drivers/iio/adc/ti-adc0832.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver
  *
  * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
  *
  * Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf
  */

 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
 #include <linux/spi/spi.h>
 #include <linux/iio/iio.h>
 #include <linux/regulator/consumer.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/trigger.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/trigger_consumer.h>

 enum {
 	adc0831,
 	adc0832,
 	adc0834,
 	adc0838,
 };

 struct adc0832 {
 	struct spi_device *spi;
 	struct regulator *reg;
 	struct mutex lock;
 	u8 mux_bits;

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

 #define ADC0832_VOLTAGE_CHANNEL(chan)					\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
 		.channel = chan,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
 		.scan_index = chan,					\
 		.scan_type = {						\
 			.sign = 'u',					\
 			.realbits = 8,					\
 			.storagebits = 8,				\
 		},							\
 	}

 #define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)			\
 	{								\
 		.type = IIO_VOLTAGE,					\
 		.indexed = 1,						\
 		.channel = (chan1),					\
 		.channel2 = (chan2),					\
 		.differential = 1,					\
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
 		.scan_index = si,					\
 		.scan_type = {						\
 			.sign = 'u',					\
 			.realbits = 8,					\
 			.storagebits = 8,				\
 		},							\
 	}

 static const struct iio_chan_spec adc0831_channels[] = {
 	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0),
 	IIO_CHAN_SOFT_TIMESTAMP(1),
 };

 static const struct iio_chan_spec adc0832_channels[] = {
 	ADC0832_VOLTAGE_CHANNEL(0),
 	ADC0832_VOLTAGE_CHANNEL(1),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
 	IIO_CHAN_SOFT_TIMESTAMP(4),
 };

 static const struct iio_chan_spec adc0834_channels[] = {
 	ADC0832_VOLTAGE_CHANNEL(0),
 	ADC0832_VOLTAGE_CHANNEL(1),
 	ADC0832_VOLTAGE_CHANNEL(2),
 	ADC0832_VOLTAGE_CHANNEL(3),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7),
 	IIO_CHAN_SOFT_TIMESTAMP(8),
 };

 static const struct iio_chan_spec adc0838_channels[] = {
 	ADC0832_VOLTAGE_CHANNEL(0),
 	ADC0832_VOLTAGE_CHANNEL(1),
 	ADC0832_VOLTAGE_CHANNEL(2),
 	ADC0832_VOLTAGE_CHANNEL(3),
 	ADC0832_VOLTAGE_CHANNEL(4),
 	ADC0832_VOLTAGE_CHANNEL(5),
 	ADC0832_VOLTAGE_CHANNEL(6),
 	ADC0832_VOLTAGE_CHANNEL(7),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 	ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 	IIO_CHAN_SOFT_TIMESTAMP(16),
 };

 static int adc0831_adc_conversion(struct adc0832 *adc)
 {
 	struct spi_device *spi = adc->spi;
 	int ret;

 	ret = spi_read(spi, &adc->rx_buf, 2);
 	if (ret)
 		return ret;

 	/*
 	 * Skip TRI-STATE and a leading zero
 	 */
 	return (adc->rx_buf[0] << 2 & 0xff) | (adc->rx_buf[1] >> 6);
 }

 static int adc0832_adc_conversion(struct adc0832 *adc, int channel,
 				bool differential)
 {
 	struct spi_device *spi = adc->spi;
 	struct spi_transfer xfer = {
 		.tx_buf = adc->tx_buf,
 		.rx_buf = adc->rx_buf,
 		.len = 2,
 	};
 	int ret;

 	if (!adc->mux_bits)
 		return adc0831_adc_conversion(adc);

 	/* start bit */
 	adc->tx_buf[0] = 1 << (adc->mux_bits + 1);
 	/* single-ended or differential */
 	adc->tx_buf[0] |= differential ? 0 : (1 << adc->mux_bits);
 	/* odd / sign */
 	adc->tx_buf[0] |= (channel % 2) << (adc->mux_bits - 1);
 	/* select */
 	if (adc->mux_bits > 1)
 		adc->tx_buf[0] |= channel / 2;

