Date:   Sat, 14 Jan 2017 20:19:58 +0100
From:   Quentin Schulz <quentin.schulz@...e-electrons.com>
To:     Jonathan Cameron <jic23@...nel.org>, linux@...linux.org.uk,
        maxime.ripard@...e-electrons.com, wens@...e.org, knaack.h@....de,
        lars@...afoo.de, pmeerw@...erw.net, lee.jones@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-iio@...r.kernel.org, antoine.tenart@...e-electrons.com,
        thomas.petazzoni@...e-electrons.com,
        Zhang Rui <rui.zhang@...el.com>,
        "edubezval@...il.com" <edubezval@...il.com>
Subject: Re: [PATCH v9 3/3] iio: adc: add support for Allwinner SoCs ADC

Hi Jonathan,

On 08/01/2017 12:17, Jonathan Cameron wrote:
> On 30/12/16 14:40, Jonathan Cameron wrote:
>> On 13/12/16 14:33, 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.
>>>
>>> The thermal sensor requires the IP to be in touchscreen mode to return
>>> correct values. Therefore, if the user is continuously reading the ADC
>>> channel(s), the thermal framework in which the thermal sensor is
>>> registered will switch the IP in touchscreen mode to get a temperature
>>> value and requires a delay of 100ms (because of the mode switching),
>>> then the ADC will switch back to ADC mode and requires also a delay of
>>> 100ms. If the ADC readings are critical to user and the SoC temperature
>>> is not, this driver is capable of not registering the thermal sensor in
>>> the thermal framework and thus, "quicken" the ADC readings.
>>>
>>> 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@...e-electrons.com>
>>> Acked-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
>>> Acked-by: Jonathan Cameron <jic23@...nel.org>
>>> Acked-for-MFD-by: Lee Jones <lee.jones@...aro.org>
>> One comment inline but not a blocker.
>>
>> I would ideally like an ack from the thermal side.  The relevant code
>> is small, but best to be sure and keep them in the loop as well.
>>
>> It does feel a little convoluted to have both this directly providing
>> a thermal zone and being able to create one indirectly through hwmon as
>> well but this solution works for me I think...
>>
>> Cc'd Zang and Eduardo.
> Nothing seems to have come through on that front.
> 
> I need to get a pull request out to Greg and rebase my tree before I have
> the precursor patch in place. Give me a bump if you haven't heard anything by
> the time next week.
> 

Kindly "giving you a bump" you as requested since I haven't heard from
you for a week.

Thanks,
Quentin

> Thanks,
> 
> Jonathan
>>
>> Jonathan
>>> ---
>>>
>>> v9:
>>>  - clarify comment on why we have to use the parent node as node for
>>>  registering in thermal framework, (backward compatibility)
>>>  - clarify comment on why we can disable CONFIG_THERMAL_OF,
>>>  - clarify Kconfig help to say that CONFIG_THERMAL_OF can be disabled
>>>  but should not in most cases,
>>>  - make return value of devm_thermal_zone_of_sensor_register a local
>>>  variable of the condition block,
>>>  - correct scale from _PLUS_MICRO to _PLUS_NANO for ADC raw readings
>>>  scale,
>>>
>>> v8:
>>>  - remove Kconfig depends on !TOUCHSCREEN_SUN4I (moved to
>>> MFD_SUN4I_GPADC),
>>>  - fix return values of regmap_irq_get_virq and platform_get_irq_byname
>>> stored in an unsigned int and then check if negative,
>>>  - fix uninitialized ret value when an error occurs while registering
