On Wed, Dec 14, 2016 at 9:55 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: > For some reason the axp288_adc driver was modifying the > AXP288_ADC_TS_PIN_CTRL register, changing bits 0-1 depending on > whether the GP_ADC channel or another channel was written. > > These bits control when a bias current is send to the TS_PIN, the > GP_ADC has its own pin and a separate bit in another register to > control the bias current. > > Not only does changing when to enable the TS_PIN bias current > (always or only when sampling) when reading the GP_ADC make no sense > at all, the code is modifying these bits is writing the entire register, > assuming that all the other bits have their default value. > > So if the firmware has configured a different bias-current for either > pin, then that change gets clobbered by the write, likewise if the > firmware has set bit 2 to indicate that the battery has no thermal sensor, > this will get clobbered by the write. > > This commit fixes all this, by simply removing all writes to the > AXP288_ADC_TS_PIN_CTRL register, they are not needed to read the > GP_ADC pin, and can actually be harmful. > > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Acked-by: Chen-Yu Tsai <wens@xxxxxxxx> Note that I do not have hardware to test this. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
