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Commit fc167f62 authored by Philippe Reynes's avatar Philippe Reynes Committed by Jonathan Cameron
Browse files

iio: add support of the max1027 



This driver add partial support of the
maxim 1027/1029/1031. Differential mode is not
supported.

It was tested on armadeus apf27 board.

Signed-off-by: default avatarPhilippe Reynes <tremyfr@yahoo.fr>
Reviewed-by: default avatarHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent b9785535

Documentation/devicetree/bindings/iio/adc/max1027-adc.txt

0 → 100644
+22 −0
Original line number Diff line number Diff line 
* Maxim 1027/1029/1031 Analog to Digital Converter (ADC)



Required properties:

  - compatible: Should be "maxim,max1027" or "maxim,max1029" or "maxim,max1031"

  - reg: SPI chip select number for the device

  - interrupt-parent: phandle to the parent interrupt controller

  see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt

  - interrupts: IRQ line for the ADC

  see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt



Recommended properties:

- spi-max-frequency: Definition as per

                     Documentation/devicetree/bindings/spi/spi-bus.txt



Example:

adc@0 {

	compatible = "maxim,max1027";

	reg = <0>;

	interrupt-parent = <&gpio5>;

	interrupts = <15 IRQ_TYPE_EDGE_RISING>;

	spi-max-frequency = <1000000>;

};

drivers/iio/adc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -131,6 +131,15 @@ config LP8788_ADC 
	help

	  Say yes here to build support for TI LP8788 ADC.



config MAX1027

	tristate "Maxim max1027 ADC driver"

	depends on SPI

	select IIO_BUFFER

	select IIO_TRIGGERED_BUFFER

	help

	  Say yes here to build support for Maxim SPI ADC models

	  max1027, max1029 and max1031.



config MAX1363

	tristate "Maxim max1363 ADC driver"

	depends on I2C

drivers/iio/adc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ obj-$(CONFIG_AD799X) += ad799x.o 
obj-$(CONFIG_AT91_ADC) += at91_adc.o

obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o

obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o

obj-$(CONFIG_MAX1027) += max1027.o

obj-$(CONFIG_MAX1363) += max1363.o

obj-$(CONFIG_MCP320X) += mcp320x.o

obj-$(CONFIG_MCP3422) += mcp3422.o

drivers/iio/adc/max1027.c

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+521 −0
Original line number Diff line number Diff line 
 /*

  * iio/adc/max1027.c

  * Copyright (C) 2014 Philippe Reynes

  *

  * based on linux/drivers/iio/ad7923.c

  * Copyright 2011 Analog Devices Inc (from AD7923 Driver)

  * Copyright 2012 CS Systemes d'Information

  *

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

  * it under the terms of the GNU General Public License version 2 as

  * published by the Free Software Foundation.

  *

  * max1027.c

  *

  * Partial support for max1027 and similar chips.

  */



#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/spi/spi.h>

#include <linux/delay.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>



#define MAX1027_CONV_REG  BIT(7)

#define MAX1027_SETUP_REG BIT(6)

#define MAX1027_AVG_REG   BIT(5)

#define MAX1027_RST_REG   BIT(4)



/* conversion register */

#define MAX1027_TEMP      BIT(0)

#define MAX1027_SCAN_0_N  (0x00 << 1)

#define MAX1027_SCAN_N_M  (0x01 << 1)

#define MAX1027_SCAN_N    (0x02 << 1)

#define MAX1027_NOSCAN    (0x03 << 1)

#define MAX1027_CHAN(n)   ((n) << 3)



/* setup register */

#define MAX1027_UNIPOLAR  0x02

#define MAX1027_BIPOLAR   0x03

#define MAX1027_REF_MODE0 (0x00 << 2)

#define MAX1027_REF_MODE1 (0x01 << 2)

#define MAX1027_REF_MODE2 (0x02 << 2)

#define MAX1027_REF_MODE3 (0x03 << 2)

#define MAX1027_CKS_MODE0 (0x00 << 4)

#define MAX1027_CKS_MODE1 (0x01 << 4)

#define MAX1027_CKS_MODE2 (0x02 << 4)

#define MAX1027_CKS_MODE3 (0x03 << 4)



/* averaging register */

#define MAX1027_NSCAN_4   0x00

#define MAX1027_NSCAN_8   0x01

#define MAX1027_NSCAN_12  0x02

#define MAX1027_NSCAN_16  0x03

#define MAX1027_NAVG_4    (0x00 << 2)

#define MAX1027_NAVG_8    (0x01 << 2)