>>> the thermal sensor in the framework,
>>>
>>> v7:
>>>  - add Kconfig depends on !TOUCHSCREEN_SUN4I,
>>>  - remove Kconfig selects THERMAL_OF,
>>>  - do not register thermal sensor if CONFIG_THERMAL_OF is disabled,
>>>  - disable irq in irq_handler rather than in read_raw,
>>>  - add delay when switching the IP's mode or channel (delay empirically found),
>>>  - quicken thermal sensor interrupt period,
>>>  - add masks for channel bits,
>>>  - fix deadlock in sun4i_gpadc_read if regmap_read/write fails,
>>>  - move some logic from sun4i_gpadc_read to sun4i_prepare_for_irq,
>>>  - mark last busy for runtime_pm only on success in sun4i_gpadc_read,
>>>  - remove cached values,
>>>  - increase wait_for_completion_timeout timeout to 1s to be sure to not miss the
>>>  thermal interrupt,
>>>  - add voltage scale,
>>>  - use devm_iio_device_register,
>>>
>>> v6:
>>>  - remove "-mfd" from filenames and variables inside MFD driver,
>>>  - use DEFINE_RES_IRQ_NAMED instead of setting resources manually,
>>>  - cosmetic changes,
>>>  - use IDs and switch over ID to get cells specific to an architecture, instead
>>>  of using cells direclty, in of_device_id.data,
>>>  - compute size of mfd_cells array instead of hardcoded one,
>>>
>>> v5:
>>>  - correct mail address,
>>>
>>> v4:
>>>  - rename files and variables from sunxi* to sun4i*,
>>>  - rename defines from SUNXI_* to SUN4I_* or SUN6I_*,
>>>  - remove TP in defines name,
>>>  - rename SUNXI_IRQ_* to SUN4I_GPADC_IRQ_* for consistency,
>>>  - use devm functions for regmap_add_irq_chip and mfd_add_devices,
>>>  - remove remove functions (now empty thanks to devm functions),
>>>
>>> v3:
>>>  - use defines in regmap_irq instead of hard coded BITs,
>>>  - use of_device_id data field to chose which MFD cells to add considering
>>>    the compatible responsible of the MFD probe,
>>>  - remove useless initializations,
>>>  - disable all interrupts before adding them to regmap_irqchip,
>>>  - add goto error label in probe,
>>>  - correct wrapping in header license,
>>>  - move defines from IIO driver to header,
>>>  - use GENMASK to limit the size of the variable passed to a macro,
>>>  - prefix register BIT defines with the name of the register,
>>>  - reorder defines,
>>>
>>> v2:
>>>  - add license headers,
>>>  - reorder alphabetically includes,
>>>  - add SUNXI_GPADC_ prefixes for defines,
>>>
>>>  drivers/iio/adc/Kconfig           |  17 ++
>>>  drivers/iio/adc/Makefile          |   1 +
>>>  drivers/iio/adc/sun4i-gpadc-iio.c | 613 ++++++++++++++++++++++++++++++++++++++
>>>  include/linux/mfd/sun4i-gpadc.h   |   2 +
>>>  4 files changed, 633 insertions(+)
>>>  create mode 100644 drivers/iio/adc/sun4i-gpadc-iio.c
>>>
>>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>>> index 99c0514..6a6d369 100644
>>> --- a/drivers/iio/adc/Kconfig
>>> +++ b/drivers/iio/adc/Kconfig
>>> @@ -434,6 +434,23 @@ config STX104
>>>  	  The base port addresses for the devices may be configured via the base
>>>  	  array module parameter.
>>>  
>>> +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.
>>> +
>>> +	  The thermal sensor slows down ADC readings and can be disabled by
>>> +	  disabling CONFIG_THERMAL_OF. However, the thermal sensor should be
>>> +	  enabled by default since the SoC temperature is usually more critical
>>> +	  than ADC readings.
