[PATCH v9 3/3] iio: adc: add support for Allwinner SoCs ADC

From: jic23@kernel.org (Jonathan Cameron)
Date: 2017-02-06 18:35:07
Also in: linux-iio, lkml

On 06/02/17 07:37, Quentin Schulz wrote:

Hi Jonathan,

On 14/01/2017 20:28, Jonathan Cameron wrote:

quoted


On 14 January 2017 19:19:58 GMT+00:00, Quentin Schulz [off-list ref] wrote:

quoted

Hi Jonathan,

On 08/01/2017 12:17, Jonathan Cameron wrote:

quoted

On 30/12/16 14:40, Jonathan Cameron wrote:

quoted

On 13/12/16 14:33, Quentin Schulz wrote:

quoted

The Allwinner SoCs all have an ADC that can also act as a

touchscreen

quoted

controller and a thermal sensor. This patch adds the ADC driver

which is

quoted

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

quoted

the driver in the thermal framework.

The thermal sensor requires the IP to be in touchscreen mode to

return

quoted

correct values. Therefore, if the user is continuously reading the

ADC

quoted

channel(s), the thermal framework in which the thermal sensor is
registered will switch the IP in touchscreen mode to get a

temperature

quoted

value and requires a delay of 100ms (because of the mode

switching),

quoted

then the ADC will switch back to ADC mode and requires also a delay

of

quoted

100ms. If the ADC readings are critical to user and the SoC

temperature

quoted

is not, this driver is capable of not registering the thermal

sensor in

quoted

the thermal framework and thus, "quicken" the ADC readings.

This driver probes on three different platform_device_id to take

into

quoted

account slight differences (registers bit and temperature

computation)

quoted

between Allwinner SoCs ADCs.

Signed-off-by: Quentin Schulz <redacted>
Acked-by: Maxime Ripard <redacted>
Acked-by: Jonathan Cameron <jic23@kernel.org>
Acked-for-MFD-by: Lee Jones [off-list ref]

One comment inline but not a blocker.

I would ideally like an ack from the thermal side.  The relevant

code

quoted

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

quoted

a thermal zone and being able to create one indirectly through hwmon

as

quoted

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

quoted

the precursor patch in place. Give me a bump if you haven't heard

anything by

quoted

the time next week.

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

Greg hasn't pulled yet, so may be a few more days.

J

I haven't received any news from you on the merging of this patch series
for a month, so kindly pinging.

Gah!  Sorry, I completely lost this one in my patch queue. Thanks for the
reminder.

Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

I'm afraid due to my tardiness it's missed the coming merge window, but
I'll make sure it goes in my first pull request for the next cycle.

Jonathan

Thanks,
Quentin

quoted

Thanks,
Quentin

quoted

Thanks,

Jonathan

quoted

Jonathan

quoted

---

v9:
 - clarify comment on why we have to use the parent node as node

for

quoted

 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

quoted

 but should not in most cases,
 - make return value of devm_thermal_zone_of_sensor_register a

local

quoted

 variable of the condition block,
 - correct scale from _PLUS_MICRO to _PLUS_NANO for ADC raw

readings

quoted

 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

quoted

stored in an unsigned int and then check if negative,
 - fix uninitialized ret value when an error occurs while

registering

quoted

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),

quoted

 - 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,

quoted

 - remove cached values,
 - increase wait_for_completion_timeout timeout to 1s to be sure to

not miss the

quoted

 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

quoted

 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

quoted

   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

++++++++++++++++++++++++++++++++++++++

quoted

 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

quoted

 	  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

quoted

+	  GPADC. This ADC provides 4 channels which can be used as an ADC

or as

quoted

+	  a touchscreen input and one channel for thermal sensor.
+
+	  The thermal sensor slows down ADC readings and can be disabled

by

quoted

+	  disabling CONFIG_THERMAL_OF. However, the thermal sensor should

be

quoted

+	  enabled by default since the SoC temperature is usually more

critical

quoted

+	  than ADC readings.
+
+	  To compile this driver as a module, choose M here: the module

will be

quoted

+	  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

quoted

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

[off-list ref]

