drivers/iio/adc/ad7887.c - third_party/linux - Git at Google

 /*
  * AD7887 SPI ADC driver
  *
  * Copyright 2010-2011 Analog Devices Inc.
  *
  * Licensed under the GPL-2.
  */

 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/spi/spi.h>
 #include <linux/regulator/consumer.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/bitops.h>

 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/buffer.h>

 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>

 #include <linux/platform_data/ad7887.h>

 #define AD7887_REF_DIS		BIT(5)	/* on-chip reference disable */
 #define AD7887_DUAL		BIT(4)	/* dual-channel mode */
 #define AD7887_CH_AIN1		BIT(3)	/* convert on channel 1, DUAL=1 */
 #define AD7887_CH_AIN0		0	/* convert on channel 0, DUAL=0,1 */
 #define AD7887_PM_MODE1		0	/* CS based shutdown */
 #define AD7887_PM_MODE2		1	/* full on */
 #define AD7887_PM_MODE3		2	/* auto shutdown after conversion */
 #define AD7887_PM_MODE4		3	/* standby mode */

 enum ad7887_channels {
 	AD7887_CH0,
 	AD7887_CH0_CH1,
 	AD7887_CH1,
 };

 /**
  * struct ad7887_chip_info - chip specifc information
  * @int_vref_mv:	the internal reference voltage
  * @channel:		channel specification
  */
 struct ad7887_chip_info {
 	u16				int_vref_mv;
 	struct iio_chan_spec		channel[3];
 };

 struct ad7887_state {
 	struct spi_device		*spi;
 	const struct ad7887_chip_info	*chip_info;
 	struct regulator		*reg;
 	struct spi_transfer		xfer[4];
 	struct spi_message		msg[3];
 	struct spi_message		*ring_msg;
 	unsigned char			tx_cmd_buf[4];

 	/*
 	 * DMA (thus cache coherency maintenance) requires the
 	 * transfer buffers to live in their own cache lines.
 	 * Buffer needs to be large enough to hold two 16 bit samples and a
 	 * 64 bit aligned 64 bit timestamp.
 	 */
 	unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
 		____cacheline_aligned;
 };

 enum ad7887_supported_device_ids {
 	ID_AD7887
 };

 static int ad7887_ring_preenable(struct iio_dev *indio_dev)
 {
 	struct ad7887_state *st = iio_priv(indio_dev);

 	/* We know this is a single long so can 'cheat' */
 	switch (*indio_dev->active_scan_mask) {
 	case (1 << 0):
 		st->ring_msg = &st->msg[AD7887_CH0];
 		break;
 	case (1 << 1):
 		st->ring_msg = &st->msg[AD7887_CH1];
 		/* Dummy read: push CH1 setting down to hardware */
 		spi_sync(st->spi, st->ring_msg);
 		break;
 	case ((1 << 1) | (1 << 0)):
 		st->ring_msg = &st->msg[AD7887_CH0_CH1];
 		break;
 	}

 	return 0;
 }

 static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
 {
 	struct ad7887_state *st = iio_priv(indio_dev);

 	/* dummy read: restore default CH0 settin */
 	return spi_sync(st->spi, &st->msg[AD7887_CH0]);
 }

 /**
  * ad7887_trigger_handler() bh of trigger launched polling to ring buffer
  *
  * Currently there is no option in this driver to disable the saving of
  * timestamps within the ring.
  **/
 static irqreturn_t ad7887_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ad7887_state *st = iio_priv(indio_dev);
 	int b_sent;

 	b_sent = spi_sync(st->spi, st->ring_msg);
 	if (b_sent)
 		goto done;

 	iio_push_to_buffers_with_timestamp(indio_dev, st->data,
 		iio_get_time_ns(indio_dev));
 done:
 	iio_trigger_notify_done(indio_dev->trig);

 	return IRQ_HANDLED;
 }

 static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
 	.preenable = &ad7887_ring_preenable,
 	.postenable = &iio_triggered_buffer_postenable,
 	.predisable = &iio_triggered_buffer_predisable,
 	.postdisable = &ad7887_ring_postdisable,
 };

 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
 {
 	int ret = spi_sync(st->spi, &st->msg[ch]);
 	if (ret)
 		return ret;

 	return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
 }

 static int ad7887_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val,
 			   int *val2,
 			   long m)
 {
 	int ret;
 	struct ad7887_state *st = iio_priv(indio_dev);

