[PATCH 0/2] iio: adc: Add Texas Instruments ADS1220 ADC

[Nguyen Minh Tien]

This series adds support for the Texas Instruments ADS1220, a 24-bit,
2-kSPS, 4-channel delta-sigma ADC with an SPI (mode 1) interface, a
programmable gain amplifier (1 to 128), an internal 2.048V reference and
a dedicated DRDY data-ready output.

The driver supports:
 - single-ended and differential voltage channels described as
   device-tree child nodes;
 - per-channel programmable gain (via _scale) and data rate (via
   _sampling_frequency), with the matching *_available attributes;
 - the internal 2.048V reference, an external reference on REFP0/REFN0
   via a regulator, or the analog supply (AVDD) as a ratiometric
   reference for single-supply measurements;
 - single-shot conversions gated on the DRDY interrupt, or on a
   data-rate-derived delay when no interrupt is wired;
 - a DRDY-interrupt-driven triggered buffer for streaming;
 - runtime PM (power-down between conversions).

I tested this on a Lichee Pi Nano (Allwinner F1C100s) running Linux 7.0:
with a potentiometer on AIN0 (single-ended against AVSS, AVDD as the
reference), in_voltage0_raw tracks the wiper linearly across the full
0..3.3V range (0 to 0x7fffff). Nothing in the driver is board-specific -
it only uses the SPI and IIO frameworks - so it should work on any SPI
host.

This is my first kernel contribution. I modelled the driver on the
existing TI ADS-family IIO drivers - ti-ads1119 for the structure and
ti-ads124s08 for the SPI side - so I'd welcome any feedback on things
I've missed.

Nguyen Minh Tien (2):
  dt-bindings: iio: adc: Add TI ADS1220
  iio: adc: Add TI ADS1220 driver

 .../bindings/iio/adc/ti,ads1220.yaml          | 146 +++
 MAINTAINERS                                   |   7 +
 drivers/iio/adc/Kconfig                       |  12 +
 drivers/iio/adc/Makefile                      |   1 +
 drivers/iio/adc/ti-ads1220.c                  | 835 ++++++++++++++++++
 5 files changed, 1001 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,ads1220.yaml
 create mode 100644 drivers/iio/adc/ti-ads1220.c


base-commit: ae696dfa47c30016cd429b9db5e70b259b8f509e
-- 
2.34.1