>>> +
>>> +	  To compile this driver as a module, choose M here: the module will be
>>> +	  called sun4i-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 7a40c04..18ce8d6 100644
>>> --- a/drivers/iio/adc/Makefile
>>> +++ b/drivers/iio/adc/Makefile
>>> @@ -41,6 +41,7 @@ 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_STX104) += stx104.o
>>> +obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
>>>  obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>>>  obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>>>  obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
>>> diff --git a/drivers/iio/adc/sun4i-gpadc-iio.c b/drivers/iio/adc/sun4i-gpadc-iio.c
>>> new file mode 100644
>>> index 0000000..a8e134f
>>> --- /dev/null
>>> +++ b/drivers/iio/adc/sun4i-gpadc-iio.c
>>> @@ -0,0 +1,613 @@
>>> +/* ADC driver for sunxi platforms' (A10, A13 and A31) GPADC
>>> + *
>>> + * Copyright (c) 2016 Quentin Schulz <quentin.schulz@...e-electrons.com>
>>> + *
>>> + * 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 resets 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 was 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/delay.h>
>>> +
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/driver.h>
>>> +#include <linux/iio/machine.h>
>>> +#include <linux/mfd/sun4i-gpadc.h>
>>> +
>>> +static unsigned int sun4i_gpadc_chan_select(unsigned int chan)
>>> +{
>>> +	return SUN4I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
>>> +}
>>> +
>>> +static unsigned int sun6i_gpadc_chan_select(unsigned int chan)
>>> +{
>>> +	return SUN6I_GPADC_CTRL1_ADC_CHAN_SELECT(chan);
>>> +}
>>> +
>>> +struct gpadc_data {
>>> +	int		temp_offset;
>>> +	int		temp_scale;
>>> +	unsigned int	tp_mode_en;
>>> +	unsigned int	tp_adc_select;
>>> +	unsigned int	(*adc_chan_select)(unsigned int chan);
>>> +	unsigned int	adc_chan_mask;
>>> +};
>>> +
>>> +static const struct gpadc_data sun4i_gpadc_data = {
>>> +	.temp_offset = -1932,
>>> +	.temp_scale = 133,
>>> +	.tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
>>> +	.tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
>>> +	.adc_chan_select = &sun4i_gpadc_chan_select,
>>> +	.adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
>>> +};
>>> +
>>> +static const struct gpadc_data sun5i_gpadc_data = {
>>> +	.temp_offset = -1447,
>>> +	.temp_scale = 100,
>>> +	.tp_mode_en = SUN4I_GPADC_CTRL1_TP_MODE_EN,
>>> +	.tp_adc_select = SUN4I_GPADC_CTRL1_TP_ADC_SELECT,
>>> +	.adc_chan_select = &sun4i_gpadc_chan_select,
>>> +	.adc_chan_mask = SUN4I_GPADC_CTRL1_ADC_CHAN_MASK,
>>> +};
>>> +
>>> +static const struct gpadc_data sun6i_gpadc_data = {
>>> +	.temp_offset = -1623,
>>> +	.temp_scale = 167,
>>> +	.tp_mode_en = SUN6I_GPADC_CTRL1_TP_MODE_EN,
>>> +	.tp_adc_select = SUN6I_GPADC_CTRL1_TP_ADC_SELECT,
>>> +	.adc_chan_select = &sun6i_gpadc_chan_select,
>>> +	.adc_chan_mask = SUN6I_GPADC_CTRL1_ADC_CHAN_MASK,
>>> +};
>>> +
>>> +struct sun4i_gpadc_iio {
>>> +	struct iio_dev			*indio_dev;
>>> +	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 gpadc_data		*data;
>>> +	/* prevents concurrent reads of temperature and ADC */
>>> +	struct mutex			mutex;
>>> +};
>>> +
>>> +#define SUN4I_GPADC_ADC_CHANNEL(_channel, _name) {		\
>>> +	.type = IIO_VOLTAGE,					\
>>> +	.indexed = 1,						\
>>> +	.channel = _channel,					\
>>> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
>>> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
>>> +	.datasheet_name = _name,				\
>>> +}
>>> +
>>> +static struct iio_map sun4i_gpadc_hwmon_maps[] = {
>>> +	{
>>> +		.adc_channel_label = "temp_adc",
>>> +		.consumer_dev_name = "iio_hwmon.0",
>> It's theoretically possible we have another one of these which will make
>> life interesting.  Oh well, no easy way around that at the mo...
