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Commit 8ec4cf53 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
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iio:adc: Add AD7265/AD7266 support 



This patch adds support for the Analog Devices AD7265 and AD7266
Analog-to-Digital converters.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent c1f1a9d4

drivers/iio/adc/Kconfig

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@@ -3,6 +3,16 @@ 
#

menu "Analog to digital converters"



config AD7266

	tristate "Analog Devices AD7265/AD7266 ADC driver"

	depends on SPI_MASTER

	select IIO_BUFFER

	select IIO_TRIGGER

	select IIO_TRIGGERED_BUFFER

	help

	  Say yes here to build support for Analog Devices AD7265 and AD7266

	  ADCs.



config AT91_ADC

	tristate "Atmel AT91 ADC"

	depends on ARCH_AT91

drivers/iio/adc/Makefile

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@@ -2,4 +2,5 @@ 
# Makefile for IIO ADC drivers

#



obj-$(CONFIG_AD7266) += ad7266.o

obj-$(CONFIG_AT91_ADC) += at91_adc.o

drivers/iio/adc/ad7266.c

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/*

 * AD7266/65 SPI ADC driver

 *

 * Copyright 2012 Analog Devices Inc.

 *

 * Licensed under the GPL-2.

 */



#include <linux/device.h>

#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>

#include <linux/regulator/consumer.h>

#include <linux/err.h>

#include <linux/gpio.h>

#include <linux/module.h>



#include <linux/interrupt.h>



#include <linux/iio/iio.h>

#include <linux/iio/buffer.h>

#include <linux/iio/trigger_consumer.h>

#include <linux/iio/triggered_buffer.h>



#include <linux/platform_data/ad7266.h>



struct ad7266_state {

	struct spi_device	*spi;

	struct regulator	*reg;

	unsigned long		vref_uv;



	struct spi_transfer	single_xfer[3];

	struct spi_message	single_msg;



	enum ad7266_range	range;

	enum ad7266_mode	mode;

	bool			fixed_addr;

	struct gpio		gpios[3];



	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 * The buffer needs to be large enough to hold two samples (4 bytes) and

	 * the naturally aligned timestamp (8 bytes).

	 */

	uint8_t data[ALIGN(4, sizeof(s64)) + sizeof(s64)] ____cacheline_aligned;

};



static int ad7266_wakeup(struct ad7266_state *st)

{

	/* Any read with >= 2 bytes will wake the device */

	return spi_read(st->spi, st->data, 2);

}



static int ad7266_powerdown(struct ad7266_state *st)

{

	/* Any read with < 2 bytes will powerdown the device */

	return spi_read(st->spi, st->data, 1);

}



static int ad7266_preenable(struct iio_dev *indio_dev)

{

	struct ad7266_state *st = iio_priv(indio_dev);

	int ret;



	ret = ad7266_wakeup(st);

	if (ret)

		return ret;



	ret = iio_sw_buffer_preenable(indio_dev);

	if (ret)

		ad7266_powerdown(st);



	return ret;

}



static int ad7266_postdisable(struct iio_dev *indio_dev)

{

	struct ad7266_state *st = iio_priv(indio_dev);

	return ad7266_powerdown(st);

}



static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {

	.preenable = &ad7266_preenable,

	.postenable = &iio_triggered_buffer_postenable,

	.predisable = &iio_triggered_buffer_predisable,

	.postdisable = &ad7266_postdisable,

};



static irqreturn_t ad7266_trigger_handler(int irq, void *p)

{

	struct iio_poll_func *pf = p;

	struct iio_dev *indio_dev = pf->indio_dev;

	struct iio_buffer *buffer = indio_dev->buffer;

	struct ad7266_state *st = iio_priv(indio_dev);

	int ret;



	ret = spi_read(st->spi, st->data, 4);

	if (ret == 0) {

		if (indio_dev->scan_timestamp)

			((s64 *)st->data)[1] = pf->timestamp;

		iio_push_to_buffer(buffer, (u8 *)st->data, pf->timestamp);

	}



	iio_trigger_notify_done(indio_dev->trig);



	return IRQ_HANDLED;

}



static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)

{

	unsigned int i;



	if (st->fixed_addr)

		return;



	switch (st->mode) {

	case AD7266_MODE_SINGLE_ENDED:

		nr >>= 1;

		break;

	case AD7266_MODE_PSEUDO_DIFF:

		nr |= 1;

		break;

	case AD7266_MODE_DIFF:

		nr &= ~1;

		break;

	}



	for (i = 0; i < 3; ++i)

		gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));

