drivers/iio/adc/mcp320x.c - third_party/dump-capture-kernel - Git at Google

 /*
  * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
  * Copyright (C) 2014 Rose Technology
  * 	   Allan Bendorff Jensen <abj@rosetechnology.dk>
  *	   Soren Andersen <san@rosetechnology.dk>
  *
  * Driver for following ADC chips from Microchip Technology's:
  * 10 Bit converter
  * MCP3001
  * MCP3002
  * MCP3004
  * MCP3008
  * ------------
  * 12 bit converter
  * MCP3201
  * MCP3202
  * MCP3204
  * MCP3208
  * ------------
  * 13 bit converter
  * MCP3301
  *
  * Datasheet can be found here:
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
  * http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf  mcp3301
  *
  * 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/delay.h>
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/iio/iio.h>
 #include <linux/regulator/consumer.h>

 enum {
 	mcp3001,
 	mcp3002,
 	mcp3004,
 	mcp3008,
 	mcp3201,
 	mcp3202,
 	mcp3204,
 	mcp3208,
 	mcp3301,
 };

 struct mcp320x_chip_info {
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
 	unsigned int resolution;
 };

 struct mcp320x {
 	struct spi_device *spi;
 	struct spi_message msg;
 	struct spi_transfer transfer[2];

 	struct regulator *reg;
 	struct mutex lock;
 	const struct mcp320x_chip_info *chip_info;

 	u8 tx_buf ____cacheline_aligned;
 	u8 rx_buf[2];
 };

 static int mcp320x_channel_to_tx_data(int device_index,
 			const unsigned int channel, bool differential)
 {
 	int start_bit = 1;

 	switch (device_index) {
 	case mcp3001:
 	case mcp3201:
 	case mcp3301:
 		return 0;
 	case mcp3002:
 	case mcp3202:
 		return ((start_bit << 4) | (!differential << 3) |
 							(channel << 2));
 	case mcp3004:
 	case mcp3204:
 	case mcp3008:
 	case mcp3208:
 		return ((start_bit << 6) | (!differential << 5) |
 							(channel << 2));
 	default:
 		return -EINVAL;
 	}
 }

 static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
 				  bool differential, int device_index, int *val)
 {
 	int ret;

 	adc->rx_buf[0] = 0;
 	adc->rx_buf[1] = 0;
 	adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
 						channel, differential);

 	if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
 		ret = spi_sync(adc->spi, &adc->msg);
 		if (ret < 0)
 			return ret;
 	} else {
 		ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
 		if (ret < 0)
 			return ret;
 	}

 	switch (device_index) {
 	case mcp3001:
 		*val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
 		return 0;
 	case mcp3002:
 	case mcp3004:
 	case mcp3008:
 		*val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
 		return 0;
 	case mcp3201:
 		*val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
 		return 0;
 	case mcp3202:
 	case mcp3204:
 	case mcp3208:
 		*val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
 		return 0;
 	case mcp3301:
 		*val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
 				    | adc->rx_buf[1], 12);
 		return 0;
 	default:
 		return -EINVAL;
 	}
 }

 static int mcp320x_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *channel, int *val,
 			    int *val2, long mask)
 {
 	struct mcp320x *adc = iio_priv(indio_dev);
 	int ret = -EINVAL;
 	int device_index = 0;

 	mutex_lock(&adc->lock);

 	device_index = spi_get_device_id(adc->spi)->driver_data;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = mcp320x_adc_conversion(adc, channel->address,
 			channel->differential, device_index, val);
 		if (ret < 0)
 			goto out;

 		ret = IIO_VAL_INT;
 		break;

 	case IIO_CHAN_INFO_SCALE:
 		ret = regulator_get_voltage(adc->reg);
 		if (ret < 0)
 			goto out;

 		/* convert regulator output voltage to mV */
 		*val = ret / 1000;
 		*val2 = adc->chip_info->resolution;
 		ret = IIO_VAL_FRACTIONAL_LOG2;
 		break;
 	}

 out:
 	mutex_unlock(&adc->lock);

 	return ret;
 }

 #define MCP320X_VOLTAGE_CHANNEL(num)				\
 	{							\
 		.type = IIO_VOLTAGE,				\
 		.indexed = 1,					\
 		.channel = (num),				\
 		.address = (num),				\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 	}

