Re: [PATCH v3 4/4] iio: adc: add support for Allwinner SoCs ADC

[Jonathan Cameron]

On 26/07/16 08:43, Quentin Schulz wrote:
> The Allwinner SoCs all have an ADC that can also act as a touchscreen
> controller and a thermal sensor. This patch adds the ADC driver which is
> based on the MFD for the same SoCs ADC.
> 
> This also registers the thermal adc channel in the iio map array so
> iio_hwmon could use it without modifying the Device Tree. This registers
> the driver in the thermal framework.
> 
> This driver probes on three different platform_device_id to take into
> account slight differences (registers bit and temperature computation)
> between Allwinner SoCs ADCs.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>
> ---
> 
> I don't like how I get the temperature for the thermal framework
> (sunxi_gpadc_get_temp). I am doing the exact same process as the iio_hwmon
> but in this function. This is duplicated code. I could use
> iio_read_channel_processed but it needs to have the iio_channel structure
> of the thermal sensor which I can only get with iio_channel_get which
> matches the device name with the consumer_dev_name in the iio_map array.
> And frankly, I do not see myself declaring the driver both as the producer
> and the consumer of IIO channels.
I also can't see a clean way of reusing the value calculation code.  You
could construct and iio_channel by hand easily enough, but that would be
a pretty ugly bit of 'boundary crossing'.
> 
> Moreover, since the thermal sensor is configured to throw an interrupt
> every X seconds, only the first request within these X seconds will not
> time out. This means that because the thermal framework regularly poll the
> thermal sensor, it is really difficult to get a value from sysfs without
> getting first a tonne of times out. I don't know if we can do something
> about that?
Cache the value what ever read it? (thermal or sysfs) then return that
until a new one shows up...

Otherwise, I don't have anything to add to the other review comments.

Jonathan
> 
> v3:
>  - correct wrapping,
>  - add comment about thermal sensor inner working,
>  - move defines in mfd header,
>  - use structure to define SoC specific registers or behaviour,
>  - attach this structure to the device according to of_device_id of the
>    platform device,
>  - use new mutex instead of iio_dev mutex,
>  - use atomic flags to avoid race between request_irq and disable_irq in
>    probe,
>  - switch from processed value to raw, offset and scale values for
>    temperature ADC channel,
>  - remove faulty sentinel in iio_chan_spec array,
>  - add pm_runtime support,
>  - register thermal sensor in thermal framework (forgotten since the
>    beginning whereas it is present in current sun4i-ts driver),
>  - remove useless ret variables to store return value of regmap_reads,
>  - move comments on thermal sensor acquisition period in code instead of
>    header,
>  - adding goto label to unregister iio_map_array when failing to register
>    iio_dev,
> 
> v2:
>  - add SUNXI_GPADC_ prefixes for defines,
>  - correct typo in Kconfig,
>  - reorder alphabetically includes, makefile,
>  - add license header,
>  - fix architecture variations not being handled in interrupt handlers or
>    read raw functions,
>  - fix unability to return negative values from thermal sensor,
>  - add gotos to reduce code repetition,
>  - fix irq variable being unsigned int instead of int,
>  - remove useless dev_err and dev_info,
>  - deactivate all interrupts if probe fails,
>  - fix iio_device_register on NULL variable,
>  - deactivate ADC in the IP when probe fails or when removing driver,
> 
>  drivers/iio/adc/Kconfig           |  12 +
>  drivers/iio/adc/Makefile          |   1 +
>  drivers/iio/adc/sunxi-gpadc-iio.c | 513 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 526 insertions(+)
>  create mode 100644 drivers/iio/adc/sunxi-gpadc-iio.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 25378c5..429ef16 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -384,6 +384,18 @@ config ROCKCHIP_SARADC
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called rockchip_saradc.