}



static int ad7266_update_scan_mode(struct iio_dev *indio_dev,

	const unsigned long *scan_mask)

{

	struct ad7266_state *st = iio_priv(indio_dev);

	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);



	ad7266_select_input(st, nr);



	return 0;

}



static int ad7266_read_single(struct ad7266_state *st, int *val,

	unsigned int address)

{

	int ret;



	ad7266_select_input(st, address);



	ret = spi_sync(st->spi, &st->single_msg);

	*val = be16_to_cpu(st->data[address % 2]);



	return ret;

}



static int ad7266_read_raw(struct iio_dev *indio_dev,

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

{

	struct ad7266_state *st = iio_priv(indio_dev);

	unsigned long scale_uv;

	int ret;



	switch (m) {

	case IIO_CHAN_INFO_RAW:

		if (iio_buffer_enabled(indio_dev))

			return -EBUSY;



		ret = ad7266_read_single(st, val, chan->address);

		if (ret)

			return ret;



		*val = (*val >> 2) & 0xfff;

		if (chan->scan_type.sign == 's')

			*val = sign_extend32(*val, 11);



		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		scale_uv = (st->vref_uv * 100);

		if (st->mode == AD7266_MODE_DIFF)

			scale_uv *= 2;

		if (st->range == AD7266_RANGE_2VREF)

			scale_uv *= 2;



		scale_uv >>= chan->scan_type.realbits;

		*val =  scale_uv / 100000;

		*val2 = (scale_uv % 100000) * 10;

		return IIO_VAL_INT_PLUS_MICRO;

	case IIO_CHAN_INFO_OFFSET:

		if (st->range == AD7266_RANGE_2VREF &&

			st->mode != AD7266_MODE_DIFF)

			*val = 2048;

		else

			*val = 0;

		return IIO_VAL_INT;

	}

	return -EINVAL;

}



#define AD7266_CHAN(_chan, _sign) {			\

	.type = IIO_VOLTAGE,				\

	.indexed = 1,					\

	.channel = (_chan),				\

	.address = (_chan),				\

	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT	\

		| IIO_CHAN_INFO_SCALE_SHARED_BIT	\

		| IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\

	.scan_index = (_chan),				\

	.scan_type = {					\

		.sign = (_sign),			\

		.realbits = 12,				\

		.storagebits = 16,			\

		.shift = 2,				\

		.endianness = IIO_BE,			\

	},						\

}



#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \

const struct iio_chan_spec ad7266_channels_##_name[] = { \

	AD7266_CHAN(0, (_sign)), \

	AD7266_CHAN(1, (_sign)), \

	AD7266_CHAN(2, (_sign)), \

	AD7266_CHAN(3, (_sign)), \

	AD7266_CHAN(4, (_sign)), \

	AD7266_CHAN(5, (_sign)), \

	AD7266_CHAN(6, (_sign)), \

	AD7266_CHAN(7, (_sign)), \

	AD7266_CHAN(8, (_sign)), \

	AD7266_CHAN(9, (_sign)), \

	AD7266_CHAN(10, (_sign)), \

	AD7266_CHAN(11, (_sign)), \

	IIO_CHAN_SOFT_TIMESTAMP(13), \

}



#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \

const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \

	AD7266_CHAN(0, (_sign)), \

	AD7266_CHAN(1, (_sign)), \

	IIO_CHAN_SOFT_TIMESTAMP(2), \

}



static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');

static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');

static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');

static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');



#define AD7266_CHAN_DIFF(_chan, _sign) {			\

	.type = IIO_VOLTAGE,				\

	.indexed = 1,					\

	.channel = (_chan) * 2,				\

	.channel2 = (_chan) * 2 + 1,			\

	.address = (_chan),				\

	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT	\

		| IIO_CHAN_INFO_SCALE_SHARED_BIT	\

		| IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\

	.scan_index = (_chan),				\

	.scan_type = {					\

		.sign = _sign,			\

		.realbits = 12,				\

		.storagebits = 16,			\

		.shift = 2,				\

		.endianness = IIO_BE,			\

	},						\

	.differential = 1,				\

}



#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \

const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \

	AD7266_CHAN_DIFF(0, (_sign)), \

	AD7266_CHAN_DIFF(1, (_sign)), \

	AD7266_CHAN_DIFF(2, (_sign)), \

	AD7266_CHAN_DIFF(3, (_sign)), \

	AD7266_CHAN_DIFF(4, (_sign)), \

	AD7266_CHAN_DIFF(5, (_sign)), \

	IIO_CHAN_SOFT_TIMESTAMP(6), \

}



static AD7266_DECLARE_DIFF_CHANNELS(s, 's');

static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');