 #define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2)		\
 	{							\
 		.type = IIO_VOLTAGE,				\
 		.indexed = 1,					\
 		.channel = (chan1),				\
 		.channel2 = (chan2),				\
 		.address = (chan1),				\
 		.differential = 1,				\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
 	}

 static const struct iio_chan_spec mcp3201_channels[] = {
 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
 };

 static const struct iio_chan_spec mcp3202_channels[] = {
 	MCP320X_VOLTAGE_CHANNEL(0),
 	MCP320X_VOLTAGE_CHANNEL(1),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
 };

 static const struct iio_chan_spec mcp3204_channels[] = {
 	MCP320X_VOLTAGE_CHANNEL(0),
 	MCP320X_VOLTAGE_CHANNEL(1),
 	MCP320X_VOLTAGE_CHANNEL(2),
 	MCP320X_VOLTAGE_CHANNEL(3),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
 };

 static const struct iio_chan_spec mcp3208_channels[] = {
 	MCP320X_VOLTAGE_CHANNEL(0),
 	MCP320X_VOLTAGE_CHANNEL(1),
 	MCP320X_VOLTAGE_CHANNEL(2),
 	MCP320X_VOLTAGE_CHANNEL(3),
 	MCP320X_VOLTAGE_CHANNEL(4),
 	MCP320X_VOLTAGE_CHANNEL(5),
 	MCP320X_VOLTAGE_CHANNEL(6),
 	MCP320X_VOLTAGE_CHANNEL(7),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
 	MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
 };

 static const struct iio_info mcp320x_info = {
 	.read_raw = mcp320x_read_raw,
 	.driver_module = THIS_MODULE,
 };

 static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
 	[mcp3001] = {
 		.channels = mcp3201_channels,
 		.num_channels = ARRAY_SIZE(mcp3201_channels),
 		.resolution = 10
 	},
 	[mcp3002] = {
 		.channels = mcp3202_channels,
 		.num_channels = ARRAY_SIZE(mcp3202_channels),
 		.resolution = 10
 	},
 	[mcp3004] = {
 		.channels = mcp3204_channels,
 		.num_channels = ARRAY_SIZE(mcp3204_channels),
 		.resolution = 10
 	},
 	[mcp3008] = {
 		.channels = mcp3208_channels,
 		.num_channels = ARRAY_SIZE(mcp3208_channels),
 		.resolution = 10
 	},
 	[mcp3201] = {
 		.channels = mcp3201_channels,
 		.num_channels = ARRAY_SIZE(mcp3201_channels),
 		.resolution = 12
 	},
 	[mcp3202] = {
 		.channels = mcp3202_channels,
 		.num_channels = ARRAY_SIZE(mcp3202_channels),
 		.resolution = 12
 	},
 	[mcp3204] = {
 		.channels = mcp3204_channels,
 		.num_channels = ARRAY_SIZE(mcp3204_channels),
 		.resolution = 12
 	},
 	[mcp3208] = {
 		.channels = mcp3208_channels,
 		.num_channels = ARRAY_SIZE(mcp3208_channels),
 		.resolution = 12
 	},
 	[mcp3301] = {
 		.channels = mcp3201_channels,
 		.num_channels = ARRAY_SIZE(mcp3201_channels),
 		.resolution = 13
 	},
 };

 static int mcp320x_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
 	struct mcp320x *adc;
 	const struct mcp320x_chip_info *chip_info;
 	int ret;

 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 	if (!indio_dev)
 		return -ENOMEM;

 	adc = iio_priv(indio_dev);
 	adc->spi = spi;