>>> +	},
>>> +	{ /* sentinel */ },
>>> +};
>>> +
>>> +static const struct iio_chan_spec sun4i_gpadc_channels[] = {
>>> +	SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
>>> +	SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
>>> +	SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
>>> +	SUN4I_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 const struct iio_chan_spec sun4i_gpadc_channels_no_temp[] = {
>>> +	SUN4I_GPADC_ADC_CHANNEL(0, "adc_chan0"),
>>> +	SUN4I_GPADC_ADC_CHANNEL(1, "adc_chan1"),
>>> +	SUN4I_GPADC_ADC_CHANNEL(2, "adc_chan2"),
>>> +	SUN4I_GPADC_ADC_CHANNEL(3, "adc_chan3"),
>>> +};
>>> +
>>> +static int sun4i_prepare_for_irq(struct iio_dev *indio_dev, int channel,
>>> +				 unsigned int irq)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +	int ret;
>>> +	u32 reg;
>>> +
>>> +	pm_runtime_get_sync(indio_dev->dev.parent);
>>> +
>>> +	reinit_completion(&info->completion);
>>> +
>>> +	ret = regmap_write(info->regmap, SUN4I_GPADC_INT_FIFOC,
>>> +			   SUN4I_GPADC_INT_FIFOC_TP_FIFO_TRIG_LEVEL(1) |
>>> +			   SUN4I_GPADC_INT_FIFOC_TP_FIFO_FLUSH);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = regmap_read(info->regmap, SUN4I_GPADC_CTRL1, &reg);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	if (irq == info->fifo_data_irq) {
>>> +		ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
>>> +				   info->data->tp_mode_en |
>>> +				   info->data->tp_adc_select |
>>> +				   info->data->adc_chan_select(channel));
>>> +		/*
>>> +		 * When the IP changes channel, it needs a bit of time to get
>>> +		 * correct values.
>>> +		 */
>>> +		if ((reg & info->data->adc_chan_mask) !=
>>> +			 info->data->adc_chan_select(channel))
>>> +			mdelay(10);
>>> +
>>> +	} else {
>>> +		/*
>>> +		 * The temperature sensor returns valid data only when the ADC
>>> +		 * operates in touchscreen mode.
>>> +		 */
>>> +		ret = regmap_write(info->regmap, SUN4I_GPADC_CTRL1,
>>> +				   info->data->tp_mode_en);
>>> +	}
>>> +
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	/*
>>> +	 * When the IP changes mode between ADC or touchscreen, it
>>> +	 * needs a bit of time to get correct values.
>>> +	 */
>>> +	if ((reg & info->data->tp_adc_select) != info->data->tp_adc_select)
>>> +		mdelay(100);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_gpadc_read(struct iio_dev *indio_dev, int channel, int *val,
>>> +			    unsigned int irq)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +	int ret;
>>> +
>>> +	mutex_lock(&info->mutex);
>>> +
>>> +	ret = sun4i_prepare_for_irq(indio_dev, channel, irq);
>>> +	if (ret)
>>> +		goto err;
>>> +
>>> +	enable_irq(irq);
>>> +
>>> +	/*
>>> +	 * The temperature sensor throws an interruption periodically (currently
>>> +	 * set at periods of ~0.6s in sun4i_gpadc_runtime_resume). A 1s delay
>>> +	 * makes sure an interruption occurs in normal conditions. If it doesn't
>>> +	 * occur, then there is a timeout.
