This series adds support for reading channel labels from the device tree
in the Qualcomm PM8xxx XOADC driver, along with the corresponding DT
updates for the PM8921 PMIC. Also removes the redundant error logs when
reading values, as returning -EINVAL and -ETIMEDOUT are sufficient to
report failures.

Tested on Sony Xperia SP (PM8921):
> cat /sys/bus/iio/devices/iio\:device0/in_voltage7_label
usb_vbus
> cat /sys/bus/iio/devices/iio\:device0/in_temp12_label
ref_muxoff
> sensors
iio_hwmon-isa-0000
Adapter: ISA adapter
vbat:        267.86 V
dcin:          4.82 kV
...
chg_temp:    +1071.4°C

Note: the sensor readings above are incorrect due to pending calibration
fixes are not included in this series. This patch only addresses label
visibility. The values are expected to be wrong until the calibration
fixes lands separately.

Signed-off-by: Antony Kurniawan Soemardi <linux@smankusors.com>
---
Changes in v3:
- Simplify label assignment logic by removing the unnecessary
  conditional branch.
- Remove redundant error logging in pm8xxx_read_channel_rsv, since
  -ETIMEDOUT is sufficient to report failures.
- Link to v2: https://lore.kernel.org/r/20260403-pm8xxx-xoadc-label-v2-0-29b50bf821e6@smankusors.com

Changes in v2:
- Remove redundant error logging in pm8xxx_read_raw, since -EINVAL is
  sufficient to report failures.
- Reword the uncommon Tested-by commit tag to freeform text
- Link to v1: https://lore.kernel.org/r/20260326-pm8xxx-xoadc-label-v1-0-027805dad4db@smankusors.com

Changes since original patch:
- The label is now read from the platform description (device tree)
  instead of the internal datasheet name.
- Link to original patch:
  https://lore.kernel.org/all/20251028-pm8xxx-xoadc-fix-v1-1-b000e1036e41@smankusors.com/

---
Antony Kurniawan Soemardi (3):
      ARM: dts: qcom: pm8921: add labels for ADC channels
      iio: adc: qcom-pm8xxx-xoadc: remove redundant error logs when reading values
      iio: adc: qcom-pm8xxx-xoadc: add support for reading channel labels

 arch/arm/boot/dts/qcom/pm8921.dtsi  | 12 ++++++++++++
 drivers/iio/adc/qcom-pm8xxx-xoadc.c | 34 ++++++++++++++++++++--------------
 2 files changed, 32 insertions(+), 14 deletions(-)
---
base-commit: 5619b098e2fbf3a23bf13d91897056a1fe238c6d
change-id: 20260321-pm8xxx-xoadc-label-47afdf7f06a9

Best regards,
--
Antony Kurniawan Soemardi <linux@smankusors.com>