 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->dev.of_node = spi->dev.of_node;
 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &mcp320x_info;
 	spi_set_drvdata(spi, indio_dev);

 	chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
 	indio_dev->channels = chip_info->channels;
 	indio_dev->num_channels = chip_info->num_channels;

 	adc->chip_info = chip_info;

 	adc->transfer[0].tx_buf = &adc->tx_buf;
 	adc->transfer[0].len = sizeof(adc->tx_buf);
 	adc->transfer[1].rx_buf = adc->rx_buf;
 	adc->transfer[1].len = sizeof(adc->rx_buf);

 	spi_message_init_with_transfers(&adc->msg, adc->transfer,
 					ARRAY_SIZE(adc->transfer));

 	adc->reg = devm_regulator_get(&spi->dev, "vref");
 	if (IS_ERR(adc->reg))
 		return PTR_ERR(adc->reg);

 	ret = regulator_enable(adc->reg);
 	if (ret < 0)
 		return ret;

 	mutex_init(&adc->lock);

 	ret = iio_device_register(indio_dev);
 	if (ret < 0)
 		goto reg_disable;

 	return 0;

 reg_disable:
 	regulator_disable(adc->reg);

 	return ret;
 }

 static int mcp320x_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct mcp320x *adc = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	regulator_disable(adc->reg);

 	return 0;
 }

 #if defined(CONFIG_OF)
 static const struct of_device_id mcp320x_dt_ids[] = {
 	/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
 	{
 		.compatible = "mcp3001",
 		.data = &mcp320x_chip_infos[mcp3001],
 	}, {
 		.compatible = "mcp3002",
 		.data = &mcp320x_chip_infos[mcp3002],
 	}, {
 		.compatible = "mcp3004",
 		.data = &mcp320x_chip_infos[mcp3004],
 	}, {
 		.compatible = "mcp3008",
 		.data = &mcp320x_chip_infos[mcp3008],
 	}, {
 		.compatible = "mcp3201",
 		.data = &mcp320x_chip_infos[mcp3201],
 	}, {
 		.compatible = "mcp3202",
 		.data = &mcp320x_chip_infos[mcp3202],
 	}, {
 		.compatible = "mcp3204",
 		.data = &mcp320x_chip_infos[mcp3204],
 	}, {
 		.compatible = "mcp3208",
 		.data = &mcp320x_chip_infos[mcp3208],
 	}, {
 		.compatible = "mcp3301",
 		.data = &mcp320x_chip_infos[mcp3301],
 	}, {
 		.compatible = "microchip,mcp3001",
 		.data = &mcp320x_chip_infos[mcp3001],
 	}, {
 		.compatible = "microchip,mcp3002",
 		.data = &mcp320x_chip_infos[mcp3002],
 	}, {
 		.compatible = "microchip,mcp3004",
 		.data = &mcp320x_chip_infos[mcp3004],
 	}, {
 		.compatible = "microchip,mcp3008",
 		.data = &mcp320x_chip_infos[mcp3008],
 	}, {
 		.compatible = "microchip,mcp3201",
 		.data = &mcp320x_chip_infos[mcp3201],
 	}, {
 		.compatible = "microchip,mcp3202",
 		.data = &mcp320x_chip_infos[mcp3202],
 	}, {
 		.compatible = "microchip,mcp3204",
 		.data = &mcp320x_chip_infos[mcp3204],
 	}, {
 		.compatible = "microchip,mcp3208",
 		.data = &mcp320x_chip_infos[mcp3208],
 	}, {
 		.compatible = "microchip,mcp3301",
 		.data = &mcp320x_chip_infos[mcp3301],
 	}, {
 	}
 };
 MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
 #endif

 static const struct spi_device_id mcp320x_id[] = {
 	{ "mcp3001", mcp3001 },
 	{ "mcp3002", mcp3002 },
 	{ "mcp3004", mcp3004 },
 	{ "mcp3008", mcp3008 },
 	{ "mcp3201", mcp3201 },
 	{ "mcp3202", mcp3202 },
 	{ "mcp3204", mcp3204 },
 	{ "mcp3208", mcp3208 },
 	{ "mcp3301", mcp3301 },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, mcp320x_id);

 static struct spi_driver mcp320x_driver = {
 	.driver = {
 		.name = "mcp320x",
 		.of_match_table = of_match_ptr(mcp320x_dt_ids),
 	},
 	.probe = mcp320x_probe,
 	.remove = mcp320x_remove,
 	.id_table = mcp320x_id,
 };
 module_spi_driver(mcp320x_driver);

