[PATCH v9 0/6] iio: adc: Add support for LTC2378 and similar ADCs

This patch series adds support for LTC2378 and similar low noise, low power,
high speed, successive approximation register (SAR) ADCs. These ADCs are similar
among each other, varying mainly on the amount of precision bits, maximum sample
rate, and input configuration (either fully differential or pseudo-differential).

Patch 1 adds device tree documentation for LTC2378.

Patch 2 enables single-shot sample read with a GPIO connected to the LTC2378 CNV pin.

Patch 3 enables high-speed data captures with SPI offloading.
The setup is similar to AD4030, with a specialized PWM generator being used both
for SPI offload triggering and conversion start signaling.

Patch 4 enables running buffered data captures without SPI offloading.

Patch 5 adds support for LTC2338-18.

Patch 6 recommends using voltageY-voltageZ ABI for differential parts.

Even though these parts are somewhat similar to AD4000, the wiring configuration
for LTC parts is different as well as the available HDL for high speed sample
rate mode. Because of that, I propose creating a new device driver for
supporting LTC2378-like devices.

Specifications can be found at:
https://www.analog.com/media/en/technical-documentation/data-sheets/233818fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236416fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236418f.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236716fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236718f.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236816f.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236818f.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/236918fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237016fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237616fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237618fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237620fb.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237716fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237718fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237720fb.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237816fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237818fa.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237820fb.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/237918fb.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/238016fb.pdf

Previous submissions:
  v8: https://lore.kernel.org/linux-iio/[email protected]/
  v7: https://lore.kernel.org/linux-iio/[email protected]/
  v6: https://lore.kernel.org/linux-iio/[email protected]/
  v5: https://lore.kernel.org/linux-iio/[email protected]/
  v4: https://lore.kernel.org/linux-iio/[email protected]/
  v3: https://lore.kernel.org/linux-iio/[email protected]/
  v2: https://lore.kernel.org/linux-iio/[email protected]/
  v1: https://lore.kernel.org/linux-iio/[email protected]/

Change log v8 -> v9:
[DT]
No changes in device tree doc.
[IIO]
- Took LTC2338-18 input attenuation effect into account for _scale calculation.
- Split LTC2338-18 into a separate new patch.

With best regards,
Marcelo


Marcelo Schmitt (6):
  dt-bindings: iio: adc: Add ltc2378
  iio: adc: ltc2378: Add support for LTC2378-20 and similar ADCs
  iio: adc: ltc2378: Enable high-speed data capture
  iio: adc: ltc2378: Enable triggered buffer data capture
  iio: adc: ltc2378: Add support for LTC2338-18
  iio: ABI: Encourage differential voltage ABI usage

 Documentation/ABI/testing/sysfs-bus-iio       |   9 +-
 .../bindings/iio/adc/adi,ltc2378.yaml         | 170 ++++
 MAINTAINERS                                   |   8 +
 drivers/iio/adc/Kconfig                       |  19 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ltc2378.c                     | 856 ++++++++++++++++++
 6 files changed, 1059 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ltc2378.yaml
 create mode 100644 drivers/iio/adc/ltc2378.c


base-commit: aa58ecc73466d0cb8c418de98e2225490bf600e3
-- 
2.53.0