drivers/iio/adc/ti-adc084s021.c - third_party/linux - Git at Google

 /**
  * Copyright (C) 2017 Axis Communications AB
  *
  * Driver for Texas Instruments' ADC084S021 ADC chip.
  * Datasheets can be found here:
  * http://www.ti.com/lit/ds/symlink/adc084s021.pdf
  *
  * 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/spi/spi.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/regulator/consumer.h>

 #define ADC084S021_DRIVER_NAME "adc084s021"

 struct adc084s021 {
 	struct spi_device *spi;
 	struct spi_message message;
 	struct spi_transfer spi_trans;
 	struct regulator *reg;
 	struct mutex lock;
 	/* Buffer used to align data */
 	struct {
 		__be16 channels[4];
 		s64 ts __aligned(8);
 	} scan;
 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache line.
 	 */
 	u16 tx_buf[4] ____cacheline_aligned;
 	__be16 rx_buf[5]; /* First 16-bits are trash */
 };

 #define ADC084S021_VOLTAGE_CHANNEL(num)                  \
 	{                                                      \
 		.type = IIO_VOLTAGE,                                 \
 		.channel = (num),                                    \
 		.indexed = 1,                                        \
 		.scan_index = (num),                                 \
 		.scan_type = {                                       \
 			.sign = 'u',                                       \
 			.realbits = 8,                                     \
 			.storagebits = 16,                                 \
 			.shift = 4,                                        \
 			.endianness = IIO_BE,                              \
 		},                                                   \
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),        \
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
 	}

 static const struct iio_chan_spec adc084s021_channels[] = {
 	ADC084S021_VOLTAGE_CHANNEL(0),
 	ADC084S021_VOLTAGE_CHANNEL(1),
 	ADC084S021_VOLTAGE_CHANNEL(2),
 	ADC084S021_VOLTAGE_CHANNEL(3),
 	IIO_CHAN_SOFT_TIMESTAMP(4),
 };

 /**
  * Read an ADC channel and return its value.
  *
  * @adc: The ADC SPI data.
  * @data: Buffer for converted data.
  */
 static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
 {
 	int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
 	int ret, i = 0;
 	u16 *p = data;

 	/* Do the transfer */
 	ret = spi_sync(adc->spi, &adc->message);
 	if (ret < 0)
 		return ret;

 	for (; i < n_words; i++)
 		*(p + i) = adc->rx_buf[i + 1];

 	return ret;
 }

 static int adc084s021_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *channel, int *val,
 			   int *val2, long mask)
 {
 	struct adc084s021 *adc = iio_priv(indio_dev);
 	int ret;

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		ret = iio_device_claim_direct_mode(indio_dev);
 		if (ret < 0)
 			return ret;

 		ret = regulator_enable(adc->reg);
 		if (ret) {
 			iio_device_release_direct_mode(indio_dev);
 			return ret;
 		}

 		adc->tx_buf[0] = channel->channel << 3;
 		ret = adc084s021_adc_conversion(adc, val);
 		iio_device_release_direct_mode(indio_dev);
 		regulator_disable(adc->reg);
 		if (ret < 0)
 			return ret;

 		*val = be16_to_cpu(*val);
 		*val = (*val >> channel->scan_type.shift) & 0xff;

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		ret = regulator_enable(adc->reg);
 		if (ret)
 			return ret;

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

 		*val = ret / 1000;

 		return IIO_VAL_INT;
 	default:
 		return -EINVAL;
 	}
 }

 /**
  * Read enabled ADC channels and push data to the buffer.
  *
  * @irq: The interrupt number (not used).
  * @pollfunc: Pointer to the poll func.
  */
 static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
 {
 	struct iio_poll_func *pf = pollfunc;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adc084s021 *adc = iio_priv(indio_dev);

 	mutex_lock(&adc->lock);

 	if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0)
 		dev_err(&adc->spi->dev, "Failed to read data\n");

 	iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
 					   iio_get_time_ns(indio_dev));
 	mutex_unlock(&adc->lock);
 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
 {
 	struct adc084s021 *adc = iio_priv(indio_dev);
 	int scan_index;
 	int i = 0;