>>> +	 */
>>> +	if (!wait_for_completion_timeout(&info->completion,
>>> +					 msecs_to_jiffies(1000))) {
>>> +		ret = -ETIMEDOUT;
>>> +		goto err;
>>> +	}
>>> +
>>> +	if (irq == info->fifo_data_irq)
>>> +		*val = info->adc_data;
>>> +	else
>>> +		*val = info->temp_data;
>>> +
>>> +	ret = 0;
>>> +	pm_runtime_mark_last_busy(indio_dev->dev.parent);
>>> +
>>> +err:
>>> +	pm_runtime_put_autosuspend(indio_dev->dev.parent);
>>> +	mutex_unlock(&info->mutex);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static int sun4i_gpadc_adc_read(struct iio_dev *indio_dev, int channel,
>>> +				int *val)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +
>>> +	return sun4i_gpadc_read(indio_dev, channel, val, info->fifo_data_irq);
>>> +}
>>> +
>>> +static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int *val)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +
>>> +	return sun4i_gpadc_read(indio_dev, 0, val, info->temp_data_irq);
>>> +}
>>> +
>>> +static int sun4i_gpadc_temp_offset(struct iio_dev *indio_dev, int *val)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +
>>> +	*val = info->data->temp_offset;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_gpadc_temp_scale(struct iio_dev *indio_dev, int *val)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
>>> +
>>> +	*val = info->data->temp_scale;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_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 = sun4i_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 = sun4i_gpadc_adc_read(indio_dev, chan->channel,
>>> +						   val);
>>> +		else
>>> +			ret = sun4i_gpadc_temp_read(indio_dev, val);
>>> +
>>> +		if (ret)
>>> +			return ret;
>>> +
>>> +		return IIO_VAL_INT;
>>> +	case IIO_CHAN_INFO_SCALE:
>>> +		if (chan->type == IIO_VOLTAGE) {
>>> +			/* 3000mV / 4096 * raw */
>>> +			*val = 0;
>>> +			*val2 = 732421875;
>>> +			return IIO_VAL_INT_PLUS_NANO;
>>> +		}
>>> +
>>> +		ret = sun4i_gpadc_temp_scale(indio_dev, val);
>>> +		if (ret)
>>> +			return ret;
>>> +
>>> +		return IIO_VAL_INT;
>>> +	default:
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	return -EINVAL;
>>> +}
>>> +
>>> +static const struct iio_info sun4i_gpadc_iio_info = {
>>> +	.read_raw = sun4i_gpadc_read_raw,
>>> +	.driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +static irqreturn_t sun4i_gpadc_temp_data_irq_handler(int irq, void *dev_id)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = dev_id;
>>> +
>>> +	if (atomic_read(&info->ignore_temp_data_irq))
>>> +		goto out;
>>> +
>>> +	if (!regmap_read(info->regmap, SUN4I_GPADC_TEMP_DATA, &info->temp_data))
>>> +		complete(&info->completion);
>>> +
>>> +out:
>>> +	disable_irq_nosync(info->temp_data_irq);
>>> +	return IRQ_HANDLED;
>>> +}
>>> +
>>> +static irqreturn_t sun4i_gpadc_fifo_data_irq_handler(int irq, void *dev_id)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = dev_id;
>>> +
>>> +	if (atomic_read(&info->ignore_fifo_data_irq))
>>> +		goto out;
>>> +
>>> +	if (!regmap_read(info->regmap, SUN4I_GPADC_DATA, &info->adc_data))
>>> +		complete(&info->completion);
>>> +
>>> +out:
>>> +	disable_irq_nosync(info->fifo_data_irq);
>>> +	return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int sun4i_gpadc_runtime_suspend(struct device *dev)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>>> +
>>> +	/* Disable the ADC on IP */
>>> +	regmap_write(info->regmap, SUN4I_GPADC_CTRL1, 0);
>>> +	/* Disable temperature sensor on IP */
>>> +	regmap_write(info->regmap, SUN4I_GPADC_TPR, 0);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_gpadc_runtime_resume(struct device *dev)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(dev));
>>> +
>>> +	/* clkin = 6MHz */
>>> +	regmap_write(info->regmap, SUN4I_GPADC_CTRL0,
>>> +		     SUN4I_GPADC_CTRL0_ADC_CLK_DIVIDER(2) |
>>> +		     SUN4I_GPADC_CTRL0_FS_DIV(7) |
>>> +		     SUN4I_GPADC_CTRL0_T_ACQ(63));
>>> +	regmap_write(info->regmap, SUN4I_GPADC_CTRL1, info->data->tp_mode_en);
>>> +	regmap_write(info->regmap, SUN4I_GPADC_CTRL3,