>  
> +config SUN4I_GPADC
> +	tristate "Support for the Allwinner SoCs GPADC"
> +	depends on IIO
> +	depends on MFD_SUN4I_GPADC
> +	help
> +	  Say yes here to build support for Allwinner (A10, A13 and A31) SoCs
> +	  GPADC. This ADC provides 4 channels which can be used as an ADC or as
> +	  a touchscreen input and one channel for thermal sensor.
> +
> +	  To compile this driver as a module, choose M here: the module will be
> +	  called sunxi-gpadc-iio.
> +
>  config TI_ADC081C
>  	tristate "Texas Instruments ADC081C/ADC101C/ADC121C family"
>  	depends on I2C
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 38638d4..14d1739 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
>  obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
>  obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
>  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
> +obj-$(CONFIG_SUN4I_GPADC) += sunxi-gpadc-iio.o
>  obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>  obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>  obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
> diff --git a/drivers/iio/adc/sunxi-gpadc-iio.c b/drivers/iio/adc/sunxi-gpadc-iio.c
> new file mode 100644
> index 0000000..5647688
> --- /dev/null
> +++ b/drivers/iio/adc/sunxi-gpadc-iio.c
> @@ -0,0 +1,513 @@
> +/* ADC driver for sunxi platforms' (A10, A13 and A31) GPADC
> + *
> + * Copyright (c) 2016 Quentin Schulz <quentin.schulz@free-electrons>
> + *
> + * 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.
> + *
> + * The Allwinner SoCs all have an ADC that can also act as a touchscreen
> + * controller and a thermal sensor.
> + * The thermal sensor works only when the ADC acts as a touchscreen controller
> + * and is configured to throw an interrupt every fixed periods of time (let say
> + * every X seconds).
> + * One would be tempted to disable the IP on the hardware side rather than
> + * disabling interrupts to save some power but that reset the internal clock of
> + * the IP, resulting in having to wait X seconds every time we want to read the
> + * value of the thermal sensor.
> + * This is also the reason of using autosuspend in pm_runtime. If there were no
> + * autosuspend, the thermal sensor would need X seconds after every
> + * pm_runtime_get_sync to get a value from the ADC. The autosuspend allows the
> + * thermal sensor to be requested again in a certain time span before it gets
> + * shutdown for not being used.
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/thermal.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/driver.h>
> +#include <linux/iio/machine.h>
> +#include <linux/mfd/sunxi-gpadc-mfd.h>
> +
> +const unsigned int sun4i_gpadc_chan_select(unsigned int chan)
> +{
> +	return SUNXI_GPADC_TP_CTRL1_ADC_CHAN_SELECT(chan);
> +}
> +
> +const unsigned int sun6i_gpadc_chan_select(unsigned int chan)
> +{
> +	return SUNXI_GPADC_TP_CTRL1_SUN6I_ADC_CHAN_SELECT(chan);
> +}
> +
> +struct sunxi_gpadc_soc_specific {
> +	const int		temp_offset;
> +	const int		temp_scale;
> +	const unsigned int	tp_mode_en;
> +	const unsigned int	tp_adc_select;
> +	const unsigned int	(*adc_chan_select)(unsigned int chan);
> +};
> +
> +static const struct sunxi_gpadc_soc_specific sun4i_gpadc_soc_specific = {
> +	.temp_offset = -1932,
> +	.temp_scale = 133,
> +	.tp_mode_en = SUNXI_GPADC_TP_CTRL1_TP_MODE_EN,
> +	.tp_adc_select = SUNXI_GPADC_TP_CTRL1_TP_ADC_SELECT,
> +	.adc_chan_select = &sun4i_gpadc_chan_select,
