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.
The switching from on to on-ondemand is not necessary when the TS
current-source is off (this happens on devices which do not have a TS).
Prior to this commit there were 2 issues with our handling of the TS
current-source switching:
1) 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 acpi_lpat_raw_to_temp() returning -ENOENT, resulting in:
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.
2) At the end of intel_xpower_pmic_get_raw_temp() 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 on entry of the function.
This commit fixes this by checking if the TS current-source is off when
entering intel_xpower_pmic_get_raw_temp() and if so it is left as is.
Fixes: 58eefe2f3f (ACPI / PMIC: xpower: Do pinswitch ... reading GPADC)
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: 4.14+ <stable@vger.kernel.org> # 4.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2b531d7159