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kernel/linux-imx6_3.14.28/drivers/iio/adc/ti-adc081c.c 3.15 KB
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  /*
   * Copyright (C) 2012 Avionic Design GmbH
   *
   * 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.
   */
  
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/of.h>
  
  #include <linux/iio/iio.h>
  #include <linux/regulator/consumer.h>
  
  struct adc081c {
  	struct i2c_client *i2c;
  	struct regulator *ref;
  };
  
  #define REG_CONV_RES 0x00
  
  static int adc081c_read_raw(struct iio_dev *iio,
  			    struct iio_chan_spec const *channel, int *value,
  			    int *shift, long mask)
  {
  	struct adc081c *adc = iio_priv(iio);
  	int err;
  
  	switch (mask) {
  	case IIO_CHAN_INFO_RAW:
  		err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  		if (err < 0)
  			return err;
  
  		*value = (err >> 4) & 0xff;
  		return IIO_VAL_INT;
  
  	case IIO_CHAN_INFO_SCALE:
  		err = regulator_get_voltage(adc->ref);
  		if (err < 0)
  			return err;
  
  		*value = err / 1000;
  		*shift = 8;
  
  		return IIO_VAL_FRACTIONAL_LOG2;
  
  	default:
  		break;
  	}
  
  	return -EINVAL;
  }
  
  static const struct iio_chan_spec adc081c_channel = {
  	.type = IIO_VOLTAGE,
  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  };
  
  static const struct iio_info adc081c_info = {
  	.read_raw = adc081c_read_raw,
  	.driver_module = THIS_MODULE,
  };
  
  static int adc081c_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct iio_dev *iio;
  	struct adc081c *adc;
  	int err;
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
  		return -ENODEV;
  
  	iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
  	if (!iio)
  		return -ENOMEM;
  
  	adc = iio_priv(iio);
  	adc->i2c = client;
  
  	adc->ref = devm_regulator_get(&client->dev, "vref");
  	if (IS_ERR(adc->ref))
  		return PTR_ERR(adc->ref);
  
  	err = regulator_enable(adc->ref);
  	if (err < 0)
  		return err;
  
  	iio->dev.parent = &client->dev;
  	iio->name = dev_name(&client->dev);
  	iio->modes = INDIO_DIRECT_MODE;
  	iio->info = &adc081c_info;
  
  	iio->channels = &adc081c_channel;
  	iio->num_channels = 1;
  
  	err = iio_device_register(iio);
  	if (err < 0)
  		goto regulator_disable;
  
  	i2c_set_clientdata(client, iio);
  
  	return 0;
  
  regulator_disable:
  	regulator_disable(adc->ref);
  
  	return err;
  }
  
  static int adc081c_remove(struct i2c_client *client)
  {
  	struct iio_dev *iio = i2c_get_clientdata(client);
  	struct adc081c *adc = iio_priv(iio);
  
  	iio_device_unregister(iio);
  	regulator_disable(adc->ref);
  
  	return 0;
  }
  
  static const struct i2c_device_id adc081c_id[] = {
  	{ "adc081c", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, adc081c_id);
  
  #ifdef CONFIG_OF
  static const struct of_device_id adc081c_of_match[] = {
  	{ .compatible = "ti,adc081c" },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, adc081c_of_match);
  #endif
  
  static struct i2c_driver adc081c_driver = {
  	.driver = {
  		.name = "adc081c",
  		.owner = THIS_MODULE,
  		.of_match_table = of_match_ptr(adc081c_of_match),
  	},
  	.probe = adc081c_probe,
  	.remove = adc081c_remove,
  	.id_table = adc081c_id,
  };
  module_i2c_driver(adc081c_driver);
  
  MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
  MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
  MODULE_LICENSE("GPL v2");