Commit 902c4b24 authored by David Lechner's avatar David Lechner Committed by Jonathan Cameron
Browse files

iio: adc: New driver for TI ADS7950 chips 



This adds a new driver for the TI ADS7950 family of ADC chips. These
communicate using SPI and come in 8/10/12-bit and 4/8/12/16 channel
varieties.

Signed-off-by: default avatarDavid Lechner <david@lechnology.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 071cf249

drivers/iio/adc/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -549,6 +549,19 @@ config TI_ADS1015 
	  This driver can also be built as a module. If so, the module will be

	  called ti-ads1015.



config TI_ADS7950

	tristate "Texas Instruments ADS7950 ADC driver"

	depends on SPI

	select IIO_BUFFER

	select IIO_TRIGGERED_BUFFER

	help

	  Say yes here to build support for Texas Instruments ADS7950, ADS7951,

	  ADS7952, ADS7953, ADS7954, ADS7955, ADS7956, ADS7957, ADS7958, ADS7959.

	  ADS7960, ADS7961.



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

	  module will be called ti-ads7950.



config TI_ADS8688

	tristate "Texas Instruments ADS8688"

	depends on SPI && OF

drivers/iio/adc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o 
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o

obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o

obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o

obj-$(CONFIG_TI_ADS7950) += ti-ads7950.o

obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o

obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o

obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o

drivers/iio/adc/ti-ads7950.c

0 → 100644
+490 −0
Original line number Diff line number Diff line 
/*

 * Texas Instruments ADS7950 SPI ADC driver

 *

 * Copyright 2016 David Lechner <david@lechnology.com>

 *

 * Based on iio/ad7923.c:

 * Copyright 2011 Analog Devices Inc

 * Copyright 2012 CS Systemes d'Information

 *

 * And also on hwmon/ads79xx.c

 * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com/

 *	Nishanth Menon

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/regulator/consumer.h>

#include <linux/slab.h>

#include <linux/spi/spi.h>



#include <linux/iio/buffer.h>

#include <linux/iio/iio.h>

#include <linux/iio/sysfs.h>

#include <linux/iio/trigger_consumer.h>

#include <linux/iio/triggered_buffer.h>



#define TI_ADS7950_CR_MANUAL	BIT(12)

#define TI_ADS7950_CR_WRITE	BIT(11)

#define TI_ADS7950_CR_CHAN(ch)	((ch) << 7)

#define TI_ADS7950_CR_RANGE_5V	BIT(6)



#define TI_ADS7950_MAX_CHAN	16



#define TI_ADS7950_TIMESTAMP_SIZE (sizeof(int64_t) / sizeof(__be16))



/* val = value, dec = left shift, bits = number of bits of the mask */

#define TI_ADS7950_EXTRACT(val, dec, bits) \

	(((val) >> (dec)) & ((1 << (bits)) - 1))



struct ti_ads7950_state {

	struct spi_device	*spi;

	struct spi_transfer	ring_xfer[TI_ADS7950_MAX_CHAN + 2];

	struct spi_transfer	scan_single_xfer[3];

	struct spi_message	ring_msg;

	struct spi_message	scan_single_msg;



	struct regulator	*reg;



	unsigned int		settings;



	/*

	 * DMA (thus cache coherency maintenance) requires the

	 * transfer buffers to live in their own cache lines.

	 */

	__be16	rx_buf[TI_ADS7950_MAX_CHAN + TI_ADS7950_TIMESTAMP_SIZE]

							____cacheline_aligned;

	__be16	tx_buf[TI_ADS7950_MAX_CHAN];

};



struct ti_ads7950_chip_info {

	const struct iio_chan_spec *channels;

	unsigned int num_channels;

};



enum ti_ads7950_id {

	TI_ADS7950,

	TI_ADS7951,

	TI_ADS7952,

	TI_ADS7953,

	TI_ADS7954,

	TI_ADS7955,

	TI_ADS7956,

	TI_ADS7957,

	TI_ADS7958,

	TI_ADS7959,

	TI_ADS7960,

	TI_ADS7961,

};