 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
 MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
	* Copyright (C) 2014 Rose Technology
	* Allan Bendorff Jensen <abj@rosetechnology.dk>
	* Soren Andersen <san@rosetechnology.dk>
	*
	* Driver for following ADC chips from Microchip Technology's:
	* 10 Bit converter
	* MCP3001
	* MCP3002
	* MCP3004
	* MCP3008
	* ------------
	* 12 bit converter
	* MCP3201
	* MCP3202
	* MCP3204
	* MCP3208
	* ------------
	* 13 bit converter
	* MCP3301
	*
	* Datasheet can be found here:
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
	* http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
	*
	* 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/delay.h>
	#include <linux/spi/spi.h>
	#include <linux/module.h>
	#include <linux/iio/iio.h>
	#include <linux/regulator/consumer.h>

	enum {
	mcp3001,
	mcp3002,
	mcp3004,
	mcp3008,
	mcp3201,
	mcp3202,
	mcp3204,
	mcp3208,
	mcp3301,
	};

	struct mcp320x_chip_info {
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	unsigned int resolution;
	};

	struct mcp320x {
	struct spi_device *spi;
	struct spi_message msg;
	struct spi_transfer transfer[2];

	struct regulator *reg;
	struct mutex lock;
	const struct mcp320x_chip_info *chip_info;

	u8 tx_buf ____cacheline_aligned;
	u8 rx_buf[2];
	};

	static int mcp320x_channel_to_tx_data(int device_index,
	const unsigned int channel, bool differential)
	{
	int start_bit = 1;

	switch (device_index) {
	case mcp3001:
	case mcp3201:
	case mcp3301:
	return 0;
	case mcp3002:
	case mcp3202:
	return ((start_bit << 4) \| (!differential << 3) \|
	(channel << 2));
	case mcp3004:
	case mcp3204:
	case mcp3008:
	case mcp3208:
	return ((start_bit << 6) \| (!differential << 5) \|
	(channel << 2));
	default:
	return -EINVAL;
	}
	}

	static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
	bool differential, int device_index, int *val)
	{
	int ret;

	adc->rx_buf[0] = 0;
	adc->rx_buf[1] = 0;
	adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
	channel, differential);

	if (device_index != mcp3001 && device_index != mcp3201 && device_index != mcp3301) {
	ret = spi_sync(adc->spi, &adc->msg);
	if (ret < 0)
	return ret;
	} else {
	ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
	if (ret < 0)
	return ret;
	}

	switch (device_index) {
	case mcp3001:
	*val = (adc->rx_buf[0] << 5 \| adc->rx_buf[1] >> 3);
	return 0;
	case mcp3002:
	case mcp3004:
	case mcp3008:
	*val = (adc->rx_buf[0] << 2 \| adc->rx_buf[1] >> 6);
	return 0;
	case mcp3201:
	*val = (adc->rx_buf[0] << 7 \| adc->rx_buf[1] >> 1);
	return 0;
	case mcp3202:
	case mcp3204:
	case mcp3208:
	*val = (adc->rx_buf[0] << 4 \| adc->rx_buf[1] >> 4);
	return 0;
	case mcp3301:
	*val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
	\| adc->rx_buf[1], 12);
	return 0;
	default:
	return -EINVAL;
	}
	}

	static int mcp320x_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const channel, int val,
	int *val2, long mask)
	{
	struct mcp320x *adc = iio_priv(indio_dev);
	int ret = -EINVAL;
	int device_index = 0;

	mutex_lock(&adc->lock);

	device_index = spi_get_device_id(adc->spi)->driver_data;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = mcp320x_adc_conversion(adc, channel->address,
	channel->differential, device_index, val);
	if (ret < 0)
	goto out;

	ret = IIO_VAL_INT;
	break;

	case IIO_CHAN_INFO_SCALE:
	ret = regulator_get_voltage(adc->reg);
	if (ret < 0)
	goto out;

