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Subject[PATCH 4.19 22/50] ACPI / PMIC: xpower: Fix TS-pin current-source handling
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hans de Goede <hdegoede@redhat.com>

commit 2b531d71595d2b5b12782a49b23c335869e2621e upstream.

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: 58eefe2f3f53 (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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/acpi/pmic/intel_pmic_xpower.c | 41 +++++++++++++++++++++++++++-------
1 file changed, 33 insertions(+), 8 deletions(-)

--- a/drivers/acpi/pmic/intel_pmic_xpower.c
+++ b/drivers/acpi/pmic/intel_pmic_xpower.c
@@ -27,8 +27,11 @@
#define GPI1_LDO_ON (3 << 0)
#define GPI1_LDO_OFF (4 << 0)

-#define AXP288_ADC_TS_PIN_GPADC 0xf2
-#define AXP288_ADC_TS_PIN_ON 0xf3
+#define AXP288_ADC_TS_CURRENT_ON_OFF_MASK GENMASK(1, 0)
+#define AXP288_ADC_TS_CURRENT_OFF (0 << 0)
+#define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING (1 << 0)
+#define AXP288_ADC_TS_CURRENT_ON_ONDEMAND (2 << 0)
+#define AXP288_ADC_TS_CURRENT_ON (3 << 0)

static struct pmic_table power_table[] = {
{
@@ -211,22 +214,44 @@ static int intel_xpower_pmic_update_powe
*/
static int intel_xpower_pmic_get_raw_temp(struct regmap *regmap, int reg)
{
+ int ret, adc_ts_pin_ctrl;
u8 buf[2];
- int ret;

- ret = regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL,
- AXP288_ADC_TS_PIN_GPADC);
+ /*
+ * 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.
+ *
+ * Note that the switching from on to on-ondemand is not necessary
+ * when the TS current-source is off (this happens on devices which
+ * do not use the TS-pin).
+ */
+ ret = regmap_read(regmap, AXP288_ADC_TS_PIN_CTRL, &adc_ts_pin_ctrl);
if (ret)
return ret;

- /* After switching to the GPADC pin give things some time to settle */
- usleep_range(6000, 10000);
+ if (adc_ts_pin_ctrl & AXP288_ADC_TS_CURRENT_ON_OFF_MASK) {
+ ret = regmap_update_bits(regmap, AXP288_ADC_TS_PIN_CTRL,
+ AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
+ AXP288_ADC_TS_CURRENT_ON_ONDEMAND);
+ if (ret)
+ return ret;
+
+ /* Wait a bit after switching the current-source */
+ usleep_range(6000, 10000);
+ }

ret = regmap_bulk_read(regmap, AXP288_GP_ADC_H, buf, 2);
if (ret == 0)
ret = (buf[0] << 4) + ((buf[1] >> 4) & 0x0f);

- regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, AXP288_ADC_TS_PIN_ON);
+ if (adc_ts_pin_ctrl & AXP288_ADC_TS_CURRENT_ON_OFF_MASK) {
+ regmap_update_bits(regmap, AXP288_ADC_TS_PIN_CTRL,
+ AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
+ AXP288_ADC_TS_CURRENT_ON);
+ }

return ret;
}

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