>>> +		     SUN4I_GPADC_CTRL3_FILTER_EN |
>>> +		     SUN4I_GPADC_CTRL3_FILTER_TYPE(1));
>>> +	/* period = SUN4I_GPADC_TPR_TEMP_PERIOD * 256 * 16 / clkin; ~0.6s */
>>> +	regmap_write(info->regmap, SUN4I_GPADC_TPR,
>>> +		     SUN4I_GPADC_TPR_TEMP_ENABLE |
>>> +		     SUN4I_GPADC_TPR_TEMP_PERIOD(800));
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_gpadc_get_temp(void *data, int *temp)
>>> +{
>>> +	struct sun4i_gpadc_iio *info = (struct sun4i_gpadc_iio *)data;
>>> +	int val, scale, offset;
>>> +
>>> +	if (sun4i_gpadc_temp_read(info->indio_dev, &val))
>>> +		return -ETIMEDOUT;
>>> +
>>> +	sun4i_gpadc_temp_scale(info->indio_dev, &scale);
>>> +	sun4i_gpadc_temp_offset(info->indio_dev, &offset);
>>> +
>>> +	*temp = (val + offset) * scale;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static const struct thermal_zone_of_device_ops sun4i_ts_tz_ops = {
>>> +	.get_temp = &sun4i_gpadc_get_temp,
>>> +};
>>> +
>>> +static const struct dev_pm_ops sun4i_gpadc_pm_ops = {
>>> +	.runtime_suspend = &sun4i_gpadc_runtime_suspend,
>>> +	.runtime_resume = &sun4i_gpadc_runtime_resume,
>>> +};
>>> +
>>> +static int sun4i_irq_init(struct platform_device *pdev, const char *name,
>>> +			  irq_handler_t handler, const char *devname,
>>> +			  unsigned int *irq, atomic_t *atomic)
>>> +{
>>> +	int ret;
>>> +	struct sun4i_gpadc_dev *mfd_dev = dev_get_drvdata(pdev->dev.parent);
>>> +	struct sun4i_gpadc_iio *info = iio_priv(dev_get_drvdata(&pdev->dev));
>>> +
>>> +	/*
>>> +	 * Once the interrupt is activated, the IP continuously performs
>>> +	 * conversions thus throws interrupts. The interrupt is activated right
>>> +	 * after being requested but we want to control when these interrupts
>>> +	 * occur thus we disable it right after being requested. However, an
>>> +	 * interrupt might occur between these two instructions and we have to
>>> +	 * make sure that does not happen, by using atomic flags. We set the
>>> +	 * flag before requesting the interrupt and unset it right after
>>> +	 * disabling the interrupt. When an interrupt occurs between these two
>>> +	 * instructions, reading the atomic flag will tell us to ignore the
>>> +	 * interrupt.
>>> +	 */
>>> +	atomic_set(atomic, 1);
>>> +
>>> +	ret = platform_get_irq_byname(pdev, name);
>>> +	if (ret < 0) {
>>> +		dev_err(&pdev->dev, "no %s interrupt registered\n", name);
>>> +		return ret;
>>> +	}
>>> +
>>> +	ret = regmap_irq_get_virq(mfd_dev->regmap_irqc, ret);
>>> +	if (ret < 0) {
>>> +		dev_err(&pdev->dev, "failed to get virq for irq %s\n", name);
>>> +		return ret;
>>> +	}
>>> +
>>> +	*irq = ret;
>>> +	ret = devm_request_any_context_irq(&pdev->dev, *irq, handler, 0,
>>> +					   devname, info);
>>> +	if (ret < 0) {
>>> +		dev_err(&pdev->dev, "could not request %s interrupt: %d\n",
>>> +			name, ret);
>>> +		return ret;
>>> +	}
>>> +
>>> +	disable_irq(*irq);
>>> +	atomic_set(atomic, 0);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int sun4i_gpadc_probe(struct platform_device *pdev)
>>> +{
>>> +	struct sun4i_gpadc_iio *info;
>>> +	struct iio_dev *indio_dev;
>>> +	int ret;
>>> +	struct sun4i_gpadc_dev *sun4i_gpadc_dev;
>>> +
>>> +	sun4i_gpadc_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);
>>> +	platform_set_drvdata(pdev, indio_dev);
>>> +
>>> +	mutex_init(&info->mutex);
>>> +	info->regmap = sun4i_gpadc_dev->regmap;
>>> +	info->indio_dev = indio_dev;
>>> +	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 = &sun4i_gpadc_iio_info;
>>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>>> +	indio_dev->num_channels = ARRAY_SIZE(sun4i_gpadc_channels);
>>> +	indio_dev->channels = sun4i_gpadc_channels;
>>> +
>>> +	info->data = (struct gpadc_data *)platform_get_device_id(pdev)->driver_data;
>>> +
>>> +	/*
>>> +	 * Since the controller needs to be in touchscreen mode for its thermal
>>> +	 * sensor to operate properly, and that switching between the two modes
>>> +	 * needs a delay, always registering in the thermal framework will
>>> +	 * significantly slow down the conversion rate of the ADCs.