	/* convert regulator output voltage to mV */
	*val = ret / 1000;
	*val2 = adc->chip_info->resolution;
	ret = IIO_VAL_FRACTIONAL_LOG2;
	break;
	}

	out:
	mutex_unlock(&adc->lock);

	return ret;
	}

	#define MCP320X_VOLTAGE_CHANNEL(num) \
	{ \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (num), \
	.address = (num), \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
	}

	#define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
	{ \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (chan1), \
	.channel2 = (chan2), \
	.address = (chan1), \
	.differential = 1, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
	}

	static const struct iio_chan_spec mcp3201_channels[] = {
	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
	};

	static const struct iio_chan_spec mcp3202_channels[] = {
	MCP320X_VOLTAGE_CHANNEL(0),
	MCP320X_VOLTAGE_CHANNEL(1),
	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
	};

	static const struct iio_chan_spec mcp3204_channels[] = {
	MCP320X_VOLTAGE_CHANNEL(0),
	MCP320X_VOLTAGE_CHANNEL(1),
	MCP320X_VOLTAGE_CHANNEL(2),
	MCP320X_VOLTAGE_CHANNEL(3),
	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
	};

	static const struct iio_chan_spec mcp3208_channels[] = {
	MCP320X_VOLTAGE_CHANNEL(0),
	MCP320X_VOLTAGE_CHANNEL(1),
	MCP320X_VOLTAGE_CHANNEL(2),
	MCP320X_VOLTAGE_CHANNEL(3),
	MCP320X_VOLTAGE_CHANNEL(4),
	MCP320X_VOLTAGE_CHANNEL(5),
	MCP320X_VOLTAGE_CHANNEL(6),
	MCP320X_VOLTAGE_CHANNEL(7),
	MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
	MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
	MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
	MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
	MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
	MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
	MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
	MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
	};

	static const struct iio_info mcp320x_info = {
	.read_raw = mcp320x_read_raw,
	.driver_module = THIS_MODULE,
	};

	static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
	[mcp3001] = {
	.channels = mcp3201_channels,
	.num_channels = ARRAY_SIZE(mcp3201_channels),
	.resolution = 10
	},
	[mcp3002] = {
	.channels = mcp3202_channels,
	.num_channels = ARRAY_SIZE(mcp3202_channels),
	.resolution = 10
	},
	[mcp3004] = {
	.channels = mcp3204_channels,
	.num_channels = ARRAY_SIZE(mcp3204_channels),
	.resolution = 10
	},
	[mcp3008] = {
	.channels = mcp3208_channels,
	.num_channels = ARRAY_SIZE(mcp3208_channels),
	.resolution = 10
	},
	[mcp3201] = {
	.channels = mcp3201_channels,
	.num_channels = ARRAY_SIZE(mcp3201_channels),
	.resolution = 12
	},
	[mcp3202] = {
	.channels = mcp3202_channels,
	.num_channels = ARRAY_SIZE(mcp3202_channels),
	.resolution = 12
	},
	[mcp3204] = {
	.channels = mcp3204_channels,
	.num_channels = ARRAY_SIZE(mcp3204_channels),
	.resolution = 12
	},
	[mcp3208] = {
	.channels = mcp3208_channels,
	.num_channels = ARRAY_SIZE(mcp3208_channels),
	.resolution = 12
	},
	[mcp3301] = {
	.channels = mcp3201_channels,
	.num_channels = ARRAY_SIZE(mcp3201_channels),
	.resolution = 13
	},
	};

	static int mcp320x_probe(struct spi_device *spi)
	{
	struct iio_dev *indio_dev;
	struct mcp320x *adc;
	const struct mcp320x_chip_info *chip_info;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
	if (!indio_dev)
	return -ENOMEM;

	adc = iio_priv(indio_dev);
	adc->spi = spi;

	indio_dev->dev.parent = &spi->dev;
	indio_dev->dev.of_node = spi->dev.of_node;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &mcp320x_info;
	spi_set_drvdata(spi, indio_dev);

	chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
	indio_dev->channels = chip_info->channels;
	indio_dev->num_channels = chip_info->num_channels;

	adc->chip_info = chip_info;

