text: /*
   * tsl4531.c - Support for TAOS TSL4531 ambient light sensor
   *
   * Copyright 2013 Peter Meerwald <pmeerw@pmeerw.net>
   *
   * This file is subject to the terms and conditions of version 2 of
   * the GNU General Public License.  See the file COPYING in the main
   * directory of this archive for more details.
   *
   * IIO driver for the TSL4531x family
   *   TSL45311/TSL45313: 7-bit I2C slave address 0x39
   *   TSL45315/TSL45317: 7-bit I2C slave address 0x29
   *
   * TODO: single cycle measurement
   */
  
  #include <linux/module.h>
  #include <linux/i2c.h>
  #include <linux/err.h>
  #include <linux/delay.h>
  
  #include <linux/iio/iio.h>
  #include <linux/iio/sysfs.h>
  
  #define TSL4531_DRV_NAME "tsl4531"
  
  #define TSL4531_COMMAND BIT(7)
  
  #define TSL4531_CONTROL (TSL4531_COMMAND | 0x00)
  #define TSL4531_CONFIG (TSL4531_COMMAND | 0x01)
  #define TSL4531_DATA (TSL4531_COMMAND | 0x04)
  #define TSL4531_ID (TSL4531_COMMAND | 0x0a)
  
  /* operating modes in control register */
  #define TSL4531_MODE_POWERDOWN 0x00
  #define TSL4531_MODE_SINGLE_ADC 0x02
  #define TSL4531_MODE_NORMAL 0x03
  
  /* integration time control in config register */
  #define TSL4531_TCNTRL_400MS 0x00
  #define TSL4531_TCNTRL_200MS 0x01
  #define TSL4531_TCNTRL_100MS 0x02
  
  /* part number in id register */
  #define TSL45311_ID 0x8
  #define TSL45313_ID 0x9
  #define TSL45315_ID 0xa
  #define TSL45317_ID 0xb
  #define TSL4531_ID_SHIFT 4
  
  struct tsl4531_data {
  	struct i2c_client *client;
  	struct mutex lock;
  	int int_time;
  };
  
  static IIO_CONST_ATTR_INT_TIME_AVAIL("0.1 0.2 0.4");
  
  static struct attribute *tsl4531_attributes[] = {
  	&iio_const_attr_integration_time_available.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group tsl4531_attribute_group = {
  	.attrs = tsl4531_attributes,
  };
  
  static const struct iio_chan_spec tsl4531_channels[] = {
  	{
  		.type = IIO_LIGHT,
  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  			BIT(IIO_CHAN_INFO_SCALE) |
  			BIT(IIO_CHAN_INFO_INT_TIME)
  	}
  };
  
  static int tsl4531_read_raw(struct iio_dev *indio_dev,
  				struct iio_chan_spec const *chan,
  				int *val, int *val2, long mask)
  {
  	struct tsl4531_data *data = iio_priv(indio_dev);
  	int ret;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		ret = i2c_smbus_read_word_data(data->client,
  			TSL4531_DATA);
  		if (ret < 0)
  			return ret;
  		*val = ret;
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_SCALE:
  		/* 0.. 1x, 1 .. 2x, 2 .. 4x */
  		*val = 1 << data->int_time;
  		return IIO_VAL_INT;
  	case IIO_CHAN_INFO_INT_TIME:
  		if (data->int_time == 0)
  			*val2 = 400000;
  		else if (data->int_time == 1)
  			*val2 = 200000;
  		else if (data->int_time == 2)
  			*val2 = 100000;
  		else
  			return -EINVAL;
  		*val = 0;
  		return IIO_VAL_INT_PLUS_MICRO;
  	default:
  		return -EINVAL;
  	}
  }
  
  static int tsl4531_write_raw(struct iio_dev *indio_dev,
  			     struct iio_chan_spec const *chan,
  			     int val, int val2, long mask)
  {
  	struct tsl4531_data *data = iio_priv(indio_dev);
  	int int_time, ret;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_INT_TIME:
  		if (val != 0)
  			return -EINVAL;
  		if (val2 == 400000)
  			int_time = 0;
  		else if (val2 == 200000)
  			int_time = 1;
  		else if (val2 == 100000)
  			int_time = 2;
  		else
  			return -EINVAL;
  		mutex_lock(&data->lock);
  		ret = i2c_smbus_write_byte_data(data->client,
  			TSL4531_CONFIG, int_time);
  		if (ret >= 0)
  			data->int_time = int_time;
  		mutex_unlock(&data->lock);
  		return ret;
  	default:
  		return -EINVAL;
  	}
  }
  