#define TI_ADS7950_V_CHAN(index, bits)				\

{								\

	.type = IIO_VOLTAGE,					\

	.indexed = 1,						\

	.channel = index,					\

	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\

	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\

	.address = index,					\

	.datasheet_name = "CH##index",				\

	.scan_index = index,					\

	.scan_type = {						\

		.sign = 'u',					\

		.realbits = bits,				\

		.storagebits = 16,				\

		.shift = 12 - (bits),				\

		.endianness = IIO_BE,				\

	},							\

}



#define DECLARE_TI_ADS7950_4_CHANNELS(name, bits) \

const struct iio_chan_spec name ## _channels[] = { \

	TI_ADS7950_V_CHAN(0, bits), \

	TI_ADS7950_V_CHAN(1, bits), \

	TI_ADS7950_V_CHAN(2, bits), \

	TI_ADS7950_V_CHAN(3, bits), \

	IIO_CHAN_SOFT_TIMESTAMP(4), \

}



#define DECLARE_TI_ADS7950_8_CHANNELS(name, bits) \

const struct iio_chan_spec name ## _channels[] = { \

	TI_ADS7950_V_CHAN(0, bits), \

	TI_ADS7950_V_CHAN(1, bits), \

	TI_ADS7950_V_CHAN(2, bits), \

	TI_ADS7950_V_CHAN(3, bits), \

	TI_ADS7950_V_CHAN(4, bits), \

	TI_ADS7950_V_CHAN(5, bits), \

	TI_ADS7950_V_CHAN(6, bits), \

	TI_ADS7950_V_CHAN(7, bits), \

	IIO_CHAN_SOFT_TIMESTAMP(8), \

}



#define DECLARE_TI_ADS7950_12_CHANNELS(name, bits) \

const struct iio_chan_spec name ## _channels[] = { \

	TI_ADS7950_V_CHAN(0, bits), \

	TI_ADS7950_V_CHAN(1, bits), \

	TI_ADS7950_V_CHAN(2, bits), \

	TI_ADS7950_V_CHAN(3, bits), \

	TI_ADS7950_V_CHAN(4, bits), \

	TI_ADS7950_V_CHAN(5, bits), \

	TI_ADS7950_V_CHAN(6, bits), \

	TI_ADS7950_V_CHAN(7, bits), \

	TI_ADS7950_V_CHAN(8, bits), \

	TI_ADS7950_V_CHAN(9, bits), \

	TI_ADS7950_V_CHAN(10, bits), \

	TI_ADS7950_V_CHAN(11, bits), \

	IIO_CHAN_SOFT_TIMESTAMP(12), \

}



#define DECLARE_TI_ADS7950_16_CHANNELS(name, bits) \

const struct iio_chan_spec name ## _channels[] = { \

	TI_ADS7950_V_CHAN(0, bits), \

	TI_ADS7950_V_CHAN(1, bits), \

	TI_ADS7950_V_CHAN(2, bits), \

	TI_ADS7950_V_CHAN(3, bits), \

	TI_ADS7950_V_CHAN(4, bits), \

	TI_ADS7950_V_CHAN(5, bits), \

	TI_ADS7950_V_CHAN(6, bits), \

	TI_ADS7950_V_CHAN(7, bits), \

	TI_ADS7950_V_CHAN(8, bits), \

	TI_ADS7950_V_CHAN(9, bits), \

	TI_ADS7950_V_CHAN(10, bits), \

	TI_ADS7950_V_CHAN(11, bits), \

	TI_ADS7950_V_CHAN(12, bits), \

	TI_ADS7950_V_CHAN(13, bits), \

	TI_ADS7950_V_CHAN(14, bits), \

	TI_ADS7950_V_CHAN(15, bits), \

	IIO_CHAN_SOFT_TIMESTAMP(16), \

}



static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7950, 12);

static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7951, 12);

static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7952, 12);

static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7953, 12);

static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7954, 10);

static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7955, 10);

static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7956, 10);

static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7957, 10);

static DECLARE_TI_ADS7950_4_CHANNELS(ti_ads7958, 8);

static DECLARE_TI_ADS7950_8_CHANNELS(ti_ads7959, 8);

static DECLARE_TI_ADS7950_12_CHANNELS(ti_ads7960, 8);

static DECLARE_TI_ADS7950_16_CHANNELS(ti_ads7961, 8);



static const struct ti_ads7950_chip_info ti_ads7950_chip_info[] = {

	[TI_ADS7950] = {

		.channels	= ti_ads7950_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7950_channels),

	},

	[TI_ADS7951] = {

		.channels	= ti_ads7951_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7951_channels),

