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Commit 9bcf15f7 authored by Hans de Goede's avatar Hans de Goede Committed by Jonathan Cameron
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iio: adc: axp288: Fix TS-pin handling 

Prior to this commit there were 3 issues with our handling of the TS-pin:

1) There are 2 ways how the firmware can disable monitoring of the TS-pin
for designs which do not have a temperature-sensor for the battery:
a) Clearing bit 0 of the AXP20X_ADC_EN1 register
b) Setting bit 2 of the AXP288_ADC_TS_PIN_CTRL monitoring

Prior to this commit we were unconditionally setting both bits to the
value used on devices with a TS. This causes the temperature protection to
kick in on devices without a TS, such as the Jumper ezbook v2, causing
them to not charge under Linux.

This commit fixes this by using regmap_update_bits when updating these 2
registers, leaving the 2 mentioned bits alone.

The next 2 problems are related to our handling of the current-source
for the TS-pin. The current-source used for the battery temp-sensor (TS)
is shared with the GPADC. For proper fuel-gauge and charger operation the
TS current-source needs to be permanently on. But to read the GPADC we
need to temporary switch the TS current-source to ondemand, so that the
GPADC can use it, otherwise we will always read an all 0 value.

2) Problem 2 is we were writing hardcoded values to the ADC TS pin-ctrl
register, overwriting various other unrelated bits. Specifically we were
overwriting the current-source setting for the TS and GPIO0 pins, forcing
it to 80ųA independent of its original setting. On a Chuwi Vi10 tablet
this was causing us to get a too high adc value (due to a too high
current-source) resulting in the following errors being logged:

ACPI Error: AE_ERROR, Returned by Handler for [UserDefinedRegion]
ACPI Error: Method parse/execution failed \_SB.SXP1._TMP, AE_ERROR

This commit fixes this by using regmap_update_bits to change only the
relevant bits.

3) After reading the GPADC channel we were unconditionally enabling the
TS current-source even on devices where the TS-pin is not used and the
current-source thus was off before axp288_adc_read_raw call.

This commit fixes this by making axp288_adc_set_ts a nop on devices where
the ADC is not enabled for the TS-pin.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1610545


Fixes: 3091141d ("iio: adc: axp288: Fix the GPADC pin ...")
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 0808831d

drivers/iio/adc/axp288_adc.c

+60 −16
Original line number Diff line number Diff line
@@ -27,9 +27,18 @@ 
#include <linux/iio/machine.h>

#include <linux/iio/driver.h>



#define AXP288_ADC_EN_MASK		0xF1

#define AXP288_ADC_TS_PIN_GPADC		0xF2

#define AXP288_ADC_TS_PIN_ON		0xF3

/*

 * This mask enables all ADCs except for the battery temp-sensor (TS), that is

 * left as-is to avoid breaking charging on devices without a temp-sensor.

 */

#define AXP288_ADC_EN_MASK				0xF0

#define AXP288_ADC_TS_ENABLE				0x01



#define AXP288_ADC_TS_CURRENT_ON_OFF_MASK		GENMASK(1, 0)

#define AXP288_ADC_TS_CURRENT_OFF			(0 << 0)

#define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING		(1 << 0)

#define AXP288_ADC_TS_CURRENT_ON_ONDEMAND		(2 << 0)

#define AXP288_ADC_TS_CURRENT_ON			(3 << 0)



enum axp288_adc_id {

	AXP288_ADC_TS,
@@ -44,6 +53,7 @@ enum axp288_adc_id { 
struct axp288_adc_info {

	int irq;

	struct regmap *regmap;

	bool ts_enabled;

};



static const struct iio_chan_spec axp288_adc_channels[] = {
@@ -115,21 +125,33 @@ static int axp288_adc_read_channel(int *val, unsigned long address, 
	return IIO_VAL_INT;

}



static int axp288_adc_set_ts(struct regmap *regmap, unsigned int mode,

				unsigned long address)

/*

 * The current-source used for the battery temp-sensor (TS) is shared

 * with the GPADC. For proper fuel-gauge and charger operation the TS

 * current-source needs to be permanently on. But to read the GPADC we

 * need to temporary switch the TS current-source to ondemand, so that

 * the GPADC can use it, otherwise we will always read an all 0 value.

 */

static int axp288_adc_set_ts(struct axp288_adc_info *info,

			     unsigned int mode, unsigned long address)

{

	int ret;



	/* channels other than GPADC do not need to switch TS pin */

	/* No need to switch the current-source if the TS pin is disabled */

	if (!info->ts_enabled)

		return 0;



	/* Channels other than GPADC do not need the current source */

	if (address != AXP288_GP_ADC_H)

		return 0;



	ret = regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, mode);

	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,

				 AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);

	if (ret)

		return ret;



	/* When switching to the GPADC pin give things some time to settle */

	if (mode == AXP288_ADC_TS_PIN_GPADC)

	if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)

		usleep_range(6000, 10000);



	return 0;
@@ -145,14 +167,14 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev, 
	mutex_lock(&indio_dev->mlock);

	switch (mask) {

	case IIO_CHAN_INFO_RAW:

		if (axp288_adc_set_ts(info->regmap, AXP288_ADC_TS_PIN_GPADC,

		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,

					chan->address)) {

			dev_err(&indio_dev->dev, "GPADC mode\n");

			ret = -EINVAL;

			break;

		}

		ret = axp288_adc_read_channel(val, chan->address, info->regmap);

		if (axp288_adc_set_ts(info->regmap, AXP288_ADC_TS_PIN_ON,

		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,

						chan->address))

			dev_err(&indio_dev->dev, "TS pin restore\n");

		break;
@@ -164,13 +186,35 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev, 
	return ret;

}



static int axp288_adc_set_state(struct regmap *regmap)

static int axp288_adc_initialize(struct axp288_adc_info *info)

{

	/* ADC should be always enabled for internal FG to function */

	if (regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, AXP288_ADC_TS_PIN_ON))

		return -EIO;

	int ret, adc_enable_val;



	/*

	 * Determine if the TS pin is enabled and set the TS current-source

	 * accordingly.

	 */

	ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);

	if (ret)

		return ret;



	if (adc_enable_val & AXP288_ADC_TS_ENABLE) {

		info->ts_enabled = true;

		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,

					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,

					 AXP288_ADC_TS_CURRENT_ON);

	} else {

		info->ts_enabled = false;

		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,

					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,

					 AXP288_ADC_TS_CURRENT_OFF);

	}

	if (ret)

		return ret;



	return regmap_write(regmap, AXP20X_ADC_EN1, AXP288_ADC_EN_MASK);

	/* Turn on the ADC for all channels except TS, leave TS as is */

	return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,

				  AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);

}



static const struct iio_info axp288_adc_iio_info = {
@@ -200,7 +244,7 @@ static int axp288_adc_probe(struct platform_device *pdev) 
	 * Set ADC to enabled state at all time, including system suspend.

	 * otherwise internal fuel gauge functionality may be affected.

	 */

	ret = axp288_adc_set_state(axp20x->regmap);

	ret = axp288_adc_initialize(info);

	if (ret) {

		dev_err(&pdev->dev, "unable to enable ADC device\n");

		return ret;