 	/* align Data output BIT7 (MSB) to 8-bit boundary */
 	adc->tx_buf[0] <<= 1;

 	ret = spi_sync_transfer(spi, &xfer, 1);
 	if (ret)
 		return ret;

 	return adc->rx_buf[1];
 }

 static int adc0832_read_raw(struct iio_dev *iio,
 			struct iio_chan_spec const *channel, int *value,
 			int *shift, long mask)
 {
 	struct adc0832 *adc = iio_priv(iio);

 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&adc->lock);
 		*value = adc0832_adc_conversion(adc, channel->channel,
 						channel->differential);
 		mutex_unlock(&adc->lock);
 		if (*value < 0)
 			return *value;

 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		*value = regulator_get_voltage(adc->reg);
 		if (*value < 0)
 			return *value;

 		/* convert regulator output voltage to mV */
 		*value /= 1000;
 		*shift = 8;

 		return IIO_VAL_FRACTIONAL_LOG2;
 	}

 	return -EINVAL;
 }

 static const struct iio_info adc0832_info = {
 	.read_raw = adc0832_read_raw,
 };

 static irqreturn_t adc0832_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adc0832 *adc = iio_priv(indio_dev);
 	u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */
 	int scan_index;
 	int i = 0;

 	mutex_lock(&adc->lock);

 	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
 			 indio_dev->masklength) {
 		const struct iio_chan_spec *scan_chan =
 				&indio_dev->channels[scan_index];
 		int ret = adc0832_adc_conversion(adc, scan_chan->channel,
 						 scan_chan->differential);
 		if (ret < 0) {
 			dev_warn(&adc->spi->dev,
 				 "failed to get conversion data\n");
 			goto out;
 		}

 		data[i] = ret;
 		i++;
 	}
 	iio_push_to_buffers_with_timestamp(indio_dev, data,
 					   iio_get_time_ns(indio_dev));
 out:
 	mutex_unlock(&adc->lock);

 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static int adc0832_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
 	struct adc0832 *adc;
 	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;
 	mutex_init(&adc->lock);

 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->info = &adc0832_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	switch (spi_get_device_id(spi)->driver_data) {
 	case adc0831:
 		adc->mux_bits = 0;
 		indio_dev->channels = adc0831_channels;
 		indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);
 		break;
 	case adc0832:
 		adc->mux_bits = 1;
 		indio_dev->channels = adc0832_channels;
 		indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);
 		break;
 	case adc0834:
 		adc->mux_bits = 2;
 		indio_dev->channels = adc0834_channels;
 		indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);
 		break;
 	case adc0838:
 		adc->mux_bits = 3;
 		indio_dev->channels = adc0838_channels;
 		indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);
 		break;
 	default:
 		return -EINVAL;
 	}

 	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)
 		return ret;

 	spi_set_drvdata(spi, indio_dev);

 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 					 adc0832_trigger_handler, NULL);
 	if (ret)
 		goto err_reg_disable;

 	ret = iio_device_register(indio_dev);
 	if (ret)
 		goto err_buffer_cleanup;

 	return 0;
 err_buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 err_reg_disable:
 	regulator_disable(adc->reg);

 	return ret;
 }

 static int adc0832_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct adc0832 *adc = iio_priv(indio_dev);

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

 	return 0;
 }

 static const struct of_device_id adc0832_dt_ids[] = {
 	{ .compatible = "ti,adc0831", },
 	{ .compatible = "ti,adc0832", },
 	{ .compatible = "ti,adc0834", },
 	{ .compatible = "ti,adc0838", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, adc0832_dt_ids);

 static const struct spi_device_id adc0832_id[] = {
 	{ "adc0831", adc0831 },
 	{ "adc0832", adc0832 },
 	{ "adc0834", adc0834 },
 	{ "adc0838", adc0838 },
 	{}
 };
 MODULE_DEVICE_TABLE(spi, adc0832_id);

 static struct spi_driver adc0832_driver = {
 	.driver = {
 		.name = "adc0832",
 		.of_match_table = adc0832_dt_ids,
 	},
 	.probe = adc0832_probe,
 	.remove = adc0832_remove,
 	.id_table = adc0832_id,
 };
 module_spi_driver(adc0832_driver);

 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* ADC0831/ADC0832/ADC0834/ADC0838 8-bit ADC driver
	*
	* Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
	*
	* Datasheet: https://www.ti.com/lit/ds/symlink/adc0832-n.pdf
	*/