  static const struct iio_info tsl4531_info = {
  	.read_raw = tsl4531_read_raw,
  	.write_raw = tsl4531_write_raw,
  	.attrs = &tsl4531_attribute_group,
  };
  
  static int tsl4531_check_id(struct i2c_client *client)
  {
  	int ret = i2c_smbus_read_byte_data(client, TSL4531_ID);
  	if (ret < 0)
  		return ret;
  
  	switch (ret >> TSL4531_ID_SHIFT) {
  	case TSL45311_ID:
  	case TSL45313_ID:
  	case TSL45315_ID:
  	case TSL45317_ID:
  		return 0;
  	default:
  		return -ENODEV;
  	}
  }
  
  static int tsl4531_probe(struct i2c_client *client,
  			  const struct i2c_device_id *id)
  {
  	struct tsl4531_data *data;
  	struct iio_dev *indio_dev;
  	int ret;
  
  	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
  	if (!indio_dev)
  		return -ENOMEM;
  
  	data = iio_priv(indio_dev);
  	i2c_set_clientdata(client, indio_dev);
  	data->client = client;
  	mutex_init(&data->lock);
  
  	ret = tsl4531_check_id(client);
  	if (ret) {
  		dev_err(&client->dev, "no TSL4531 sensor\n");
  		return ret;
  	}
  
  	ret = i2c_smbus_write_byte_data(data->client, TSL4531_CONTROL,
  		TSL4531_MODE_NORMAL);
  	if (ret < 0)
  		return ret;
  
  	ret = i2c_smbus_write_byte_data(data->client, TSL4531_CONFIG,
  		TSL4531_TCNTRL_400MS);
  	if (ret < 0)
  		return ret;
  
  	indio_dev->dev.parent = &client->dev;
  	indio_dev->info = &tsl4531_info;
  	indio_dev->channels = tsl4531_channels;
  	indio_dev->num_channels = ARRAY_SIZE(tsl4531_channels);
  	indio_dev->name = TSL4531_DRV_NAME;
  	indio_dev->modes = INDIO_DIRECT_MODE;
  
  	return iio_device_register(indio_dev);
  }
  
  static int tsl4531_powerdown(struct i2c_client *client)
  {
  	return i2c_smbus_write_byte_data(client, TSL4531_CONTROL,
  		TSL4531_MODE_POWERDOWN);
  }
  
  static int tsl4531_remove(struct i2c_client *client)
  {
  	iio_device_unregister(i2c_get_clientdata(client));
  	tsl4531_powerdown(client);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int tsl4531_suspend(struct device *dev)
  {
  	return tsl4531_powerdown(to_i2c_client(dev));
  }
  
  static int tsl4531_resume(struct device *dev)
  {
  	return i2c_smbus_write_byte_data(to_i2c_client(dev), TSL4531_CONTROL,
  		TSL4531_MODE_NORMAL);
  }
  
  static SIMPLE_DEV_PM_OPS(tsl4531_pm_ops, tsl4531_suspend, tsl4531_resume);
  #define TSL4531_PM_OPS (&tsl4531_pm_ops)
  #else
  #define TSL4531_PM_OPS NULL
  #endif
  
  static const struct i2c_device_id tsl4531_id[] = {
  	{ "tsl4531", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, tsl4531_id);
  
  static struct i2c_driver tsl4531_driver = {
  	.driver = {
  		.name   = TSL4531_DRV_NAME,
  		.pm	= TSL4531_PM_OPS,
  	},
  	.probe  = tsl4531_probe,
  	.remove = tsl4531_remove,
  	.id_table = tsl4531_id,
  };
  
  module_i2c_driver(tsl4531_driver);
  
  MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
  MODULE_DESCRIPTION("TAOS TSL4531 ambient light sensors driver");
  MODULE_LICENSE("GPL");
  