[PATCH v6 0/2] iio: Add support for TI ADS1X18 ADCs

[Kurt Borja <kuurtb@gmail.com>]

Hi,

This series adds a new driver for TI ADS1X18 SPI devices.

This is my first time contributing to the IIO subsystem and making
dt-bindings documentation, so (don't) go easy on me :p.

As explained in Patch 2 changelog, the DRDY interrupt line is shared
with the MOSI pin. This awkward quirk is also found on some Analog
Devices sigma-delta SPI ADCs, so the interrupt and trigger design is
inspired by those.

Thank you in advance for your reviews.

Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
v2:
  - [Patch 1]:
    - Move MAINTAINERS change here
    - Use generic node names: ads1118@0 -> adc@0
    - Rename file to ti,ads1118.yaml -> ti,ads1018.yaml
    - Drop ti,gain and ti,datarate
    - Add spi-cpha and spi-max-frecuency properties as they are fixed in
      all models
    - Add vdd-supply
    - Make interrupts and drdy-gpios optional properties

  - [Patch 2]:
    - Update probe based on dt-bindings changes
    - Rename file to ti-ads1x18.c -> ti-ads1018.c
    - Rework ads1018_oneshot(), instead of waiting for IRQ wait an
      appropriate delay before reading again
    - Only alloc and register a trigger if we have an IRQ line
    - Drop ads1x18->msg_lock in favor of IIO API locks
    - Read conver before enabling and after disabling IRQ to ensure CS
      state is correct
    - Add ads1018_read_locked() which takes an additional argument
      `hold_cs` to explicitly control CS state in trigger and buffer
    - Fix ADS1X18_CHANNELS_MAX limit 9 -> 10
    - Call iio_trigger_notify_done() in all IRQ handler paths
    - Drop unused includes
    - Drop BIT_U16 and GENMASK_U16 macros
    - Drop unnecessary named defines
    - Use u8 types in ads1018_chan_data
    - Rename some struct members for clarity
    - Move tx_buf and rx_buf to the end of struct ads1018
    - Rework channel handling to just make everything visible and add
      ADS1018_VOLT_DIFF_CHAN
    - Use .scan_index instead of .address in IIO channels
    
  - v1: https://lore.kernel.org/r/20251121-ads1x18-v1-0-86db080fc9a4@gmail.com

---
v3:
  - [Patch 1]:
    - Use unevaluatedProperties: false
    - Drop #address-cells and #size-cells

  - [Patch 2]:
    - Add kernel-doc to internal API
    - Drop bits.h and bitops.h includes
    - Add types.h include
    - Use unsigned type for data_rate_mode_to_hz
    - Rename __ads1018_read_raw() -> ads1018_read_raw_unlocked()
    - Rename __ads1018_write_raw() -> ads1018_write_raw_unlocked()
    - Rename ads1018_read_locked -> ads1018_read_unlocked() for
      consistency
    - Let ads1018_read_unlocked() take NULL cnv pointers
    - Add ads1018_set_trigger_{enable,disable}()
    - Refactor ads1018_write_raw_unlocked() loop matching
    - Invert ads1018_trigger_handler() logic to follow traditional error
      handling pattern
    - Refactor ads1018_trigger_setup() cleaner
    - Make ADS1018_FSR_TO_SCALE() calculation be 32-bit compatible
    - Some additionall minor cleanups

  - Link to v2: https://lore.kernel.org/r/20251127-ads1x18-v2-0-2ebfd780b633@gmail.com

---
v4:
  - [Patch 2]:
    - Replaced <linux/byteorder/generic.h> -> <asm/byteorder.h>
    - Dropped ADS1018_CFG_DEFAULT
    - Fixed long lines
    - Added Andy's remark on ADS1018_FSR_TO_SCALE() kernel-doc
      description.
    - Fixed wrong argument on iio_trigger_notify_done():
      ads1018->indio_trig -> indio_dev->trig
    - Renamed argument in channel macros _addr -> _index
    - Changed return type of ads1018_calc_delay() to u32
    - Mention @cnv is optional in ads1018_read_unlocked()
    - Use 16-bit transmission cycle in ads1018_oneshot()
    - Dropped spi_set_drvdata()
    - Use full resolution in ADS1018_FSR_TO_SCALE() and subtract 1
      inside macro
    - Rename ads1018_read_locked() -> ads1018_spi_read_exclusive() for
      clarity
    - Minor style changes

  - Link to v3: https://lore.kernel.org/r/20251128-ads1x18-v3-0-a6ebab815b2d@gmail.com

---
v5:
  - [Patch 2]:
    - Fix ADS1018_FSR_TO_SCALE() long description
    - In ADS1018_FSR_TO_SCALE() subtract 6 from BIT() argument instead
      of shifting the value

  - Link to v4: https://lore.kernel.org/r/20251202-ads1x18-v4-0-8c3580bc273f@gmail.com

---
v6:
  - [Patch 2]:
    - Actually make the changes described above. Sorry for the noise :(.

  - Link to v5: https://lore.kernel.org/r/20251204-ads1x18-v5-0-b6243de766d1@gmail.com

---
Kurt Borja (2):
      dt-bindings: iio: adc: Add TI ADS1018/ADS1118
      iio: adc: Add ti-ads1018 driver

 .../devicetree/bindings/iio/adc/ti,ads1018.yaml    |  82 ++
 MAINTAINERS                                        |   7 +
 drivers/iio/adc/Kconfig                            |  12 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/ti-ads1018.c                       | 826 +++++++++++++++++++++
 5 files changed, 928 insertions(+)
---
base-commit: f9e05791642810a0cf6237d39fafd6fec5e0b4bb
change-id: 20251012-ads1x18-0d0779d06690

-- 
 ~ Kurt