	#include <linux/module.h>
	#include <linux/mod_devicetable.h>
	#include <linux/spi/spi.h>
	#include <linux/iio/iio.h>
	#include <linux/regulator/consumer.h>
	#include <linux/iio/buffer.h>
	#include <linux/iio/trigger.h>
	#include <linux/iio/triggered_buffer.h>
	#include <linux/iio/trigger_consumer.h>

	enum {
	adc0831,
	adc0832,
	adc0834,
	adc0838,
	};

	struct adc0832 {
	struct spi_device *spi;
	struct regulator *reg;
	struct mutex lock;
	u8 mux_bits;

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

	#define ADC0832_VOLTAGE_CHANNEL(chan) \
	{ \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = chan, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.scan_index = chan, \
	.scan_type = { \
	.sign = 'u', \
	.realbits = 8, \
	.storagebits = 8, \
	}, \
	}

	#define ADC0832_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \
	{ \
	.type = IIO_VOLTAGE, \
	.indexed = 1, \
	.channel = (chan1), \
	.channel2 = (chan2), \
	.differential = 1, \
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
	.scan_index = si, \
	.scan_type = { \
	.sign = 'u', \
	.realbits = 8, \
	.storagebits = 8, \
	}, \
	}

	static const struct iio_chan_spec adc0831_channels[] = {
	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 0),
	IIO_CHAN_SOFT_TIMESTAMP(1),
	};

	static const struct iio_chan_spec adc0832_channels[] = {
	ADC0832_VOLTAGE_CHANNEL(0),
	ADC0832_VOLTAGE_CHANNEL(1),
	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
	IIO_CHAN_SOFT_TIMESTAMP(4),
	};

	static const struct iio_chan_spec adc0834_channels[] = {
	ADC0832_VOLTAGE_CHANNEL(0),
	ADC0832_VOLTAGE_CHANNEL(1),
	ADC0832_VOLTAGE_CHANNEL(2),
	ADC0832_VOLTAGE_CHANNEL(3),
	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 4),
	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 5),
	ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 6),
	ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 7),
	IIO_CHAN_SOFT_TIMESTAMP(8),
	};

	static const struct iio_chan_spec adc0838_channels[] = {
	ADC0832_VOLTAGE_CHANNEL(0),
	ADC0832_VOLTAGE_CHANNEL(1),
	ADC0832_VOLTAGE_CHANNEL(2),
	ADC0832_VOLTAGE_CHANNEL(3),
	ADC0832_VOLTAGE_CHANNEL(4),
	ADC0832_VOLTAGE_CHANNEL(5),
	ADC0832_VOLTAGE_CHANNEL(6),
	ADC0832_VOLTAGE_CHANNEL(7),
	ADC0832_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
	ADC0832_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
	ADC0832_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
	ADC0832_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
	ADC0832_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
	ADC0832_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
	ADC0832_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
	ADC0832_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
	IIO_CHAN_SOFT_TIMESTAMP(16),
	};

	static int adc0831_adc_conversion(struct adc0832 *adc)
	{
	struct spi_device *spi = adc->spi;
	int ret;

	ret = spi_read(spi, &adc->rx_buf, 2);
	if (ret)
	return ret;

	/*
	* Skip TRI-STATE and a leading zero
	*/
	return (adc->rx_buf[0] << 2 & 0xff) \| (adc->rx_buf[1] >> 6);
	}

	static int adc0832_adc_conversion(struct adc0832 *adc, int channel,
	bool differential)
	{
	struct spi_device *spi = adc->spi;
	struct spi_transfer xfer = {
	.tx_buf = adc->tx_buf,
	.rx_buf = adc->rx_buf,
	.len = 2,
	};
	int ret;

	if (!adc->mux_bits)
	return adc0831_adc_conversion(adc);

	/* start bit */
	adc->tx_buf[0] = 1 << (adc->mux_bits + 1);
	/* single-ended or differential */
	adc->tx_buf[0] \|= differential ? 0 : (1 << adc->mux_bits);
	/* odd / sign */
	adc->tx_buf[0] \|= (channel % 2) << (adc->mux_bits - 1);
	/* select */
	if (adc->mux_bits > 1)
	adc->tx_buf[0] \|= channel / 2;