#define MAX1027_NAVG_16   (0x02 << 2)

#define MAX1027_NAVG_32   (0x03 << 2)

#define MAX1027_AVG_EN    BIT(4)



enum max1027_id {

	max1027,

	max1029,

	max1031,

};



static const struct spi_device_id max1027_id[] = {

	{"max1027", max1027},

	{"max1029", max1029},

	{"max1031", max1031},

	{}

};

MODULE_DEVICE_TABLE(spi, max1027_id);



#ifdef CONFIG_OF

static const struct of_device_id max1027_adc_dt_ids[] = {

	{ .compatible = "maxim,max1027" },

	{ .compatible = "maxim,max1029" },

	{ .compatible = "maxim,max1031" },

	{},

};

MODULE_DEVICE_TABLE(of, max1027_adc_dt_ids);

#endif



#define MAX1027_V_CHAN(index)						\

	{								\

		.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),	\

		.scan_index = index + 1,				\

		.scan_type = {						\

			.sign = 'u',					\

			.realbits = 10,					\

			.storagebits = 16,				\

			.shift = 2,					\

			.endianness = IIO_BE,				\

		},							\

	}



#define MAX1027_T_CHAN							\

	{								\

		.type = IIO_TEMP,					\

		.channel = 0,						\

		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\

		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\

		.scan_index = 0,					\

		.scan_type = {						\

			.sign = 'u',					\

			.realbits = 12,					\

			.storagebits = 16,				\

			.endianness = IIO_BE,				\

		},							\

	}



static const struct iio_chan_spec max1027_channels[] = {

	MAX1027_T_CHAN,

	MAX1027_V_CHAN(0),

	MAX1027_V_CHAN(1),

	MAX1027_V_CHAN(2),

	MAX1027_V_CHAN(3),

	MAX1027_V_CHAN(4),

	MAX1027_V_CHAN(5),

	MAX1027_V_CHAN(6),

	MAX1027_V_CHAN(7)

};



static const struct iio_chan_spec max1029_channels[] = {

	MAX1027_T_CHAN,

	MAX1027_V_CHAN(0),

	MAX1027_V_CHAN(1),

	MAX1027_V_CHAN(2),

	MAX1027_V_CHAN(3),

	MAX1027_V_CHAN(4),

	MAX1027_V_CHAN(5),

	MAX1027_V_CHAN(6),

	MAX1027_V_CHAN(7),

	MAX1027_V_CHAN(8),

	MAX1027_V_CHAN(9),

	MAX1027_V_CHAN(10),

	MAX1027_V_CHAN(11)

};



static const struct iio_chan_spec max1031_channels[] = {

	MAX1027_T_CHAN,

	MAX1027_V_CHAN(0),

	MAX1027_V_CHAN(1),

	MAX1027_V_CHAN(2),

	MAX1027_V_CHAN(3),

	MAX1027_V_CHAN(4),

	MAX1027_V_CHAN(5),

	MAX1027_V_CHAN(6),

	MAX1027_V_CHAN(7),

	MAX1027_V_CHAN(8),

	MAX1027_V_CHAN(9),

	MAX1027_V_CHAN(10),

	MAX1027_V_CHAN(11),

	MAX1027_V_CHAN(12),

	MAX1027_V_CHAN(13),

	MAX1027_V_CHAN(14),

	MAX1027_V_CHAN(15)

};



static const unsigned long max1027_available_scan_masks[] = {

	0x000001ff,

	0x00000000,

};



static const unsigned long max1029_available_scan_masks[] = {

	0x00001fff,

	0x00000000,

};



static const unsigned long max1031_available_scan_masks[] = {

	0x0001ffff,

	0x00000000,

};



struct max1027_chip_info {

	const struct iio_chan_spec *channels;

	unsigned int num_channels;

	const unsigned long *available_scan_masks;

};



static const struct max1027_chip_info max1027_chip_info_tbl[] = {

	[max1027] = {

		.channels = max1027_channels,

		.num_channels = ARRAY_SIZE(max1027_channels),

		.available_scan_masks = max1027_available_scan_masks,

	},

	[max1029] = {

		.channels = max1029_channels,

		.num_channels = ARRAY_SIZE(max1029_channels),

		.available_scan_masks = max1029_available_scan_masks,

	},

	[max1031] = {

		.channels = max1031_channels,

		.num_channels = ARRAY_SIZE(max1031_channels),

		.available_scan_masks = max1031_available_scan_masks,

	},

};



struct max1027_state {

	const struct max1027_chip_info	*info;

	struct spi_device		*spi;

	struct iio_trigger		*trig;