#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \

const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \

	AD7266_CHAN_DIFF(0, (_sign)), \

	AD7266_CHAN_DIFF(1, (_sign)), \

	IIO_CHAN_SOFT_TIMESTAMP(2), \

}



static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');

static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');



static const struct iio_info ad7266_info = {

	.read_raw = &ad7266_read_raw,

	.update_scan_mode = &ad7266_update_scan_mode,

	.driver_module = THIS_MODULE,

};



static unsigned long ad7266_available_scan_masks[] = {

	0x003,

	0x00c,

	0x030,

	0x0c0,

	0x300,

	0xc00,

	0x000,

};



static unsigned long ad7266_available_scan_masks_diff[] = {

	0x003,

	0x00c,

	0x030,

	0x000,

};



static unsigned long ad7266_available_scan_masks_fixed[] = {

	0x003,

	0x000,

};



struct ad7266_chan_info {

	const struct iio_chan_spec *channels;

	unsigned int num_channels;

	unsigned long *scan_masks;

};



#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \

	(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))



static const struct ad7266_chan_info ad7266_chan_infos[] = {

	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {

		.channels = ad7266_channels_u,

		.num_channels = ARRAY_SIZE(ad7266_channels_u),

		.scan_masks = ad7266_available_scan_masks,

	},

	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {

		.channels = ad7266_channels_u_fixed,

		.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),

		.scan_masks = ad7266_available_scan_masks_fixed,

	},

	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {

		.channels = ad7266_channels_s,

		.num_channels = ARRAY_SIZE(ad7266_channels_s),

		.scan_masks = ad7266_available_scan_masks,

	},

	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {

		.channels = ad7266_channels_s_fixed,

		.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),

		.scan_masks = ad7266_available_scan_masks_fixed,

	},

	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {

		.channels = ad7266_channels_diff_u,

		.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),

		.scan_masks = ad7266_available_scan_masks_diff,

	},

	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {

		.channels = ad7266_channels_diff_fixed_u,

		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),

		.scan_masks = ad7266_available_scan_masks_fixed,

	},

	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {

		.channels = ad7266_channels_diff_s,

		.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),

		.scan_masks = ad7266_available_scan_masks_diff,

	},

	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {

		.channels = ad7266_channels_diff_fixed_s,

		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),

		.scan_masks = ad7266_available_scan_masks_fixed,

	},

};



static void __devinit ad7266_init_channels(struct iio_dev *indio_dev)

{

	struct ad7266_state *st = iio_priv(indio_dev);

	bool is_differential, is_signed;

	const struct ad7266_chan_info *chan_info;

	int i;



	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;

	is_signed = (st->range == AD7266_RANGE_2VREF) |

		    (st->mode == AD7266_MODE_DIFF);



	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);

	chan_info = &ad7266_chan_infos[i];



	indio_dev->channels = chan_info->channels;

	indio_dev->num_channels = chan_info->num_channels;

	indio_dev->available_scan_masks = chan_info->scan_masks;

	indio_dev->masklength = chan_info->num_channels - 1;

}



static const char * const ad7266_gpio_labels[] = {

	"AD0", "AD1", "AD2",

};



static int __devinit ad7266_probe(struct spi_device *spi)

{

	struct ad7266_platform_data *pdata = spi->dev.platform_data;

	struct iio_dev *indio_dev;

	struct ad7266_state *st;

	unsigned int i;

	int ret;



	indio_dev = iio_device_alloc(sizeof(*st));

	if (indio_dev == NULL)

		return -ENOMEM;



	st = iio_priv(indio_dev);



	st->reg = regulator_get(&spi->dev, "vref");

	if (!IS_ERR_OR_NULL(st->reg)) {

		ret = regulator_enable(st->reg);

		if (ret)

			goto error_put_reg;



		st->vref_uv = regulator_get_voltage(st->reg);

	} else {

		/* Use internal reference */

		st->vref_uv = 2500000;

	}



	if (pdata) {

		st->fixed_addr = pdata->fixed_addr;

		st->mode = pdata->mode;

		st->range = pdata->range;



		if (!st->fixed_addr) {

			for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {

				st->gpios[i].gpio = pdata->addr_gpios[i];

				st->gpios[i].flags = GPIOF_OUT_INIT_LOW;

				st->gpios[i].label = ad7266_gpio_labels[i];

			}

			ret = gpio_request_array(st->gpios,

				ARRAY_SIZE(st->gpios));

			if (ret)

				goto error_disable_reg;