	adc->transfer[0].tx_buf = &adc->tx_buf;
	adc->transfer[0].len = sizeof(adc->tx_buf);
	adc->transfer[1].rx_buf = adc->rx_buf;
	adc->transfer[1].len = sizeof(adc->rx_buf);

	spi_message_init_with_transfers(&adc->msg, adc->transfer,
	ARRAY_SIZE(adc->transfer));

	adc->reg = devm_regulator_get(&spi->dev, "vref");
	if (IS_ERR(adc->reg))
	return PTR_ERR(adc->reg);

	ret = regulator_enable(adc->reg);
	if (ret < 0)
	return ret;

	mutex_init(&adc->lock);

	ret = iio_device_register(indio_dev);
	if (ret < 0)
	goto reg_disable;

	return 0;

	reg_disable:
	regulator_disable(adc->reg);

	return ret;
	}

	static int mcp320x_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct mcp320x *adc = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	regulator_disable(adc->reg);

	return 0;
	}

	#if defined(CONFIG_OF)
	static const struct of_device_id mcp320x_dt_ids[] = {
	/* NOTE: The use of compatibles with no vendor prefix is deprecated. */
	{
	.compatible = "mcp3001",
	.data = &mcp320x_chip_infos[mcp3001],
	}, {
	.compatible = "mcp3002",
	.data = &mcp320x_chip_infos[mcp3002],
	}, {
	.compatible = "mcp3004",
	.data = &mcp320x_chip_infos[mcp3004],
	}, {
	.compatible = "mcp3008",
	.data = &mcp320x_chip_infos[mcp3008],
	}, {
	.compatible = "mcp3201",
	.data = &mcp320x_chip_infos[mcp3201],
	}, {
	.compatible = "mcp3202",
	.data = &mcp320x_chip_infos[mcp3202],
	}, {
	.compatible = "mcp3204",
	.data = &mcp320x_chip_infos[mcp3204],
	}, {
	.compatible = "mcp3208",
	.data = &mcp320x_chip_infos[mcp3208],
	}, {
	.compatible = "mcp3301",
	.data = &mcp320x_chip_infos[mcp3301],
	}, {
	.compatible = "microchip,mcp3001",
	.data = &mcp320x_chip_infos[mcp3001],
	}, {
	.compatible = "microchip,mcp3002",
	.data = &mcp320x_chip_infos[mcp3002],
	}, {
	.compatible = "microchip,mcp3004",
	.data = &mcp320x_chip_infos[mcp3004],
	}, {
	.compatible = "microchip,mcp3008",
	.data = &mcp320x_chip_infos[mcp3008],
	}, {
	.compatible = "microchip,mcp3201",
	.data = &mcp320x_chip_infos[mcp3201],
	}, {
	.compatible = "microchip,mcp3202",
	.data = &mcp320x_chip_infos[mcp3202],
	}, {
	.compatible = "microchip,mcp3204",
	.data = &mcp320x_chip_infos[mcp3204],
	}, {
	.compatible = "microchip,mcp3208",
	.data = &mcp320x_chip_infos[mcp3208],
	}, {
	.compatible = "microchip,mcp3301",
	.data = &mcp320x_chip_infos[mcp3301],
	}, {
	}
	};
	MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
	#endif

	static const struct spi_device_id mcp320x_id[] = {
	{ "mcp3001", mcp3001 },
	{ "mcp3002", mcp3002 },
	{ "mcp3004", mcp3004 },
	{ "mcp3008", mcp3008 },
	{ "mcp3201", mcp3201 },
	{ "mcp3202", mcp3202 },
	{ "mcp3204", mcp3204 },
	{ "mcp3208", mcp3208 },
	{ "mcp3301", mcp3301 },
	{ }
	};
	MODULE_DEVICE_TABLE(spi, mcp320x_id);

	static struct spi_driver mcp320x_driver = {
	.driver = {
	.name = "mcp320x",
	.of_match_table = of_match_ptr(mcp320x_dt_ids),
	},
	.probe = mcp320x_probe,
	.remove = mcp320x_remove,
	.id_table = mcp320x_id,
	};
	module_spi_driver(mcp320x_driver);

	MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
	MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
	MODULE_LICENSE("GPL v2");