	/* align Data output BIT7 (MSB) to 8-bit boundary */
	adc->tx_buf[0] <<= 1;

	ret = spi_sync_transfer(spi, &xfer, 1);
	if (ret)
	return ret;

	return adc->rx_buf[1];
	}

	static int adc0832_read_raw(struct iio_dev *iio,
	struct iio_chan_spec const channel, int value,
	int *shift, long mask)
	{
	struct adc0832 *adc = iio_priv(iio);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
	mutex_lock(&adc->lock);
	*value = adc0832_adc_conversion(adc, channel->channel,
	channel->differential);
	mutex_unlock(&adc->lock);
	if (*value < 0)
	return *value;

	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	*value = regulator_get_voltage(adc->reg);
	if (*value < 0)
	return *value;

	/* convert regulator output voltage to mV */
	*value /= 1000;
	*shift = 8;

	return IIO_VAL_FRACTIONAL_LOG2;
	}

	return -EINVAL;
	}

	static const struct iio_info adc0832_info = {
	.read_raw = adc0832_read_raw,
	};

	static irqreturn_t adc0832_trigger_handler(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct adc0832 *adc = iio_priv(indio_dev);
	u8 data[24] = { }; /* 16x 1 byte ADC data + 8 bytes timestamp */
	int scan_index;
	int i = 0;

	mutex_lock(&adc->lock);

	for_each_set_bit(scan_index, indio_dev->active_scan_mask,
	indio_dev->masklength) {
	const struct iio_chan_spec *scan_chan =
	&indio_dev->channels[scan_index];
	int ret = adc0832_adc_conversion(adc, scan_chan->channel,
	scan_chan->differential);
	if (ret < 0) {
	dev_warn(&adc->spi->dev,
	"failed to get conversion data\n");
	goto out;
	}

	data[i] = ret;
	i++;
	}
	iio_push_to_buffers_with_timestamp(indio_dev, data,
	iio_get_time_ns(indio_dev));
	out:
	mutex_unlock(&adc->lock);

	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static int adc0832_probe(struct spi_device *spi)
	{
	struct iio_dev *indio_dev;
	struct adc0832 *adc;
	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;
	mutex_init(&adc->lock);

	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->info = &adc0832_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	switch (spi_get_device_id(spi)->driver_data) {
	case adc0831:
	adc->mux_bits = 0;
	indio_dev->channels = adc0831_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc0831_channels);
	break;
	case adc0832:
	adc->mux_bits = 1;
	indio_dev->channels = adc0832_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc0832_channels);
	break;
	case adc0834:
	adc->mux_bits = 2;
	indio_dev->channels = adc0834_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc0834_channels);
	break;
	case adc0838:
	adc->mux_bits = 3;
	indio_dev->channels = adc0838_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc0838_channels);
	break;
	default:
	return -EINVAL;
	}

	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)
	return ret;

	spi_set_drvdata(spi, indio_dev);

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
	adc0832_trigger_handler, NULL);
	if (ret)
	goto err_reg_disable;

	ret = iio_device_register(indio_dev);
	if (ret)
	goto err_buffer_cleanup;

	return 0;
	err_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
	err_reg_disable:
	regulator_disable(adc->reg);

	return ret;
	}

	static int adc0832_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct adc0832 *adc = iio_priv(indio_dev);

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

	return 0;
	}

	static const struct of_device_id adc0832_dt_ids[] = {
	{ .compatible = "ti,adc0831", },
	{ .compatible = "ti,adc0832", },
	{ .compatible = "ti,adc0834", },
	{ .compatible = "ti,adc0838", },
	{}
	};
	MODULE_DEVICE_TABLE(of, adc0832_dt_ids);

	static const struct spi_device_id adc0832_id[] = {
	{ "adc0831", adc0831 },
	{ "adc0832", adc0832 },
	{ "adc0834", adc0834 },
	{ "adc0838", adc0838 },
	{}
	};
	MODULE_DEVICE_TABLE(spi, adc0832_id);

	static struct spi_driver adc0832_driver = {
	.driver = {
	.name = "adc0832",
	.of_match_table = adc0832_dt_ids,
	},
	.probe = adc0832_probe,
	.remove = adc0832_remove,
	.id_table = adc0832_id,
	};
	module_spi_driver(adc0832_driver);

	MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
	MODULE_DESCRIPTION("ADC0831/ADC0832/ADC0834/ADC0838 driver");
	MODULE_LICENSE("GPL v2");