quoted

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

modify it under

quoted

+ * the terms of the GNU General Public License version 2 as

published by the

quoted

+ * Free Software Foundation.
+ *
+ * The Allwinner SoCs all have an ADC that can also act as a

touchscreen

quoted

+ * controller and a thermal sensor.
+ * The thermal sensor works only when the ADC acts as a

touchscreen controller

quoted

+ * and is configured to throw an interrupt every fixed periods of

time (let say

quoted

+ * every X seconds).
+ * One would be tempted to disable the IP on the hardware side

rather than

quoted

+ * disabling interrupts to save some power but that resets the

internal clock of

quoted

+ * the IP, resulting in having to wait X seconds every time we

want to read the

quoted

+ * value of the thermal sensor.
+ * This is also the reason of using autosuspend in pm_runtime. If

there was no

quoted

+ * autosuspend, the thermal sensor would need X seconds after

every

quoted

+ * pm_runtime_get_sync to get a value from the ADC. The

autosuspend allows the

quoted

+ * thermal sensor to be requested again in a certain time span

before it gets

quoted

+ * 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

quoted

life interesting.  Oh well, no easy way around that at the mo...

quoted

+	},
+	{ /* 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[] =

quoted

+	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,

quoted

+				 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)

quoted

+		mdelay(100);
+
+	return 0;
+}
+
+static int sun4i_gpadc_read(struct iio_dev *indio_dev, int

channel, int *val,

quoted

+			    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

quoted

+	 * set at periods of ~0.6s in sun4i_gpadc_runtime_resume). A 1s

delay

quoted

+	 * makes sure an interruption occurs in normal conditions. If it

doesn't

quoted

+	 * 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,

quoted

+				int *val)
+{
+	struct sun4i_gpadc_iio *info = iio_priv(indio_dev);
+
+	return sun4i_gpadc_read(indio_dev, channel, val,

info->fifo_data_irq);

quoted

+}
+
+static int sun4i_gpadc_temp_read(struct iio_dev *indio_dev, int

*val)

quoted

+{
+	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)

quoted

+{
+	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)

quoted

+{
+	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)

quoted

+{
+	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))

quoted

+		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)

quoted

+{
+	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))

quoted

+		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);

quoted

+	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

*/

quoted

+	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,

quoted

+			  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);

quoted

+	struct sun4i_gpadc_iio *info =

iio_priv(dev_get_drvdata(&pdev->dev));

quoted

+
+	/*
+	 * Once the interrupt is activated, the IP continuously performs
+	 * conversions thus throws interrupts. The interrupt is activated

right

quoted

+	 * after being requested but we want to control when these

interrupts

quoted

+	 * occur thus we disable it right after being requested. However,

an

quoted

+	 * interrupt might occur between these two instructions and we

have to

quoted

+	 * make sure that does not happen, by using atomic flags. We set

the

quoted

+	 * flag before requesting the interrupt and unset it right after
+	 * disabling the interrupt. When an interrupt occurs between

these two

quoted

+	 * instructions, reading the atomic flag will tell us to ignore

the

quoted

+	 * 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;

quoted

+
+	/*
+	 * Since the controller needs to be in touchscreen mode for its

thermal

quoted

+	 * sensor to operate properly, and that switching between the two

modes

quoted

+	 * needs a delay, always registering in the thermal framework

will

quoted

+	 * significantly slow down the conversion rate of the ADCs.
+	 *
+	 * Therefore, instead of depending on THERMAL_OF in Kconfig, we

only

quoted

+	 * register the sensor if that option is enabled, eventually

leaving

quoted

+	 * 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

[off-list ref]");

quoted

+MODULE_LICENSE("GPL v2");

diff --git a/include/linux/mfd/sun4i-gpadc.h

b/include/linux/mfd/sun4i-gpadc.h

quoted

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))

quoted

+#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))

quoted

+#define SUN6I_GPADC_CTRL1_ADC_CHAN_MASK			GENMASK(3, 0)
 
 #define SUN4I_GPADC_CTRL2				0x08

--
To unsubscribe from this list: send the line "unsubscribe linux-iio"

in

quoted

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