Re: [PATCH v7] iio: add support of the max1027

[Jonathan Cameron]

On June 23, 2014 10:08:15 AM GMT+01:00, Hartmut Knaack <knaack.h@xxxxxx> wrote:
>Philippe Reynes schrieb:
>> 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: Philippe Reynes <tremyfr@xxxxxxxx>
>Reviewed-by: Hartmut Knaack <knaack.h@xxxxxx>
>> ---
>Not sure if it's too late, already. Looks pretty good to me, no
>show-stoppers. Though 3 minor issues inline, comments welcome.
>>  .../devicetree/bindings/iio/adc/max1027-adc.txt    |   22 +
>>  drivers/iio/adc/Kconfig                            |    9 +
>>  drivers/iio/adc/Makefile                           |    1 +
>>  drivers/iio/adc/max1027.c                          |  521
>++++++++++++++++++++
>>  4 files changed, 553 insertions(+), 0 deletions(-)
>>  create mode 100644
>Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
>>  create mode 100644 drivers/iio/adc/max1027.c
>>
>> Changelog:
>> v7: (thanks Hartmut Knaack and Jonathan Cameron for the feedback)
>> - use const with info in max1027_state
>> - use bitops.h (and BIT)
>> - separate operators with whitespace
>> - define a reg member in max1027_state
>>
>> v6: (thanks Peter Meerwald for the feedback)
>> - dont use index with temperature
>> - use const on scan mask
>> - use __be16 * for buffer
>> - return -EBUSY if trigger is already running
>> - replace it by interrupt in comment
>> - dont finish case with ";"
>> - use iio_push_to_buffers
>> - remove useless initialization of st->buffer
>> - remove useless obvious comment
>>
>> v5: (thanks Jonathan Cameron for the feedback)
>> - add validate_trigger
>> - add validate_device
>> - remove useless (void *) cast
>> - use allocated buffer for spi_write
>>
>> v4: (thanks Jonathan Cameron for the feedback)
>> - use iio_trigger_generic_data_rdy_poll
>>
>> v3: (thanks Hartmut Knaack, Lars-Peter Clausen and Jonathan Cameron
>for the feedback)
>> - move to drivers/iio/adc (was in staging)
>> - clean binding doc
>> - drop empty update_scan_mode callback
>> - add a lock around single channel read code
>> - remove useless wrappers around spi_write and spi_read
>> - fix available scan mask (a bit was missing)
>> - remove useless header
>> - some others little cleanp
>>
>> v2: (thanks Hartmut Knaack and Jonathan Cameron for the feedback)
>> - really use devm_* 
>> - use demux magic
>> - use spi_read and spi_write (instead of spi_sync)
>> - use define for register (instead of hardcoded value)
>>
>> diff --git
>a/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
>b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
>> new file mode 100644
>> index 0000000..a8770cc
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/max1027-adc.txt
>> @@ -0,0 +1,22 @@
>> +* 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>;
>> +};
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index a80d236..20a7073 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -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
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 9d60f2d..38cf5c3 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -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
>> diff --git a/drivers/iio/adc/max1027.c b/drivers/iio/adc/max1027.c
>> new file mode 100644
>> index 0000000..87ee1c7
>> --- /dev/null
>> +++ b/drivers/iio/adc/max1027.c
>> @@ -0,0 +1,521 @@
>> + /*
>> +  * 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;
>Why is it necessary to align a single byte variable? Even if the
>compiler pads and aligns it to the architectures optimum size and
>position, I don't see how it could wrap to another cacheline.

Issue is not that. Point is to prevent DMA yo this variable resulting in other bits of the structure getting overwritten.
>> +};
>> +
>> +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;
>No big deal, but I don't see, how this break is ever reached. ^^
>> +	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:
>One of the labels could be dropped.
>> +	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@xxxxxxxx>");
>> +MODULE_DESCRIPTION("MAX1027/MAX1029/MAX1031 ADC");
>> +MODULE_LICENSE("GPL v2");

-- 
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