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Commit aa16c6bd authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
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iio:adc: Add support for AD7766/AD7767 

Add support for the AD7766, AD7766-1, AD7766-2, AD7767, AD7767-1, AD7767-2
Analog to Digital converters. It's a family of single channel 24-bit SAR
ADCs. They are all digital interface compatible and the main difference is
the internal decimation rate and analog performance. For communication with
the host processor a SPI interface is used.

In addition the part has a data ready pin that is pulsed for one MCLK cycle
when a conversion has completed and can be used as a IIO trigger.

Datasheets:
	http://www.analog.com/media/en/technical-documentation/data-sheets/AD7766.pdf
	http://www.analog.com/media/en/technical-documentation/data-sheets/AD7767.pdf



Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent bea15d51

drivers/iio/adc/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -58,6 +58,18 @@ config AD7476 
	  To compile this driver as a module, choose M here: the

	  module will be called ad7476.



config AD7766

	tristate "Analog Devices AD7766/AD7767 ADC driver"

	depends on SPI_MASTER

	select IIO_BUFFER

	select IIO_TRIGGERED_BUFFER

	help

	  Say yes here to build support for Analog Devices AD7766, AD7766-1,

	  AD7766-2, AD7767, AD7767-1, AD7767-2 SPI analog to digital converters.



	  To compile this driver as a module, choose M here: the module will be

	  called ad7766.



config AD7791

	tristate "Analog Devices AD7791 ADC driver"

	depends on SPI

drivers/iio/adc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ obj-$(CONFIG_AD7291) += ad7291.o 
obj-$(CONFIG_AD7298) += ad7298.o

obj-$(CONFIG_AD7923) += ad7923.o

obj-$(CONFIG_AD7476) += ad7476.o

obj-$(CONFIG_AD7766) += ad7766.o

obj-$(CONFIG_AD7791) += ad7791.o

obj-$(CONFIG_AD7793) += ad7793.o

obj-$(CONFIG_AD7887) += ad7887.o

drivers/iio/adc/ad7766.c

0 → 100644
+330 −0
Original line number Diff line number Diff line 
/*

 * AD7766/AD7767 SPI ADC driver

 *

 * Copyright 2016 Analog Devices Inc.

 *

 * Licensed under the GPL-2 or later.

 */



#include <linux/clk.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/gpio/consumer.h>

#include <linux/module.h>

#include <linux/regulator/consumer.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>



#include <linux/iio/iio.h>

#include <linux/iio/buffer.h>

#include <linux/iio/trigger.h>

#include <linux/iio/trigger_consumer.h>

#include <linux/iio/triggered_buffer.h>



struct ad7766_chip_info {

	unsigned int decimation_factor;

};



enum {

	AD7766_SUPPLY_AVDD = 0,

	AD7766_SUPPLY_DVDD = 1,

	AD7766_SUPPLY_VREF = 2,

	AD7766_NUM_SUPPLIES = 3

};



struct ad7766 {

	const struct ad7766_chip_info *chip_info;

	struct spi_device *spi;

	struct clk *mclk;

	struct gpio_desc *pd_gpio;

	struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];



	struct iio_trigger *trig;



	struct spi_transfer xfer;

	struct spi_message msg;



	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 * Make the buffer large enough for one 24 bit sample and one 64 bit

	 * aligned 64 bit timestamp.

	 */

	unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)]

			____cacheline_aligned;

};



/*

 * AD7766 and AD7767 variations are interface compatible, the main difference is

 * analog performance. Both parts will use the same ID.

 */

enum ad7766_device_ids {

	ID_AD7766,

	ID_AD7766_1,

	ID_AD7766_2,

};



static irqreturn_t ad7766_trigger_handler(int irq, void *p)

{

	struct iio_poll_func *pf = p;

	struct iio_dev *indio_dev = pf->indio_dev;

	struct ad7766 *ad7766 = iio_priv(indio_dev);

	int ret;



	ret = spi_sync(ad7766->spi, &ad7766->msg);

	if (ret < 0)

		goto done;



	iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,

		pf->timestamp);

done:

	iio_trigger_notify_done(indio_dev->trig);



	return IRQ_HANDLED;

}



static int ad7766_preenable(struct iio_dev *indio_dev)

{

	struct ad7766 *ad7766 = iio_priv(indio_dev);

	int ret;



	ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);

	if (ret < 0) {

		dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",

			ret);

		return ret;

	}



	ret = clk_prepare_enable(ad7766->mclk);

	if (ret < 0) {

		dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);

		regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);

		return ret;

	}



	if (ad7766->pd_gpio)

		gpiod_set_value(ad7766->pd_gpio, 0);



	return 0;

}



static int ad7766_postdisable(struct iio_dev *indio_dev)

{

	struct ad7766 *ad7766 = iio_priv(indio_dev);



	if (ad7766->pd_gpio)

		gpiod_set_value(ad7766->pd_gpio, 1);



	/*

	 * The PD pin is synchronous to the clock, so give it some time to

	 * notice the change before we disable the clock.