 	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 			 indio_dev->masklength) {
 		const struct iio_chan_spec *channel =
 			&indio_dev->channels[scan_index];
 		adc->tx_buf[i++] = channel->channel << 3;
 	}
 	adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */

 	return regulator_enable(adc->reg);
 }

 static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
 {
 	struct adc084s021 *adc = iio_priv(indio_dev);

 	adc->spi_trans.len = 4; /* Trash + single channel */

 	return regulator_disable(adc->reg);
 }

 static const struct iio_info adc084s021_info = {
 	.read_raw = adc084s021_read_raw,
 };

 static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
 	.preenable = adc084s021_buffer_preenable,
 	.postenable = iio_triggered_buffer_postenable,
 	.predisable = iio_triggered_buffer_predisable,
 	.postdisable = adc084s021_buffer_postdisable,
 };

 static int adc084s021_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
 	struct adc084s021 *adc;
 	int ret;

 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 	if (!indio_dev) {
 		dev_err(&spi->dev, "Failed to allocate IIO device\n");
 		return -ENOMEM;
 	}

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

 	/* Connect the SPI device and the iio dev */
 	spi_set_drvdata(spi, indio_dev);

 	/* Initiate the Industrial I/O device */
 	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 = &adc084s021_info;
 	indio_dev->channels = adc084s021_channels;
 	indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);

 	/* Create SPI transfer for channel reads */
 	adc->spi_trans.tx_buf = adc->tx_buf;
 	adc->spi_trans.rx_buf = adc->rx_buf;
 	adc->spi_trans.len = 4; /* Trash + single channel */
 	spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);

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

 	mutex_init(&adc->lock);

 	/* Setup triggered buffer with pollfunction */
 	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
 					    adc084s021_buffer_trigger_handler,
 					    &adc084s021_buffer_setup_ops);
 	if (ret) {
 		dev_err(&spi->dev, "Failed to setup triggered buffer\n");
 		return ret;
 	}

 	return devm_iio_device_register(&spi->dev, indio_dev);
 }

 static const struct of_device_id adc084s021_of_match[] = {
 	{ .compatible = "ti,adc084s021", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, adc084s021_of_match);

 static const struct spi_device_id adc084s021_id[] = {
 	{ ADC084S021_DRIVER_NAME, 0},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, adc084s021_id);

 static struct spi_driver adc084s021_driver = {
 	.driver = {
 		.name = ADC084S021_DRIVER_NAME,
 		.of_match_table = of_match_ptr(adc084s021_of_match),
 	},
 	.probe = adc084s021_probe,
 	.id_table = adc084s021_id,
 };
 module_spi_driver(adc084s021_driver);

 MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
 MODULE_DESCRIPTION("Texas Instruments ADC084S021");
 MODULE_LICENSE("GPL v2");
 MODULE_VERSION("1.0");
	/**
	* Copyright (C) 2017 Axis Communications AB
	*
	* Driver for Texas Instruments' ADC084S021 ADC chip.
	* Datasheets can be found here:
	* http://www.ti.com/lit/ds/symlink/adc084s021.pdf
	*
	* 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/spi/spi.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/triggered_buffer.h>
	#include <linux/iio/trigger_consumer.h>
	#include <linux/regulator/consumer.h>

	#define ADC084S021_DRIVER_NAME "adc084s021"

	struct adc084s021 {
	struct spi_device *spi;
	struct spi_message message;
	struct spi_transfer spi_trans;
	struct regulator *reg;
	struct mutex lock;
	/* Buffer used to align data */
	struct {
	__be16 channels[4];
	s64 ts __aligned(8);
	} scan;
	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache line.
	*/
	u16 tx_buf[4] ____cacheline_aligned;
	__be16 rx_buf[5]; /* First 16-bits are trash */
	};

	#define ADC084S021_VOLTAGE_CHANNEL(num) \
	{ \
	.type = IIO_VOLTAGE, \
	.channel = (num), \
	.indexed = 1, \
	.scan_index = (num), \
	.scan_type = { \
	.sign = 'u', \
	.realbits = 8, \
	.storagebits = 16, \
	.shift = 4, \
	.endianness = IIO_BE, \
	}, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
	}

	static const struct iio_chan_spec adc084s021_channels[] = {
	ADC084S021_VOLTAGE_CHANNEL(0),
	ADC084S021_VOLTAGE_CHANNEL(1),
	ADC084S021_VOLTAGE_CHANNEL(2),
	ADC084S021_VOLTAGE_CHANNEL(3),
	IIO_CHAN_SOFT_TIMESTAMP(4),
	};

	/**
	* Read an ADC channel and return its value.
	*
	* @adc: The ADC SPI data.
	* @data: Buffer for converted data.
	*/
	static int adc084s021_adc_conversion(struct adc084s021 adc, void data)
	{
	int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
	int ret, i = 0;
	u16 *p = data;