 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
 		ret = iio_device_claim_direct_mode(indio_dev);
 		if (ret)
 			return ret;
 		ret = ad7887_scan_direct(st, chan->address);
 		iio_device_release_direct_mode(indio_dev);

 		if (ret < 0)
 			return ret;
 		*val = ret >> chan->scan_type.shift;
 		*val &= GENMASK(chan->scan_type.realbits - 1, 0);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		if (st->reg) {
 			*val = regulator_get_voltage(st->reg);
 			if (*val < 0)
 				return *val;
 			*val /= 1000;
 		} else {
 			*val = st->chip_info->int_vref_mv;
 		}

 		*val2 = chan->scan_type.realbits;

 		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 	return -EINVAL;
 }


 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
 	/*
 	 * More devices added in future
 	 */
 	[ID_AD7887] = {
 		.channel[0] = {
 			.type = IIO_VOLTAGE,
 			.indexed = 1,
 			.channel = 1,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 			.address = 1,
 			.scan_index = 1,
 			.scan_type = {
 				.sign = 'u',
 				.realbits = 12,
 				.storagebits = 16,
 				.shift = 0,
 				.endianness = IIO_BE,
 			},
 		},
 		.channel[1] = {
 			.type = IIO_VOLTAGE,
 			.indexed = 1,
 			.channel = 0,
 			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 			.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 			.address = 0,
 			.scan_index = 0,
 			.scan_type = {
 				.sign = 'u',
 				.realbits = 12,
 				.storagebits = 16,
 				.shift = 0,
 				.endianness = IIO_BE,
 			},
 		},
 		.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
 		.int_vref_mv = 2500,
 	},
 };

 static const struct iio_info ad7887_info = {
 	.read_raw = &ad7887_read_raw,
 };

 static int ad7887_probe(struct spi_device *spi)
 {
 	struct ad7887_platform_data *pdata = spi->dev.platform_data;
 	struct ad7887_state *st;
 	struct iio_dev *indio_dev;
 	uint8_t mode;
 	int ret;

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

 	st = iio_priv(indio_dev);

 	if (!pdata || !pdata->use_onchip_ref) {
 		st->reg = devm_regulator_get(&spi->dev, "vref");
 		if (IS_ERR(st->reg))
 			return PTR_ERR(st->reg);

 		ret = regulator_enable(st->reg);
 		if (ret)
 			return ret;
 	}

 	st->chip_info =
 		&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];

 	spi_set_drvdata(spi, indio_dev);
 	st->spi = spi;

 	/* Estabilish that the iio_dev is a child of the spi 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->info = &ad7887_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	/* Setup default message */

 	mode = AD7887_PM_MODE4;
 	if (!pdata || !pdata->use_onchip_ref)
 		mode |= AD7887_REF_DIS;
 	if (pdata && pdata->en_dual)
 		mode |= AD7887_DUAL;

 	st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;

 	st->xfer[0].rx_buf = &st->data[0];
 	st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
 	st->xfer[0].len = 2;

 	spi_message_init(&st->msg[AD7887_CH0]);
 	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);

 	if (pdata && pdata->en_dual) {
 		st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;

 		st->xfer[1].rx_buf = &st->data[0];
 		st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
 		st->xfer[1].len = 2;

 		st->xfer[2].rx_buf = &st->data[2];
 		st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
 		st->xfer[2].len = 2;

 		spi_message_init(&st->msg[AD7887_CH0_CH1]);
 		spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
 		spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);

 		st->xfer[3].rx_buf = &st->data[2];
 		st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
 		st->xfer[3].len = 2;

 		spi_message_init(&st->msg[AD7887_CH1]);
 		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);

 		indio_dev->channels = st->chip_info->channel;
 		indio_dev->num_channels = 3;
 	} else {
 		indio_dev->channels = &st->chip_info->channel[1];
 		indio_dev->num_channels = 2;
 	}

 	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
 			&ad7887_trigger_handler, &ad7887_ring_setup_ops);
 	if (ret)
 		goto error_disable_reg;

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

 	return 0;
 error_unregister_ring:
 	iio_triggered_buffer_cleanup(indio_dev);
 error_disable_reg:
 	if (st->reg)
 		regulator_disable(st->reg);

 	return ret;
 }

 static int ad7887_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);
 	struct ad7887_state *st = iio_priv(indio_dev);

 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	if (st->reg)
 		regulator_disable(st->reg);

 	return 0;
 }

 static const struct spi_device_id ad7887_id[] = {
 	{"ad7887", ID_AD7887},
 	{}
 };
 MODULE_DEVICE_TABLE(spi, ad7887_id);

 static struct spi_driver ad7887_driver = {
 	.driver = {
 		.name	= "ad7887",
 	},
 	.probe		= ad7887_probe,
 	.remove		= ad7887_remove,
 	.id_table	= ad7887_id,
 };
 module_spi_driver(ad7887_driver);