	__be16				*buffer;

	struct mutex			lock;



	u8				reg ____cacheline_aligned;

};



static int max1027_read_single_value(struct iio_dev *indio_dev,

				     struct iio_chan_spec const *chan,

				     int *val)

{

	int ret;

	struct max1027_state *st = iio_priv(indio_dev);



	if (iio_buffer_enabled(indio_dev)) {

		dev_warn(&indio_dev->dev, "trigger mode already enabled");

		return -EBUSY;

	}



	/* Start acquisition on conversion register write */

	st->reg = MAX1027_SETUP_REG | MAX1027_REF_MODE2 | MAX1027_CKS_MODE2;

	ret = spi_write(st->spi, &st->reg, 1);

	if (ret < 0) {

		dev_err(&indio_dev->dev,

			"Failed to configure setup register\n");

		return ret;

	}



	/* Configure conversion register with the requested chan */

	st->reg = MAX1027_CONV_REG | MAX1027_CHAN(chan->channel) |

		  MAX1027_NOSCAN | !!(chan->type == IIO_TEMP);

	ret = spi_write(st->spi, &st->reg, 1);

	if (ret < 0) {

		dev_err(&indio_dev->dev,

			"Failed to configure conversion register\n");

		return ret;

	}



	/*

	 * For an unknown reason, when we use the mode "10" (write

	 * conversion register), the interrupt doesn't occur every time.

	 * So we just wait 1 ms.

	 */

	mdelay(1);



	/* Read result */

	ret = spi_read(st->spi, st->buffer, (chan->type == IIO_TEMP) ? 4 : 2);

	if (ret < 0)

		return ret;



	*val = be16_to_cpu(st->buffer[0]);



	return IIO_VAL_INT;

}



static int max1027_read_raw(struct iio_dev *indio_dev,

			    struct iio_chan_spec const *chan,

			    int *val, int *val2, long mask)

{

	int ret = 0;

	struct max1027_state *st = iio_priv(indio_dev);



	mutex_lock(&st->lock);



	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		ret = max1027_read_single_value(indio_dev, chan, val);

		break;

	case IIO_CHAN_INFO_SCALE:

		switch (chan->type) {

		case IIO_TEMP:

			*val = 1;

			*val2 = 8;

			ret = IIO_VAL_FRACTIONAL;

			break;

		case IIO_VOLTAGE:

			*val = 2500;

			*val2 = 10;

			ret = IIO_VAL_FRACTIONAL_LOG2;

			break;

		default:

			ret = -EINVAL;

			break;

		}

		break;

	default:

		ret = -EINVAL;

		break;

	}



	mutex_unlock(&st->lock);



	return ret;

}



static int max1027_debugfs_reg_access(struct iio_dev *indio_dev,

				      unsigned reg, unsigned writeval,

				      unsigned *readval)

{

	struct max1027_state *st = iio_priv(indio_dev);

	u8 *val = (u8 *)st->buffer;



	if (readval != NULL)

		return -EINVAL;



	*val = (u8)writeval;

	return spi_write(st->spi, val, 1);

}



static int max1027_validate_trigger(struct iio_dev *indio_dev,

				    struct iio_trigger *trig)

{

	struct max1027_state *st = iio_priv(indio_dev);



	if (st->trig != trig)

		return -EINVAL;



	return 0;

}



static int max1027_set_trigger_state(struct iio_trigger *trig, bool state)

{

	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);

	struct max1027_state *st = iio_priv(indio_dev);

	int ret;



	if (state) {

		/* Start acquisition on cnvst */

		st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE0 |

			  MAX1027_REF_MODE2;

		ret = spi_write(st->spi, &st->reg, 1);

		if (ret < 0)

			return ret;



		/* Scan from 0 to max */

		st->reg = MAX1027_CONV_REG | MAX1027_CHAN(0) |

			  MAX1027_SCAN_N_M | MAX1027_TEMP;

		ret = spi_write(st->spi, &st->reg, 1);

		if (ret < 0)

			return ret;

	} else {

		/* Start acquisition on conversion register write */

		st->reg = MAX1027_SETUP_REG | MAX1027_CKS_MODE2	|

			  MAX1027_REF_MODE2;

		ret = spi_write(st->spi, &st->reg, 1);

		if (ret < 0)

			return ret;

	}



	return 0;

}



static int max1027_validate_device(struct iio_trigger *trig,

				   struct iio_dev *indio_dev)