>>> +	 *
>>> +	 * Therefore, instead of depending on THERMAL_OF in Kconfig, we only
>>> +	 * register the sensor if that option is enabled, eventually leaving
>>> +	 * that choice to the user.
>>> +	 */
>>> +
>>> +	if (IS_ENABLED(CONFIG_THERMAL_OF)) {
>>> +		/*
>>> +		 * This driver is a child of an MFD which has a node in the DT
>>> +		 * but not its children, because of DT backward compatibility
>>> +		 * for A10, A13 and A31 SoCs. Therefore, the resulting devices
>>> +		 * of this driver do not have an of_node variable.
>>> +		 * However, its parent (the MFD driver) has an of_node variable
>>> +		 * and since devm_thermal_zone_of_sensor_register uses its first
>>> +		 * argument to match the phandle defined in the node of the
>>> +		 * thermal driver with the of_node of the device passed as first
>>> +		 * argument and the third argument to call ops from
>>> +		 * thermal_zone_of_device_ops, the solution is to use the parent
>>> +		 * device as first argument to match the phandle with its
>>> +		 * of_node, and the device from this driver as third argument to
>>> +		 * return the temperature.
>>> +		 */
>>> +		struct thermal_zone_device *tzd;
>>> +		tzd = devm_thermal_zone_of_sensor_register(pdev->dev.parent, 0,
>>> +							   info,
>>> +							   &sun4i_ts_tz_ops);
>>> +		if (IS_ERR(tzd)) {
>>> +			dev_err(&pdev->dev,
>>> +				"could not register thermal sensor: %ld\n",
>>> +				PTR_ERR(tzd));
>>> +			ret = PTR_ERR(tzd);
>>> +			goto err;
>>> +		}
>>> +	} else {
>>> +		indio_dev->num_channels =
>>> +			ARRAY_SIZE(sun4i_gpadc_channels_no_temp);
>>> +		indio_dev->channels = sun4i_gpadc_channels_no_temp;
>>> +	}
>>> +
>>> +	pm_runtime_set_autosuspend_delay(&pdev->dev,
>>> +					 SUN4I_GPADC_AUTOSUSPEND_DELAY);
>>> +	pm_runtime_use_autosuspend(&pdev->dev);
>>> +	pm_runtime_set_suspended(&pdev->dev);
>>> +	pm_runtime_enable(&pdev->dev);
>>> +
>>> +	if (IS_ENABLED(CONFIG_THERMAL_OF)) {
>>> +		ret = sun4i_irq_init(pdev, "TEMP_DATA_PENDING",
>>> +				     sun4i_gpadc_temp_data_irq_handler,
>>> +				     "temp_data", &info->temp_data_irq,
>>> +				     &info->ignore_temp_data_irq);
>>> +		if (ret < 0)
>>> +			goto err;
>>> +	}
>>> +
>>> +	ret = sun4i_irq_init(pdev, "FIFO_DATA_PENDING",
>>> +			     sun4i_gpadc_fifo_data_irq_handler, "fifo_data",
>>> +			     &info->fifo_data_irq, &info->ignore_fifo_data_irq);
>>> +	if (ret < 0)
>>> +		goto err;
>>> +
>>> +	if (IS_ENABLED(CONFIG_THERMAL_OF)) {
>>> +		ret = iio_map_array_register(indio_dev, sun4i_gpadc_hwmon_maps);
>>> +		if (ret < 0) {
>>> +			dev_err(&pdev->dev,
>>> +				"failed to register iio map array\n");
>>> +			goto err;
>>> +		}
>>> +	}
