[PATCH v2 0/2] iio: adc: Add Nuvoton MA35D1 EADC support

[Chi-Wen Weng <cwweng.linux@gmail.com>]

From: Chi-Wen Weng <cwweng@nuvoton.com>

This series adds devicetree binding and IIO driver support for the
Nuvoton MA35D1 Enhanced ADC controller.

The MA35D1 EADC controller supports external analog input channels,
fixed differential input pairs, an optional external reference voltage,
up to four end-of-conversion interrupts, an optional reset line, and an
ADC-to-memory DMA request.

This initial driver supports interrupt-driven direct raw reads and
triggered buffered capture. Buffered capture is paced by an external IIO
trigger and is limited to a single enabled voltage channel per scan in
this version. Multi-channel buffered scans and DMA support can be added
later.

The driver supports both single-ended external channels and the fixed
hardware differential input pairs. Differential conversions are reported
as signed two's complement values. The ADC scale is reported using either
the optional external vref-supply or the internal 1.6 V reference.

Changes in v2:
- Update the binding to allow up to four interrupt entries for ADINT0 to
  ADINT3.
- Add optional vref-supply, dmas, dma-names and resets properties to the
  binding.
- Keep diff-channels in the binding and restrict differential inputs to
  the fixed hardware pairs.
- Limit DT child channel nodes to external channels 0 to 7.
- Use regmap for register access.
- Add optional reset handling.
- Add optional external reference handling and IIO scale reporting.
- Use the internal 1.6 V reference when no vref-supply is present.
- Handle differential conversions as signed two's complement values.
- Use an external IIO trigger for buffered capture instead of a
  self-retriggering EOC loop.
- Limit buffered capture to a single enabled voltage channel per scan.
- Rework suspend and resume to save and restore the buffered capture
  state.
- Use devm_mutex_init() and scoped child-node iteration.
- Use the new scan_type.format field for buffered scan type metadata.
- Drop datasheet_name from channel setup.
- Address header, helper naming and cleanup comments from review.

Chi-Wen Weng (2):
  dt-bindings: iio: adc: Add Nuvoton MA35D1 EADC
  iio: adc: Add Nuvoton MA35D1 EADC driver

 .../bindings/iio/adc/nuvoton,ma35d1-eadc.yaml | 163 ++++
 drivers/iio/adc/Kconfig                       |  12 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ma35d1_eadc.c                 | 740 ++++++++++++++++++
 4 files changed, 916 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
 create mode 100644 drivers/iio/adc/ma35d1_eadc.c

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2.25.1