> +};
> +
> +static const struct sunxi_gpadc_soc_specific sun5i_gpadc_soc_specific = {
> +	.temp_offset = -1447,
> +	.temp_scale = 100,
> +	.tp_mode_en = SUNXI_GPADC_TP_CTRL1_TP_MODE_EN,
> +	.tp_adc_select = SUNXI_GPADC_TP_CTRL1_TP_ADC_SELECT,
> +	.adc_chan_select = &sun4i_gpadc_chan_select,
> +};
> +
> +static const struct sunxi_gpadc_soc_specific sun6i_gpadc_soc_specific = {
> +	.temp_offset = -1623,
> +	.temp_scale = 167,
> +	.tp_mode_en = SUNXI_GPADC_TP_CTRL1_SUN6I_TP_MODE_EN,
> +	.tp_adc_select = SUNXI_GPADC_TP_CTRL1_SUN6I_TP_ADC_SELECT,
> +	.adc_chan_select = &sun6i_gpadc_chan_select,
> +};
> +
> +struct sunxi_gpadc_dev {
> +	struct iio_dev				*indio_dev;
> +	void __iomem				*regs;
> +	struct completion			completion;
> +	int					temp_data;
> +	u32					adc_data;
> +	struct regmap				*regmap;
> +	unsigned int				fifo_data_irq;
> +	atomic_t				ignore_fifo_data_irq;
> +	unsigned int				temp_data_irq;
> +	atomic_t				ignore_temp_data_irq;
> +	const struct sunxi_gpadc_soc_specific	*soc_specific;
> +	struct mutex				mutex;
> +};
> +
> +#define SUNXI_GPADC_ADC_CHANNEL(_channel, _name) {		\
> +	.type = IIO_VOLTAGE,					\
> +	.indexed = 1,						\
> +	.channel = _channel,					\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +	.datasheet_name = _name,				\
> +}
> +
> +static struct iio_map sunxi_gpadc_hwmon_maps[] = {
> +	{
> +		.adc_channel_label = "temp_adc",
> +		.consumer_dev_name = "iio_hwmon.0",
> +	},
> +	{ /* sentinel */ },
> +};
> +
> +static const struct iio_chan_spec sunxi_gpadc_channels[] = {
> +	SUNXI_GPADC_ADC_CHANNEL(0, "adc_chan0"),
> +	SUNXI_GPADC_ADC_CHANNEL(1, "adc_chan1"),
> +	SUNXI_GPADC_ADC_CHANNEL(2, "adc_chan2"),
> +	SUNXI_GPADC_ADC_CHANNEL(3, "adc_chan3"),
> +	{
> +		.type = IIO_TEMP,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE) |
> +				      BIT(IIO_CHAN_INFO_OFFSET),
> +		.datasheet_name = "temp_adc",
> +	},
> +};
> +
> +static int sunxi_gpadc_adc_read(struct iio_dev *indio_dev, int channel,
> +				int *val)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	pm_runtime_get_sync(indio_dev->dev.parent);
> +	mutex_lock(&info->mutex);
> +
> +	reinit_completion(&info->completion);
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL1,
> +		     info->soc_specific->tp_mode_en |
> +		     info->soc_specific->tp_adc_select |
> +		     info->soc_specific->adc_chan_select(channel));
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_INT_FIFOC,
> +		     SUNXI_GPADC_TP_INT_FIFOC_TP_FIFO_TRIG_LEVEL(1) |
> +		     SUNXI_GPADC_TP_INT_FIFOC_TP_FIFO_FLUSH);
> +	enable_irq(info->fifo_data_irq);
> +
> +	if (!wait_for_completion_timeout(&info->completion,
> +					 msecs_to_jiffies(100))) {
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	*val = info->adc_data;
> +
> +out:
> +	disable_irq(info->fifo_data_irq);
> +	mutex_unlock(&info->mutex);
> +	pm_runtime_mark_last_busy(indio_dev->dev.parent);
> +	pm_runtime_put_autosuspend(indio_dev->dev.parent);
> +
> +	return ret;
> +}
> +
> +static int sunxi_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	pm_runtime_get_sync(indio_dev->dev.parent);
> +	mutex_lock(&info->mutex);
> +
> +	reinit_completion(&info->completion);
> +
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_INT_FIFOC,
> +		     SUNXI_GPADC_TP_INT_FIFOC_TP_FIFO_TRIG_LEVEL(1) |
> +		     SUNXI_GPADC_TP_INT_FIFOC_TP_FIFO_FLUSH);
> +	/*
> +	 * The temperature sensor returns valid data only when the ADC operates
> +	 * in touchscreen mode.