 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
 MODULE_LICENSE("GPL v2");
	/*
	* AD7887 SPI ADC driver
	*
	* Copyright 2010-2011 Analog Devices Inc.
	*
	* Licensed under the GPL-2.
	*/

	#include <linux/device.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/sysfs.h>
	#include <linux/spi/spi.h>
	#include <linux/regulator/consumer.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/bitops.h>

	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/iio/buffer.h>

	#include <linux/iio/trigger_consumer.h>
	#include <linux/iio/triggered_buffer.h>

	#include <linux/platform_data/ad7887.h>

	#define AD7887_REF_DIS BIT(5) /* on-chip reference disable */
	#define AD7887_DUAL BIT(4) /* dual-channel mode */
	#define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */
	#define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */
	#define AD7887_PM_MODE1 0 /* CS based shutdown */
	#define AD7887_PM_MODE2 1 /* full on */
	#define AD7887_PM_MODE3 2 /* auto shutdown after conversion */
	#define AD7887_PM_MODE4 3 /* standby mode */

	enum ad7887_channels {
	AD7887_CH0,
	AD7887_CH0_CH1,
	AD7887_CH1,
	};

	/**
	* struct ad7887_chip_info - chip specifc information
	* @int_vref_mv: the internal reference voltage
	* @channel: channel specification
	*/
	struct ad7887_chip_info {
	u16 int_vref_mv;
	struct iio_chan_spec channel[3];
	};

	struct ad7887_state {
	struct spi_device *spi;
	const struct ad7887_chip_info *chip_info;
	struct regulator *reg;
	struct spi_transfer xfer[4];
	struct spi_message msg[3];
	struct spi_message *ring_msg;
	unsigned char tx_cmd_buf[4];

	/*
	* DMA (thus cache coherency maintenance) requires the
	* transfer buffers to live in their own cache lines.
	* Buffer needs to be large enough to hold two 16 bit samples and a
	* 64 bit aligned 64 bit timestamp.
	*/
	unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
	____cacheline_aligned;
	};

	enum ad7887_supported_device_ids {
	ID_AD7887
	};

	static int ad7887_ring_preenable(struct iio_dev *indio_dev)
	{
	struct ad7887_state *st = iio_priv(indio_dev);

	/* We know this is a single long so can 'cheat' */
	switch (*indio_dev->active_scan_mask) {
	case (1 << 0):
	st->ring_msg = &st->msg[AD7887_CH0];
	break;
	case (1 << 1):
	st->ring_msg = &st->msg[AD7887_CH1];
	/* Dummy read: push CH1 setting down to hardware */
	spi_sync(st->spi, st->ring_msg);
	break;
	case ((1 << 1) \| (1 << 0)):
	st->ring_msg = &st->msg[AD7887_CH0_CH1];
	break;
	}

	return 0;
	}

	static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
	{
	struct ad7887_state *st = iio_priv(indio_dev);

	/* dummy read: restore default CH0 settin */
	return spi_sync(st->spi, &st->msg[AD7887_CH0]);
	}

	/**
	* ad7887_trigger_handler() bh of trigger launched polling to ring buffer
	*
	* Currently there is no option in this driver to disable the saving of
	* timestamps within the ring.
	**/
	static irqreturn_t ad7887_trigger_handler(int irq, void *p)
	{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7887_state *st = iio_priv(indio_dev);
	int b_sent;

	b_sent = spi_sync(st->spi, st->ring_msg);
	if (b_sent)
	goto done;

	iio_push_to_buffers_with_timestamp(indio_dev, st->data,
	iio_get_time_ns(indio_dev));
	done:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
	}

	static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
	.preenable = &ad7887_ring_preenable,
	.postenable = &iio_triggered_buffer_postenable,
	.predisable = &iio_triggered_buffer_predisable,
	.postdisable = &ad7887_ring_postdisable,
	};

	static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
	{
	int ret = spi_sync(st->spi, &st->msg[ch]);
	if (ret)
	return ret;

	return (st->data[(ch * 2)] << 8) \| st->data[(ch * 2) + 1];
	}

	static int ad7887_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan,
	int *val,
	int *val2,
	long m)
	{
	int ret;
	struct ad7887_state *st = iio_priv(indio_dev);

	switch (m) {
	case IIO_CHAN_INFO_RAW:
	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
	return ret;
	ret = ad7887_scan_direct(st, chan->address);
	iio_device_release_direct_mode(indio_dev);

	if (ret < 0)
	return ret;
	*val = ret >> chan->scan_type.shift;
	*val &= GENMASK(chan->scan_type.realbits - 1, 0);
	return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
	if (st->reg) {
	*val = regulator_get_voltage(st->reg);
	if (*val < 0)
	return *val;
	*val /= 1000;
	} else {
	*val = st->chip_info->int_vref_mv;
	}