		}

	} else {

		st->fixed_addr = true;

		st->range = AD7266_RANGE_VREF;

		st->mode = AD7266_MODE_DIFF;

	}



	spi_set_drvdata(spi, indio_dev);

	st->spi = spi;



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

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

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->info = &ad7266_info;



	ad7266_init_channels(indio_dev);



	/* wakeup */

	st->single_xfer[0].rx_buf = &st->data;

	st->single_xfer[0].len = 2;

	st->single_xfer[0].cs_change = 1;

	/* conversion */

	st->single_xfer[1].rx_buf = &st->data;

	st->single_xfer[1].len = 4;

	st->single_xfer[1].cs_change = 1;

	/* powerdown */

	st->single_xfer[2].tx_buf = &st->data;

	st->single_xfer[2].len = 1;



	spi_message_init(&st->single_msg);

	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);

	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);

	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);



	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,

		&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);

	if (ret)

		goto error_free_gpios;



	ret = iio_device_register(indio_dev);

	if (ret)

		goto error_buffer_cleanup;



	return 0;



error_buffer_cleanup:

	iio_triggered_buffer_cleanup(indio_dev);

error_free_gpios:

	if (!st->fixed_addr)

		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));

error_disable_reg:

	if (!IS_ERR_OR_NULL(st->reg))

		regulator_disable(st->reg);

error_put_reg:

	if (!IS_ERR_OR_NULL(st->reg))

		regulator_put(st->reg);



	iio_device_free(indio_dev);



	return ret;

}



static int __devexit ad7266_remove(struct spi_device *spi)

{

	struct iio_dev *indio_dev = spi_get_drvdata(spi);

	struct ad7266_state *st = iio_priv(indio_dev);



	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);

	if (!st->fixed_addr)

		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));

	if (!IS_ERR_OR_NULL(st->reg)) {

		regulator_disable(st->reg);

		regulator_put(st->reg);

	}

	iio_device_free(indio_dev);



	return 0;

}



static const struct spi_device_id ad7266_id[] = {

	{"ad7265", 0},

	{"ad7266", 0},

	{ }

};

MODULE_DEVICE_TABLE(spi, ad7266_id);



static struct spi_driver ad7266_driver = {

	.driver = {

		.name	= "ad7266",

		.owner	= THIS_MODULE,

	},

	.probe		= ad7266_probe,

	.remove		= __devexit_p(ad7266_remove),

	.id_table	= ad7266_id,

};

module_spi_driver(ad7266_driver);



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

MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");

MODULE_LICENSE("GPL v2");

include/linux/platform_data/ad7266.h

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/*

 * AD7266/65 SPI ADC driver

 *

 * Copyright 2012 Analog Devices Inc.

 *

 * Licensed under the GPL-2.

 */



#ifndef __IIO_ADC_AD7266_H__

#define __IIO_ADC_AD7266_H__



/**

 * enum ad7266_range - AD7266 reference voltage range

 * @AD7266_RANGE_VREF: Device is configured for input range 0V - VREF

 *			(RANGE pin set to low)

 * @AD7266_RANGE_2VREF: Device is configured for input range 0V - 2VREF

 *			(RANGE pin set to high)

 */

enum ad7266_range {

	AD7266_RANGE_VREF,

	AD7266_RANGE_2VREF,

};



/**

 * enum ad7266_mode - AD7266 sample mode

 * @AD7266_MODE_DIFF: Device is configured for full differential mode

 *				(SGL/DIFF pin set to low, AD0 pin set to low)

 * @AD7266_MODE_PSEUDO_DIFF: Device is configured for pseudo differential mode

 *				(SGL/DIFF pin set to low, AD0 pin set to high)

 * @AD7266_MODE_SINGLE_ENDED: Device is configured for single-ended mode

 *				(SGL/DIFF pin set to high)

 */

enum ad7266_mode {

	AD7266_MODE_DIFF,

	AD7266_MODE_PSEUDO_DIFF,

	AD7266_MODE_SINGLE_ENDED,

};



/**

 * struct ad7266_platform_data - Platform data for the AD7266 driver

 * @range: Reference voltage range the device is configured for

 * @mode: Sample mode the device is configured for

 * @fixed_addr: Whether the address pins are hard-wired

 * @addr_gpios: GPIOs used for controlling the address pins, only used if

 *		fixed_addr is set to false.

 */

struct ad7266_platform_data {

	enum ad7266_range range;

	enum ad7266_mode mode;

	bool fixed_addr;

	unsigned int addr_gpios[3];

};



#endif