> +	 */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL1,
> +		     info->soc_specific->tp_mode_en);
> +	enable_irq(info->temp_data_irq);
> +
> +	if (!wait_for_completion_timeout(&info->completion,
> +					 msecs_to_jiffies(100))) {
> +		ret = -ETIMEDOUT;
> +		goto out;
> +	}
> +
> +	*val = info->temp_data;
> +
> +out:
> +	disable_irq(info->temp_data_irq);
> +	mutex_unlock(&info->mutex);
> +	pm_runtime_mark_last_busy(indio_dev->dev.parent);
> +	pm_runtime_put_autosuspend(indio_dev->dev.parent);
> +
> +	return ret;
> +}
> +
> +static int sunxi_gpadc_temp_offset(struct iio_dev *indio_dev, int *val)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(indio_dev);
> +
> +	*val = info->soc_specific->temp_offset;
> +
> +	return 0;
> +}
> +
> +static int sunxi_gpadc_temp_scale(struct iio_dev *indio_dev, int *val)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(indio_dev);
> +
> +	*val = info->soc_specific->temp_scale;
> +
> +	return 0;
> +}
> +
> +static int sunxi_gpadc_read_raw(struct iio_dev *indio_dev,
> +				struct iio_chan_spec const *chan, int *val,
> +				int *val2, long mask)
> +{
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_OFFSET:
> +		ret = sunxi_gpadc_temp_offset(indio_dev, val);
> +		if (ret)
> +			return ret;
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_RAW:
> +		if (chan->type == IIO_VOLTAGE) {
> +			ret = sunxi_gpadc_adc_read(indio_dev, chan->channel,
> +						   val);
> +			if (ret)
> +				return ret;
> +		} else {
> +			ret = sunxi_gpadc_temp_read(indio_dev, val);
> +			if (ret)
> +				return ret;
> +		}
> +
> +		return IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		ret = sunxi_gpadc_temp_scale(indio_dev, val);
> +		if (ret)
> +			return ret;
> +
> +		return IIO_VAL_INT;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info sunxi_gpadc_iio_info = {
> +	.read_raw = sunxi_gpadc_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static irqreturn_t sunxi_gpadc_temp_data_irq_handler(int irq, void *dev_id)
> +{
> +	struct sunxi_gpadc_dev *info = dev_id;
> +
> +	if (atomic_read(&info->ignore_temp_data_irq))
> +		return IRQ_HANDLED;
> +
> +	if (!regmap_read(info->regmap, SUNXI_GPADC_TEMP_DATA, &info->temp_data))
> +		complete(&info->completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t sunxi_gpadc_fifo_data_irq_handler(int irq, void *dev_id)
> +{
> +	struct sunxi_gpadc_dev *info = dev_id;
> +
> +	if (atomic_read(&info->ignore_fifo_data_irq))
> +		return IRQ_HANDLED;
> +
> +	if (!regmap_read(info->regmap, SUNXI_GPADC_TP_DATA, &info->adc_data))
> +		complete(&info->completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int sunxi_gpadc_runtime_suspend(struct device *dev)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(dev_get_drvdata(dev));
> +
> +	mutex_lock(&info->mutex);
> +
> +	/* Disable the ADC on IP */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL1, 0);
> +	/* Disable temperature sensor on IP */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_TPR, 0);
> +
> +	mutex_unlock(&info->mutex);
> +
> +	return 0;
> +}
> +
> +static int sunxi_gpadc_runtime_resume(struct device *dev)
> +{