	*val2 = chan->scan_type.realbits;

	return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
	}


	static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
	/*
	* More devices added in future
	*/
	[ID_AD7887] = {
	.channel[0] = {
	.type = IIO_VOLTAGE,
	.indexed = 1,
	.channel = 1,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
	.address = 1,
	.scan_index = 1,
	.scan_type = {
	.sign = 'u',
	.realbits = 12,
	.storagebits = 16,
	.shift = 0,
	.endianness = IIO_BE,
	},
	},
	.channel[1] = {
	.type = IIO_VOLTAGE,
	.indexed = 1,
	.channel = 0,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
	.address = 0,
	.scan_index = 0,
	.scan_type = {
	.sign = 'u',
	.realbits = 12,
	.storagebits = 16,
	.shift = 0,
	.endianness = IIO_BE,
	},
	},
	.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
	.int_vref_mv = 2500,
	},
	};

	static const struct iio_info ad7887_info = {
	.read_raw = &ad7887_read_raw,
	};

	static int ad7887_probe(struct spi_device *spi)
	{
	struct ad7887_platform_data *pdata = spi->dev.platform_data;
	struct ad7887_state *st;
	struct iio_dev *indio_dev;
	uint8_t mode;
	int ret;

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

	st = iio_priv(indio_dev);

	if (!pdata \|\| !pdata->use_onchip_ref) {
	st->reg = devm_regulator_get(&spi->dev, "vref");
	if (IS_ERR(st->reg))
	return PTR_ERR(st->reg);

	ret = regulator_enable(st->reg);
	if (ret)
	return ret;
	}

	st->chip_info =
	&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];

	spi_set_drvdata(spi, indio_dev);
	st->spi = spi;

	/* Estabilish that the iio_dev is a child of the spi 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->info = &ad7887_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* Setup default message */

	mode = AD7887_PM_MODE4;
	if (!pdata \|\| !pdata->use_onchip_ref)
	mode \|= AD7887_REF_DIS;
	if (pdata && pdata->en_dual)
	mode \|= AD7887_DUAL;

	st->tx_cmd_buf[0] = AD7887_CH_AIN0 \| mode;

	st->xfer[0].rx_buf = &st->data[0];
	st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
	st->xfer[0].len = 2;

	spi_message_init(&st->msg[AD7887_CH0]);
	spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);

	if (pdata && pdata->en_dual) {
	st->tx_cmd_buf[2] = AD7887_CH_AIN1 \| mode;

	st->xfer[1].rx_buf = &st->data[0];
	st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
	st->xfer[1].len = 2;

	st->xfer[2].rx_buf = &st->data[2];
	st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
	st->xfer[2].len = 2;

	spi_message_init(&st->msg[AD7887_CH0_CH1]);
	spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
	spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);

	st->xfer[3].rx_buf = &st->data[2];
	st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
	st->xfer[3].len = 2;

	spi_message_init(&st->msg[AD7887_CH1]);
	spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);

	indio_dev->channels = st->chip_info->channel;
	indio_dev->num_channels = 3;
	} else {
	indio_dev->channels = &st->chip_info->channel[1];
	indio_dev->num_channels = 2;
	}

	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
	&ad7887_trigger_handler, &ad7887_ring_setup_ops);
	if (ret)
	goto error_disable_reg;

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

	return 0;
	error_unregister_ring:
	iio_triggered_buffer_cleanup(indio_dev);
	error_disable_reg:
	if (st->reg)
	regulator_disable(st->reg);

	return ret;
	}

	static int ad7887_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7887_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	if (st->reg)
	regulator_disable(st->reg);

	return 0;
	}

	static const struct spi_device_id ad7887_id[] = {
	{"ad7887", ID_AD7887},
	{}
	};
	MODULE_DEVICE_TABLE(spi, ad7887_id);

	static struct spi_driver ad7887_driver = {
	.driver = {
	.name = "ad7887",
	},
	.probe = ad7887_probe,
	.remove = ad7887_remove,
	.id_table = ad7887_id,
	};
	module_spi_driver(ad7887_driver);

	MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
	MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
	MODULE_LICENSE("GPL v2");