	/* Do the transfer */
	ret = spi_sync(adc->spi, &adc->message);
	if (ret < 0)
	return ret;

	for (; i < n_words; i++)
	*(p + i) = adc->rx_buf[i + 1];

	return ret;
	}

	static int adc084s021_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const channel, int val,
	int *val2, long mask)
	{
	struct adc084s021 *adc = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret < 0)
	return ret;

	ret = regulator_enable(adc->reg);
	if (ret) {
	iio_device_release_direct_mode(indio_dev);
	return ret;
	}

	adc->tx_buf[0] = channel->channel << 3;
	ret = adc084s021_adc_conversion(adc, val);
	iio_device_release_direct_mode(indio_dev);
	regulator_disable(adc->reg);
	if (ret < 0)
	return ret;

	val = be16_to_cpu(val);
	val = (val >> channel->scan_type.shift) & 0xff;

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	ret = regulator_enable(adc->reg);
	if (ret)
	return ret;

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

	*val = ret / 1000;

	return IIO_VAL_INT;
	default:
	return -EINVAL;
	}
	}

	/**
	* Read enabled ADC channels and push data to the buffer.
	*
	* @irq: The interrupt number (not used).
	* @pollfunc: Pointer to the poll func.
	*/
	static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
	{
	struct iio_poll_func *pf = pollfunc;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct adc084s021 *adc = iio_priv(indio_dev);

	mutex_lock(&adc->lock);

	if (adc084s021_adc_conversion(adc, adc->scan.channels) < 0)
	dev_err(&adc->spi->dev, "Failed to read data\n");

	iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
	iio_get_time_ns(indio_dev));
	mutex_unlock(&adc->lock);
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
	{
	struct adc084s021 *adc = iio_priv(indio_dev);
	int scan_index;
	int i = 0;

	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
	indio_dev->masklength) {
	const struct iio_chan_spec *channel =
	&indio_dev->channels[scan_index];
	adc->tx_buf[i++] = channel->channel << 3;
	}
	adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */

	return regulator_enable(adc->reg);
	}

	static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
	{
	struct adc084s021 *adc = iio_priv(indio_dev);

	adc->spi_trans.len = 4; /* Trash + single channel */

	return regulator_disable(adc->reg);
	}

	static const struct iio_info adc084s021_info = {
	.read_raw = adc084s021_read_raw,
	};

	static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
	.preenable = adc084s021_buffer_preenable,
	.postenable = iio_triggered_buffer_postenable,
	.predisable = iio_triggered_buffer_predisable,
	.postdisable = adc084s021_buffer_postdisable,
	};

	static int adc084s021_probe(struct spi_device *spi)
	{
	struct iio_dev *indio_dev;
	struct adc084s021 *adc;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
	if (!indio_dev) {
	dev_err(&spi->dev, "Failed to allocate IIO device\n");
	return -ENOMEM;
	}

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

	/* Connect the SPI device and the iio dev */
	spi_set_drvdata(spi, indio_dev);

	/* Initiate the Industrial I/O device */
	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 = &adc084s021_info;
	indio_dev->channels = adc084s021_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);

	/* Create SPI transfer for channel reads */
	adc->spi_trans.tx_buf = adc->tx_buf;
	adc->spi_trans.rx_buf = adc->rx_buf;
	adc->spi_trans.len = 4; /* Trash + single channel */
	spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);

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

	mutex_init(&adc->lock);

	/* Setup triggered buffer with pollfunction */
	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
	adc084s021_buffer_trigger_handler,
	&adc084s021_buffer_setup_ops);
	if (ret) {
	dev_err(&spi->dev, "Failed to setup triggered buffer\n");
	return ret;
	}

	return devm_iio_device_register(&spi->dev, indio_dev);
	}

	static const struct of_device_id adc084s021_of_match[] = {
	{ .compatible = "ti,adc084s021", },
	{},
	};
	MODULE_DEVICE_TABLE(of, adc084s021_of_match);

	static const struct spi_device_id adc084s021_id[] = {
	{ ADC084S021_DRIVER_NAME, 0},
	{}
	};
	MODULE_DEVICE_TABLE(spi, adc084s021_id);

	static struct spi_driver adc084s021_driver = {
	.driver = {
	.name = ADC084S021_DRIVER_NAME,
	.of_match_table = of_match_ptr(adc084s021_of_match),
	},
	.probe = adc084s021_probe,
	.id_table = adc084s021_id,
	};
	module_spi_driver(adc084s021_driver);

	MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
	MODULE_DESCRIPTION("Texas Instruments ADC084S021");
	MODULE_LICENSE("GPL v2");
	MODULE_VERSION("1.0");