> +	struct sunxi_gpadc_dev *info = iio_priv(dev_get_drvdata(dev));
> +
> +	mutex_lock(&info->mutex);
> +
> +	/* clkin = 6MHz */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL0,
> +		     SUNXI_GPADC_TP_CTRL0_ADC_CLK_DIVIDER(2) |
> +		     SUNXI_GPADC_TP_CTRL0_FS_DIV(7) |
> +		     SUNXI_GPADC_TP_CTRL0_T_ACQ(63));
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL1,
> +		     info->soc_specific->tp_mode_en);
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_CTRL3,
> +		     SUNXI_GPADC_TP_CTRL3_FILTER_EN |
> +		     SUNXI_GPADC_TP_CTRL3_FILTER_TYPE(1));
> +	/* period = SUNXI_GPADC_TP_TPR_TEMP_PERIOD * 256 * 16 / clkin; ~1.3s */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_TPR,
> +		     SUNXI_GPADC_TP_TPR_TEMP_ENABLE |
> +		     SUNXI_GPADC_TP_TPR_TEMP_PERIOD(1953));
> +
> +	mutex_unlock(&info->mutex);
> +
> +	return 0;
> +}
> +
> +static int sunxi_gpadc_get_temp(void *data, int *temp)
> +{
> +	struct sunxi_gpadc_dev *info = (struct sunxi_gpadc_dev *)data;
> +	int val, scale, offset;
> +
> +	/* If reading temperature times out, take stored previous value. */
> +	if (sunxi_gpadc_temp_read(info->indio_dev, &val))
> +		val = info->temp_data;
> +	sunxi_gpadc_temp_scale(info->indio_dev, &scale);
> +	sunxi_gpadc_temp_offset(info->indio_dev, &offset);
> +
> +	*temp = (val + offset) * scale;
> +
> +	return 0;
> +}
> +
> +static const struct thermal_zone_of_device_ops sunxi_ts_tz_ops = {
> +	.get_temp = &sunxi_gpadc_get_temp,
> +};
> +
> +static const struct dev_pm_ops sunxi_gpadc_pm_ops = {
> +	.runtime_suspend = &sunxi_gpadc_runtime_suspend,
> +	.runtime_resume = &sunxi_gpadc_runtime_resume,
> +};
> +
> +static int sunxi_gpadc_probe(struct platform_device *pdev)
> +{
> +	struct sunxi_gpadc_dev *info;
> +	struct iio_dev *indio_dev;
> +	int ret, irq;
> +	struct sunxi_gpadc_mfd_dev *sunxi_gpadc_mfd_dev;
> +	struct thermal_zone_device *tzd;
> +
> +	sunxi_gpadc_mfd_dev = dev_get_drvdata(pdev->dev.parent);
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	info = iio_priv(indio_dev);
> +
> +	mutex_init(&info->mutex);
> +	info->regmap = sunxi_gpadc_mfd_dev->regmap;
> +	info->indio_dev = indio_dev;
> +	atomic_set(&info->ignore_fifo_data_irq, 1);
> +	atomic_set(&info->ignore_temp_data_irq, 1);
> +	init_completion(&info->completion);
> +	indio_dev->name = dev_name(&pdev->dev);
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->dev.of_node = pdev->dev.of_node;
> +	indio_dev->info = &sunxi_gpadc_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->num_channels = ARRAY_SIZE(sunxi_gpadc_channels);
> +	indio_dev->channels = sunxi_gpadc_channels;
> +
> +	info->soc_specific = (struct sunxi_gpadc_soc_specific *)platform_get_device_id(pdev)->driver_data;
> +
> +	tzd = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, info,
> +						   &sunxi_ts_tz_ops);
> +	if (IS_ERR(tzd)) {
> +		dev_err(&pdev->dev, "could not register thermal sensor: %ld\n",
> +			PTR_ERR(tzd));
> +		return PTR_ERR(tzd);
> +	}
> +
> +	pm_runtime_set_autosuspend_delay(&pdev->dev,
> +					 SUNXI_GPADC_AUTOSUSPEND_DELAY);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +	pm_runtime_set_suspended(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +
