Commit bc0a409c authored by Thierry Reding's avatar Thierry Reding Committed by Jonathan Cameron
Browse files

iio: adc: Add Texas Instruments ADC081C021/027 support 



Add support for reading conversion results from the ADC and provide them
through a single IIO channel. A proper scaling factor is also exported
based on the reference voltage provided by a regulator.

Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent fd1a8b91

drivers/iio/adc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -115,4 +115,14 @@ config MAX1363 
	  max11646, max11647) Provides direct access via sysfs and buffered

	  data via the iio dev interface.



config TI_ADC081C

	tristate "Texas Instruments ADC081C021/027"

	depends on I2C

	help

	  If you say yes here you get support for Texas Instruments ADC081C021

	  and ADC081C027 ADC chips.



	  This driver can also be built as a module. If so, the module will be

	  called ti-adc081c.



endmenu

drivers/iio/adc/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -12,3 +12,5 @@ obj-$(CONFIG_AD7887) += ad7887.o 
obj-$(CONFIG_AT91_ADC) += at91_adc.o

obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o

obj-$(CONFIG_MAX1363) += max1363.o

obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o

drivers/iio/adc/ti-adc081c.c

0 → 100644
+161 −0
Original line number Diff line number Diff line 
/*

 * 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/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 = IIO_CHAN_INFO_SCALE_SHARED_BIT |

		     IIO_CHAN_INFO_RAW_SEPARATE_BIT,

};



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 = iio_device_alloc(sizeof(*adc));

	if (!iio)

		return -ENOMEM;



	adc = iio_priv(iio);

	adc->i2c = client;



	adc->ref = regulator_get(&client->dev, "vref");

	if (IS_ERR(adc->ref)) {

		err = PTR_ERR(adc->ref);

		goto iio_free;

	}



	err = regulator_enable(adc->ref);

	if (err < 0)

		goto regulator_put;



	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);

regulator_put:

	regulator_put(adc->ref);

iio_free:

	iio_device_free(iio);



	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);

	regulator_put(adc->ref);

	iio_device_free(iio);



	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");