drivers/iio/adc/max1027.c - third_party/linux - Git at Google

  /*
   * 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;
 	if (chan->type == IIO_TEMP)
 		st->reg |= MAX1027_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 irqreturn_t max1027_trigger_handler(int irq, void *private)
 {
 	struct iio_poll_func *pf = 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 = {
 	.validate_device = &iio_trigger_validate_own_device,
 	.set_trigger_state = &max1027_set_trigger_state,
 };

 static const struct iio_info max1027_info = {
 	.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->dev.of_node = spi->dev.of_node;
 	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_array(&indio_dev->dev,
 				  indio_dev->num_channels, 2,
 				  GFP_KERNEL);
 	if (st->buffer == NULL) {
 		dev_err(&indio_dev->dev, "Can't allocate buffer\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;
 	}

 	/* Internal reset */
 	st->reg = MAX1027_RST_REG;
 	ret = spi_write(st->spi, &st->reg, 1);
 	if (ret < 0) {
 		dev_err(&indio_dev->dev, "Failed to reset the ADC\n");
 		return ret;
 	}

 	/* 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",
 		.of_match_table = of_match_ptr(max1027_adc_dt_ids),
 	},
 	.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");
	/*
	* 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;
	if (chan->type == IIO_TEMP)
	st->reg \|= MAX1027_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 irqreturn_t max1027_trigger_handler(int irq, void *private)
	{
	struct iio_poll_func *pf = 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 = {
	.validate_device = &iio_trigger_validate_own_device,
	.set_trigger_state = &max1027_set_trigger_state,
	};

	static const struct iio_info max1027_info = {
	.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->dev.of_node = spi->dev.of_node;
	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_array(&indio_dev->dev,
	indio_dev->num_channels, 2,
	GFP_KERNEL);
	if (st->buffer == NULL) {
	dev_err(&indio_dev->dev, "Can't allocate buffer\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;
	}

	/* Internal reset */
	st->reg = MAX1027_RST_REG;
	ret = spi_write(st->spi, &st->reg, 1);
	if (ret < 0) {
	dev_err(&indio_dev->dev, "Failed to reset the ADC\n");
	return ret;
	}

	/* 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",
	.of_match_table = of_match_ptr(max1027_adc_dt_ids),
	},
	.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");