	},

	[TI_ADS7952] = {

		.channels	= ti_ads7952_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7952_channels),

	},

	[TI_ADS7953] = {

		.channels	= ti_ads7953_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7953_channels),

	},

	[TI_ADS7954] = {

		.channels	= ti_ads7954_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7954_channels),

	},

	[TI_ADS7955] = {

		.channels	= ti_ads7955_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7955_channels),

	},

	[TI_ADS7956] = {

		.channels	= ti_ads7956_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7956_channels),

	},

	[TI_ADS7957] = {

		.channels	= ti_ads7957_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7957_channels),

	},

	[TI_ADS7958] = {

		.channels	= ti_ads7958_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7958_channels),

	},

	[TI_ADS7959] = {

		.channels	= ti_ads7959_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7959_channels),

	},

	[TI_ADS7960] = {

		.channels	= ti_ads7960_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7960_channels),

	},

	[TI_ADS7961] = {

		.channels	= ti_ads7961_channels,

		.num_channels	= ARRAY_SIZE(ti_ads7961_channels),

	},

};



/*

 * ti_ads7950_update_scan_mode() setup the spi transfer buffer for the new

 * scan mask

 */

static int ti_ads7950_update_scan_mode(struct iio_dev *indio_dev,

				       const unsigned long *active_scan_mask)

{

	struct ti_ads7950_state *st = iio_priv(indio_dev);

	int i, cmd, len;



	len = 0;

	for_each_set_bit(i, active_scan_mask, indio_dev->num_channels) {

		cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(i) | st->settings;

		st->tx_buf[len++] = cpu_to_be16(cmd);

	}



	/* Data for the 1st channel is not returned until the 3rd transfer */

	len += 2;

	for (i = 0; i < len; i++) {

		if ((i + 2) < len)

			st->ring_xfer[i].tx_buf = &st->tx_buf[i];

		if (i >= 2)

			st->ring_xfer[i].rx_buf = &st->rx_buf[i - 2];

		st->ring_xfer[i].len = 2;

		st->ring_xfer[i].cs_change = 1;

	}

	/* make sure last transfer's cs_change is not set */

	st->ring_xfer[len - 1].cs_change = 0;



	spi_message_init_with_transfers(&st->ring_msg, st->ring_xfer, len);



	return 0;

}



static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)

{

	struct iio_poll_func *pf = p;

	struct iio_dev *indio_dev = pf->indio_dev;

	struct ti_ads7950_state *st = iio_priv(indio_dev);

	int ret;



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

	if (ret < 0)

		goto out;



	iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,

					   iio_get_time_ns(indio_dev));



out:

	iio_trigger_notify_done(indio_dev->trig);



	return IRQ_HANDLED;

}



static int ti_ads7950_scan_direct(struct ti_ads7950_state *st, unsigned int ch)

{

	int ret, cmd;



	cmd = TI_ADS7950_CR_WRITE | TI_ADS7950_CR_CHAN(ch) | st->settings;

	st->tx_buf[0] = cpu_to_be16(cmd);



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

	if (ret)

		return ret;



	return be16_to_cpu(st->rx_buf[0]);

}



static int ti_ads7950_get_range(struct ti_ads7950_state *st)

{

	int vref;



	vref = regulator_get_voltage(st->reg);

	if (vref < 0)

		return vref;



	vref /= 1000;



	if (st->settings & TI_ADS7950_CR_RANGE_5V)

		vref *= 2;



	return vref;

}



static int ti_ads7950_read_raw(struct iio_dev *indio_dev,

			       struct iio_chan_spec const *chan,

			       int *val, int *val2, long m)

{

	struct ti_ads7950_state *st = iio_priv(indio_dev);

	int ret;



	switch (m) {

	case IIO_CHAN_INFO_RAW:



		ret = iio_device_claim_direct_mode(indio_dev);

		if (ret < 0)

			return ret;



		ret = ti_ads7950_scan_direct(st, chan->address);

		iio_device_release_direct_mode(indio_dev);

		if (ret < 0)

			return ret;



		if (chan->address != TI_ADS7950_EXTRACT(ret, 12, 4))

			return -EIO;



		*val = TI_ADS7950_EXTRACT(ret, chan->scan_type.shift,

					  chan->scan_type.realbits);



		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		ret = ti_ads7950_get_range(st);

		if (ret < 0)

			return ret;



		*val = ret;