> +	irq = platform_get_irq_byname(pdev, "TEMP_DATA_PENDING");
> +	if (irq < 0) {
> +		dev_err(&pdev->dev,
> +			"no TEMP_DATA_PENDING interrupt registered\n");
> +		ret = irq;
> +		goto err;
> +	}
> +
> +	irq = regmap_irq_get_virq(sunxi_gpadc_mfd_dev->regmap_irqc, irq);
> +	ret = devm_request_any_context_irq(&pdev->dev, irq,
> +					   sunxi_gpadc_temp_data_irq_handler, 0,
> +					   "temp_data", info);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev,
> +			"could not request TEMP_DATA_PENDING interrupt: %d\n",
> +			ret);
> +		goto err;
> +	}
> +
> +	disable_irq(irq);
> +	info->temp_data_irq = irq;
> +	atomic_set(&info->ignore_temp_data_irq, 0);
> +
> +	irq = platform_get_irq_byname(pdev, "FIFO_DATA_PENDING");
> +	if (irq < 0) {
> +		dev_err(&pdev->dev,
> +			"no FIFO_DATA_PENDING interrupt registered\n");
> +		ret = irq;
> +		goto err;
> +	}
> +
> +	irq = regmap_irq_get_virq(sunxi_gpadc_mfd_dev->regmap_irqc, irq);
> +	ret = devm_request_any_context_irq(&pdev->dev, irq,
> +					   sunxi_gpadc_fifo_data_irq_handler, 0,
> +					   "fifo_data", info);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev,
> +			"could not request FIFO_DATA_PENDING interrupt: %d\n",
> +			ret);
> +		goto err;
> +	}
> +
> +	disable_irq(irq);
> +	info->fifo_data_irq = irq;
> +	atomic_set(&info->ignore_fifo_data_irq, 0);
> +
> +	ret = iio_map_array_register(indio_dev, sunxi_gpadc_hwmon_maps);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to register iio map array\n");
> +		goto err;
> +	}
> +
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "could not register the device\n");
> +		goto err_map;
> +	}
> +
> +	return 0;
> +
> +err_map:
> +	iio_map_array_unregister(indio_dev);
> +
> +err:
> +	pm_runtime_put(&pdev->dev);
> +	/* Disable all hardware interrupts */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_INT_FIFOC, 0);
> +
> +	return ret;
> +}
> +
> +static int sunxi_gpadc_remove(struct platform_device *pdev)
> +{
> +	struct sunxi_gpadc_dev *info;
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> +	info = iio_priv(indio_dev);
> +	iio_device_unregister(indio_dev);
> +	iio_map_array_unregister(indio_dev);
> +	pm_runtime_put(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +	/* Disable all hardware interrupts */
> +	regmap_write(info->regmap, SUNXI_GPADC_TP_INT_FIFOC, 0);
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id sunxi_gpadc_id[] = {
> +	{ "sun4i-a10-gpadc-iio", (kernel_ulong_t)&sun4i_gpadc_soc_specific },
> +	{ "sun5i-a13-gpadc-iio", (kernel_ulong_t)&sun5i_gpadc_soc_specific },
> +	{ "sun6i-a31-gpadc-iio", (kernel_ulong_t)&sun6i_gpadc_soc_specific },
> +	{ /* sentinel */ },
> +};
> +
> +static struct platform_driver sunxi_gpadc_driver = {
> +	.driver = {
> +		.name = "sunxi-gpadc-iio",
> +		.pm = &sunxi_gpadc_pm_ops,
> +	},
> +	.id_table = sunxi_gpadc_id,
> +	.probe = sunxi_gpadc_probe,
> +	.remove = sunxi_gpadc_remove,
> +};
> +
> +module_platform_driver(sunxi_gpadc_driver);
> +
> +MODULE_DESCRIPTION("ADC driver for sunxi platforms");
> +MODULE_AUTHOR("Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
>