
  	return ret_val;
  }
  
  static DEVICE_ATTR(lux0_sensor_range, S_IRUGO | S_IWUSR,
  	als_sensing_range_show, als_sensing_range_store);
  static DEVICE_ATTR(lux0_input, S_IRUGO, als_lux0_input_data_show, NULL);
  
  static struct attribute *mid_att_als[] = {
  	&dev_attr_lux0_sensor_range.attr,
  	&dev_attr_lux0_input.attr,
  	NULL
  };
  
  static struct attribute_group m_als_gr = {
  	.name = "apds9802als",
  	.attrs = mid_att_als
  };
  
  static int als_set_default_config(struct i2c_client *client)
  {
  	int ret_val;
  	/* Write the command and then switch on */
  	ret_val = i2c_smbus_write_byte_data(client, 0x80, 0x01);
  	if (ret_val < 0) {
  		dev_err(&client->dev, "failed default switch on write
  ");
  		return ret_val;
  	}
  	/* detection range: 1~64K Lux, maunal measurement */
  	ret_val = i2c_smbus_write_byte_data(client, 0x81, 0x08);
  	if (ret_val < 0)
  		dev_err(&client->dev, "failed default LUX on write
  ");
  
  	/*  We always get 0 for the 1st measurement after system power on,
  	 *  so make sure it is finished before user asks for data.
  	 */
  	als_wait_for_data_ready(&client->dev);
  
  	return ret_val;
  }
  
  static int apds9802als_probe(struct i2c_client *client,
  			     const struct i2c_device_id *id)
  {
  	int res;
  	struct als_data *data;
  
  	data = kzalloc(sizeof(struct als_data), GFP_KERNEL);
  	if (data == NULL) {
  		dev_err(&client->dev, "Memory allocation failed
  ");
  		return -ENOMEM;
  	}
  	i2c_set_clientdata(client, data);
  	res = sysfs_create_group(&client->dev.kobj, &m_als_gr);
  	if (res) {
  		dev_err(&client->dev, "device create file failed
  ");
  		goto als_error1;
  	}
  	dev_info(&client->dev, "ALS chip found
  ");
  	als_set_default_config(client);
  	mutex_init(&data->mutex);
  
  	pm_runtime_set_active(&client->dev);
  	pm_runtime_enable(&client->dev);
  
  	return res;
  als_error1:
  	kfree(data);
  	return res;
  }
  
  static int apds9802als_remove(struct i2c_client *client)
  {
  	struct als_data *data = i2c_get_clientdata(client);
  
  	pm_runtime_get_sync(&client->dev);
  
  	als_set_power_state(client, false);
  	sysfs_remove_group(&client->dev.kobj, &m_als_gr);
  
  	pm_runtime_disable(&client->dev);
  	pm_runtime_set_suspended(&client->dev);
  	pm_runtime_put_noidle(&client->dev);
  
  	kfree(data);
  	return 0;
  }
  
  #ifdef CONFIG_PM
  
  static int apds9802als_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	als_set_power_state(client, false);
  	return 0;
  }
  
  static int apds9802als_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  
  	als_set_power_state(client, true);
  	return 0;
  }
  
  static UNIVERSAL_DEV_PM_OPS(apds9802als_pm_ops, apds9802als_suspend,
  	apds9802als_resume, NULL);
  
  #define APDS9802ALS_PM_OPS (&apds9802als_pm_ops)
  
  #else	/* CONFIG_PM */
  #define APDS9802ALS_PM_OPS NULL
  #endif	/* CONFIG_PM */
  
  static struct i2c_device_id apds9802als_id[] = {
  	{ DRIVER_NAME, 0 },
  	{ }
  };
  
  MODULE_DEVICE_TABLE(i2c, apds9802als_id);
  
  static struct i2c_driver apds9802als_driver = {
  	.driver = {
  		.name = DRIVER_NAME,
  		.pm = APDS9802ALS_PM_OPS,
  	},
  	.probe = apds9802als_probe,
  	.remove = apds9802als_remove,
  	.id_table = apds9802als_id,
  };
  
  module_i2c_driver(apds9802als_driver);
  
  MODULE_AUTHOR("Anantha Narayanan <Anantha.Narayanan@intel.com");
  MODULE_DESCRIPTION("Avago apds9802als ALS Driver");
  MODULE_LICENSE("GPL v2");