	 */

	msleep(20);



	clk_disable_unprepare(ad7766->mclk);

	regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);



	return 0;

}



static int ad7766_read_raw(struct iio_dev *indio_dev,

	const struct iio_chan_spec *chan, int *val, int *val2, long info)

{

	struct ad7766 *ad7766 = iio_priv(indio_dev);

	struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;

	int scale_uv;



	switch (info) {

	case IIO_CHAN_INFO_SCALE:

		scale_uv = regulator_get_voltage(vref);

		if (scale_uv < 0)

			return scale_uv;

		*val = scale_uv / 1000;

		*val2 = chan->scan_type.realbits;

		return IIO_VAL_FRACTIONAL_LOG2;

	case IIO_CHAN_INFO_SAMP_FREQ:

		*val = clk_get_rate(ad7766->mclk) /

			ad7766->chip_info->decimation_factor;

		return IIO_VAL_INT;

	}

	return -EINVAL;

}



static const struct iio_chan_spec ad7766_channels[] = {

	{

		.type = IIO_VOLTAGE,

		.indexed = 1,

		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),

		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),

		.scan_type = {

			.sign = 's',

			.realbits = 24,

			.storagebits = 32,

			.endianness = IIO_BE,

		},

	},

	IIO_CHAN_SOFT_TIMESTAMP(1),

};



static const struct ad7766_chip_info ad7766_chip_info[] = {

	[ID_AD7766] = {

		.decimation_factor = 8,

	},

	[ID_AD7766_1] = {

		.decimation_factor = 16,

	},

	[ID_AD7766_2] = {

		.decimation_factor = 32,

	},

};



static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {

	.preenable = &ad7766_preenable,

	.postenable = &iio_triggered_buffer_postenable,

	.predisable = &iio_triggered_buffer_predisable,

	.postdisable = &ad7766_postdisable,

};



static const struct iio_info ad7766_info = {

	.driver_module = THIS_MODULE,

	.read_raw = &ad7766_read_raw,

};



static irqreturn_t ad7766_irq(int irq, void *private)

{

	iio_trigger_poll(private);

	return IRQ_HANDLED;

}



static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)

{

	struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);



	if (enable)

		enable_irq(ad7766->spi->irq);

	else

		disable_irq(ad7766->spi->irq);



	return 0;

}



static const struct iio_trigger_ops ad7766_trigger_ops = {

	.owner = THIS_MODULE,

	.set_trigger_state = ad7766_set_trigger_state,

	.validate_device = iio_trigger_validate_own_device,

};



static int ad7766_probe(struct spi_device *spi)

{

	const struct spi_device_id *id = spi_get_device_id(spi);

	struct iio_dev *indio_dev;

	struct ad7766 *ad7766;

	int ret;



	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));

	if (!indio_dev)

		return -ENOMEM;



	ad7766 = iio_priv(indio_dev);

	ad7766->chip_info = &ad7766_chip_info[id->driver_data];



	ad7766->mclk = devm_clk_get(&spi->dev, "mclk");

	if (IS_ERR(ad7766->mclk))

		return PTR_ERR(ad7766->mclk);



	ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";

	ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";

	ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";



	ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),

		ad7766->reg);

	if (IS_ERR(ad7766->reg))

		return PTR_ERR(ad7766->reg);



	ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",

		GPIOD_OUT_HIGH);

	if (IS_ERR(ad7766->pd_gpio))

		return PTR_ERR(ad7766->pd_gpio);



	indio_dev->dev.parent = &spi->dev;

	indio_dev->name = spi_get_device_id(spi)->name;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = ad7766_channels;

	indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);

	indio_dev->info = &ad7766_info;



	if (spi->irq > 0) {

		ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",

			indio_dev->name, indio_dev->id);

		if (!ad7766->trig)

			return -ENOMEM;



		ad7766->trig->ops = &ad7766_trigger_ops;

		ad7766->trig->dev.parent = &spi->dev;

		iio_trigger_set_drvdata(ad7766->trig, ad7766);



		ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,

			IRQF_TRIGGER_FALLING, dev_name(&spi->dev),

			ad7766->trig);

		if (ret < 0)

			return ret;



		/*

		 * The device generates interrupts as long as it is powered up.

		 * Some platforms might not allow the option to power it down so

		 * disable the interrupt to avoid extra load on the system

		 */

		disable_irq(spi->irq);



		ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);

		if (ret)

			return ret;

	}



	spi_set_drvdata(spi, indio_dev);



	ad7766->spi = spi;



	/* First byte always 0 */

	ad7766->xfer.rx_buf = &ad7766->data[1];

	ad7766->xfer.len = 3;



	spi_message_init(&ad7766->msg);

	spi_message_add_tail(&ad7766->xfer, &ad7766->msg);



	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,

		&iio_pollfunc_store_time, &ad7766_trigger_handler,

		&ad7766_buffer_setup_ops);

	if (ret)

		return ret;



	ret = devm_iio_device_register(&spi->dev, indio_dev);

	if (ret)

		return ret;

	return 0;

}



static const struct spi_device_id ad7766_id[] = {

	{"ad7766", ID_AD7766},

	{"ad7766-1", ID_AD7766_1},

	{"ad7766-2", ID_AD7766_2},

	{"ad7767", ID_AD7766},

	{"ad7767-1", ID_AD7766_1},

	{"ad7767-2", ID_AD7766_2},

	{}

};

MODULE_DEVICE_TABLE(spi, ad7766_id);



static struct spi_driver ad7766_driver = {

	.driver = {

		.name	= "ad7766",

	},

	.probe		= ad7766_probe,

	.id_table	= ad7766_id,

};

module_spi_driver(ad7766_driver);



MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");

MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");

MODULE_LICENSE("GPL v2");