		*val2 = (1 << chan->scan_type.realbits) - 1;



		return IIO_VAL_FRACTIONAL;

	}



	return -EINVAL;

}



static const struct iio_info ti_ads7950_info = {

	.read_raw		= &ti_ads7950_read_raw,

	.update_scan_mode	= ti_ads7950_update_scan_mode,

	.driver_module		= THIS_MODULE,

};



static int ti_ads7950_probe(struct spi_device *spi)

{

	struct ti_ads7950_state *st;

	struct iio_dev *indio_dev;

	const struct ti_ads7950_chip_info *info;

	int ret;



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

	if (!indio_dev)

		return -ENOMEM;



	st = iio_priv(indio_dev);



	spi_set_drvdata(spi, indio_dev);



	st->spi = spi;

	st->settings = TI_ADS7950_CR_MANUAL | TI_ADS7950_CR_RANGE_5V;



	info = &ti_ads7950_chip_info[spi_get_device_id(spi)->driver_data];



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

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

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = info->channels;

	indio_dev->num_channels = info->num_channels;

	indio_dev->info = &ti_ads7950_info;



	/*

	 * Setup default message. The sample is read at the end of the first

	 * transfer, then it takes one full cycle to convert the sample and one

	 * more cycle to send the value. The conversion process is driven by

	 * the SPI clock, which is why we have 3 transfers. The middle one is

	 * just dummy data sent while the chip is converting the sample that

	 * was read at the end of the first transfer.

	 */



	st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];

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

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

	st->scan_single_xfer[1].tx_buf = &st->tx_buf[0];

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

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

	st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];

	st->scan_single_xfer[2].len = 2;



	spi_message_init_with_transfers(&st->scan_single_msg,

					st->scan_single_xfer, 3);



	st->reg = devm_regulator_get(&spi->dev, "refin");

	if (IS_ERR(st->reg)) {

		dev_err(&spi->dev, "Failed get get regulator \"refin\"\n");

		return PTR_ERR(st->reg);

	}



	ret = regulator_enable(st->reg);

	if (ret) {

		dev_err(&spi->dev, "Failed to enable regulator \"refin\"\n");

		return ret;

	}



	ret = iio_triggered_buffer_setup(indio_dev, NULL,

					 &ti_ads7950_trigger_handler, NULL);

	if (ret) {

		dev_err(&spi->dev, "Failed to setup triggered buffer\n");

		goto error_disable_reg;

	}



	ret = iio_device_register(indio_dev);

	if (ret) {

		dev_err(&spi->dev, "Failed to register iio device\n");

		goto error_cleanup_ring;

	}



	return 0;



error_cleanup_ring:

	iio_triggered_buffer_cleanup(indio_dev);

error_disable_reg:

	regulator_disable(st->reg);



	return ret;

}



static int ti_ads7950_remove(struct spi_device *spi)

{

	struct iio_dev *indio_dev = spi_get_drvdata(spi);

	struct ti_ads7950_state *st = iio_priv(indio_dev);



	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);

	regulator_disable(st->reg);



	return 0;

}



static const struct spi_device_id ti_ads7950_id[] = {

	{"ti-ads7950", TI_ADS7950},

	{"ti-ads7951", TI_ADS7951},

	{"ti-ads7952", TI_ADS7952},

	{"ti-ads7953", TI_ADS7953},

	{"ti-ads7954", TI_ADS7954},

	{"ti-ads7955", TI_ADS7955},

	{"ti-ads7956", TI_ADS7956},

	{"ti-ads7957", TI_ADS7957},

	{"ti-ads7958", TI_ADS7958},

	{"ti-ads7959", TI_ADS7959},

	{"ti-ads7960", TI_ADS7960},

	{"ti-ads7961", TI_ADS7961},

	{ }

};

MODULE_DEVICE_TABLE(spi, ti_ads7950_id);



static struct spi_driver ti_ads7950_driver = {

	.driver = {

		.name	= "ti-ads7950",

	},

	.probe		= ti_ads7950_probe,

	.remove		= ti_ads7950_remove,

	.id_table	= ti_ads7950_id,

};

module_spi_driver(ti_ads7950_driver);



MODULE_AUTHOR("David Lechner <david@lechnology.com>");

MODULE_DESCRIPTION("TI TI_ADS7950 ADC");

MODULE_LICENSE("GPL v2");

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