{

	struct iio_dev *indio = iio_trigger_get_drvdata(trig);



	if (indio != indio_dev)

		return -EINVAL;



	return 0;

}



static irqreturn_t max1027_trigger_handler(int irq, void *private)

{

	struct iio_poll_func *pf = (struct iio_poll_func *)private;

	struct iio_dev *indio_dev = pf->indio_dev;

	struct max1027_state *st = iio_priv(indio_dev);



	pr_debug("%s(irq=%d, private=0x%p)\n", __func__, irq, private);



	/* fill buffer with all channel */

	spi_read(st->spi, st->buffer, indio_dev->masklength * 2);



	iio_push_to_buffers(indio_dev, st->buffer);



	iio_trigger_notify_done(indio_dev->trig);



	return IRQ_HANDLED;

}



static const struct iio_trigger_ops max1027_trigger_ops = {

	.owner = THIS_MODULE,

	.validate_device = &max1027_validate_device,

	.set_trigger_state = &max1027_set_trigger_state,

};



static const struct iio_info max1027_info = {

	.driver_module = THIS_MODULE,

	.read_raw = &max1027_read_raw,

	.validate_trigger = &max1027_validate_trigger,

	.debugfs_reg_access = &max1027_debugfs_reg_access,

};



static int max1027_probe(struct spi_device *spi)

{

	int ret;

	struct iio_dev *indio_dev;

	struct max1027_state *st;



	pr_debug("%s: probe(spi = 0x%p)\n", __func__, spi);



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

	if (indio_dev == NULL) {

		pr_err("Can't allocate iio device\n");

		return -ENOMEM;

	}



	spi_set_drvdata(spi, indio_dev);



	st = iio_priv(indio_dev);

	st->spi = spi;

	st->info = &max1027_chip_info_tbl[spi_get_device_id(spi)->driver_data];



	mutex_init(&st->lock);



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

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

	indio_dev->info = &max1027_info;

	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = st->info->channels;

	indio_dev->num_channels = st->info->num_channels;

	indio_dev->available_scan_masks = st->info->available_scan_masks;



	st->buffer = devm_kmalloc(&indio_dev->dev,

				  indio_dev->num_channels * 2,

				  GFP_KERNEL);

	if (st->buffer == NULL) {

		dev_err(&indio_dev->dev, "Can't allocate bufffer\n");

		return -ENOMEM;

	}



	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,

					 &max1027_trigger_handler, NULL);

	if (ret < 0) {

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

		return ret;

	}



	st->trig = devm_iio_trigger_alloc(&spi->dev, "%s-trigger",

							indio_dev->name);

	if (st->trig == NULL) {

		ret = -ENOMEM;

		dev_err(&indio_dev->dev, "Failed to allocate iio trigger\n");

		goto fail_trigger_alloc;

	}



	st->trig->ops = &max1027_trigger_ops;

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

	iio_trigger_set_drvdata(st->trig, indio_dev);

	iio_trigger_register(st->trig);



	ret = devm_request_threaded_irq(&spi->dev, spi->irq,

					iio_trigger_generic_data_rdy_poll,

					NULL,

					IRQF_TRIGGER_FALLING,

					spi->dev.driver->name, st->trig);

	if (ret < 0) {

		dev_err(&indio_dev->dev, "Failed to allocate IRQ.\n");

		goto fail_dev_register;

	}



	/* Disable averaging */

	st->reg = MAX1027_AVG_REG;

	ret = spi_write(st->spi, &st->reg, 1);

	if (ret < 0) {

		dev_err(&indio_dev->dev, "Failed to configure averaging register\n");

		goto fail_dev_register;

	}



	ret = iio_device_register(indio_dev);

	if (ret < 0) {

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

		goto fail_dev_register;

	}



	return 0;



fail_dev_register:

fail_trigger_alloc:

	iio_triggered_buffer_cleanup(indio_dev);



	return ret;

}



static int max1027_remove(struct spi_device *spi)

{

	struct iio_dev *indio_dev = spi_get_drvdata(spi);



	pr_debug("%s: remove(spi = 0x%p)\n", __func__, spi);



	iio_device_unregister(indio_dev);

	iio_triggered_buffer_cleanup(indio_dev);



	return 0;

}



static struct spi_driver max1027_driver = {

	.driver = {

		.name	= "max1027",

		.owner	= THIS_MODULE,

	},

	.probe		= max1027_probe,

	.remove		= max1027_remove,

	.id_table	= max1027_id,

};

module_spi_driver(max1027_driver);



MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");

MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");

MODULE_LICENSE("GPL v2");