>>> +
>>> +	ret = devm_iio_device_register(&pdev->dev, indio_dev);
>>> +	if (ret < 0) {
>>> +		dev_err(&pdev->dev, "could not register the device\n");
>>> +		goto err_map;
>>> +	}
>>> +
>>> +	return 0;
>>> +
>>> +err_map:
>>> +	if (IS_ENABLED(CONFIG_THERMAL_OF))
>>> +		iio_map_array_unregister(indio_dev);
>>> +
>>> +err:
>>> +	pm_runtime_put(&pdev->dev);
>>> +	pm_runtime_disable(&pdev->dev);
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static int sun4i_gpadc_remove(struct platform_device *pdev)
>>> +{
>>> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>>> +
>>> +	pm_runtime_put(&pdev->dev);
>>> +	pm_runtime_disable(&pdev->dev);
>>> +	if (IS_ENABLED(CONFIG_THERMAL_OF))
>>> +		iio_map_array_unregister(indio_dev);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static const struct platform_device_id sun4i_gpadc_id[] = {
>>> +	{ "sun4i-a10-gpadc-iio", (kernel_ulong_t)&sun4i_gpadc_data },
>>> +	{ "sun5i-a13-gpadc-iio", (kernel_ulong_t)&sun5i_gpadc_data },
>>> +	{ "sun6i-a31-gpadc-iio", (kernel_ulong_t)&sun6i_gpadc_data },
>>> +	{ /* sentinel */ },
>>> +};
>>> +
>>> +static struct platform_driver sun4i_gpadc_driver = {
>>> +	.driver = {
>>> +		.name = "sun4i-gpadc-iio",
>>> +		.pm = &sun4i_gpadc_pm_ops,
>>> +	},
>>> +	.id_table = sun4i_gpadc_id,
>>> +	.probe = sun4i_gpadc_probe,
>>> +	.remove = sun4i_gpadc_remove,
>>> +};
>>> +
>>> +module_platform_driver(sun4i_gpadc_driver);
>>> +
>>> +MODULE_DESCRIPTION("ADC driver for sunxi platforms");
>>> +MODULE_AUTHOR("Quentin Schulz <quentin.schulz@...e-electrons.com>");
>>> +MODULE_LICENSE("GPL v2");
>>> diff --git a/include/linux/mfd/sun4i-gpadc.h b/include/linux/mfd/sun4i-gpadc.h
>>> index d7a29f2..509e736 100644
>>> --- a/include/linux/mfd/sun4i-gpadc.h
>>> +++ b/include/linux/mfd/sun4i-gpadc.h
>>> @@ -28,6 +28,7 @@
>>>  #define SUN4I_GPADC_CTRL1_TP_MODE_EN			BIT(4)
>>>  #define SUN4I_GPADC_CTRL1_TP_ADC_SELECT			BIT(3)
>>>  #define SUN4I_GPADC_CTRL1_ADC_CHAN_SELECT(x)		(GENMASK(2, 0) & (x))
>>> +#define SUN4I_GPADC_CTRL1_ADC_CHAN_MASK			GENMASK(2, 0)
>>>  
>>>  /* TP_CTRL1 bits for sun6i SOCs */
>>>  #define SUN6I_GPADC_CTRL1_TOUCH_PAN_CALI_EN		BIT(7)
>>> @@ -35,6 +36,7 @@
>>>  #define SUN6I_GPADC_CTRL1_TP_MODE_EN			BIT(5)
>>>  #define SUN6I_GPADC_CTRL1_TP_ADC_SELECT			BIT(4)
>>>  #define SUN6I_GPADC_CTRL1_ADC_CHAN_SELECT(x)		(GENMASK(3, 0) & BIT(x))
>>> +#define SUN6I_GPADC_CTRL1_ADC_CHAN_MASK			GENMASK(3, 0)
>>>  
>>>  #define SUN4I_GPADC_CTRL2				0x08
>>>  
>>>
>>
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> 

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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