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:Hans de Goede <hdegoede@redhat.com> Cc: <Stable@vger.kernel.org> Signed-off-by: