[PATCH 4.9 086/171] iio: adc: Revert "axp288: Drop bogus AXP288_ADC_TS_PIN_CTRL register modifications"

Greg Kroah-Hartman
2018-11-08T22:05:28Z

[ Upstream commit 631b010abc5b57009c6a8328f51492665f6ef310 ]

Inheriting the ADC BIAS current settings from the BIOS instead of
hardcoding then causes the AXP288 to disable charging (I think it
mis-detects an overheated battery) on at least one model tablet.

So lets go back to hard coding the values, this reverts
commit fa2849e9649b ("iio: adc: axp288: Drop bogus
AXP288_ADC_TS_PIN_CTRL register modifications"), fixing charging not
working on the model tablet in question.

The exact cause is not fully understood, hence the revert to a known working
state.

Cc: stable@vger.kernel.org
Reported-by: Umberto Ixxo <sfumato1977@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/adc/axp288_adc.c | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/axp288_adc.c b/drivers/iio/adc/axp288_adc.c
index 64799ad7ebad..7fd24949c0c1 100644
--- a/drivers/iio/adc/axp288_adc.c
+++ b/drivers/iio/adc/axp288_adc.c
@@ -28,6 +28,8 @@
#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

enum axp288_adc_id {
AXP288_ADC_TS,
@@ -121,6 +123,16 @@ 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)
+{
+ /* channels other than GPADC do not need to switch TS pin */
+ if (address != AXP288_GP_ADC_H)
+ return 0;
+
+ return regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, mode);
+}
+
static int axp288_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
@@ -131,7 +143,16 @@ 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,
+ 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,
+ chan->address))
+ dev_err(&indio_dev->dev, "TS pin restore\n");
break;
default:
ret = -EINVAL;
@@ -141,6 +162,15 @@ static int axp288_adc_read_raw(struct iio_dev *indio_dev,
return ret;
}

+static int axp288_adc_set_state(struct regmap *regmap)
+{
+ /* 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;
+
+ return regmap_write(regmap, AXP20X_ADC_EN1, AXP288_ADC_EN_MASK);
+}
+
static const struct iio_info axp288_adc_iio_info = {
.read_raw = &axp288_adc_read_raw,
.driver_module = THIS_MODULE,
@@ -169,7 +199,7 @@ 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 = regmap_write(info->regmap, AXP20X_ADC_EN1, AXP288_ADC_EN_MASK);
+ ret = axp288_adc_set_state(axp20x->regmap);
if (ret) {
dev_err(&pdev->dev, "unable to enable ADC device\n");
return ret;
--
2.17.1