iio: adc: Revert "axp288: Drop bogus AXP288_ADC_TS_PIN_CTRL register modifications"

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>

diff --git a/drivers/iio/adc/axp288_adc.c b/drivers/iio/adc/axp288_adc.c
index 64799ad7ebad02a797607470678aa500842ed99f..7fd24949c0c14fb53cb3d6f37a8d1d6afa1c0f0e 100644 (file)
--- 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;