Here comes another series for adding SPI offload support to an ADC.

The primary target is AD411x, but since this uses the ad_sigma_delta
shared module, a lot of this series is focused on that.

To start with, we have some cleanups to the ad_sigma_delta code, so feel
free to pick these up as they are ready as they generally stand on their
own.

Then before adding proper SPI offload support, we make use of
spi_optimize_message() to reduce CPU usage of all users of this driver
during buffered reads.

Also there is a new dt-binding and driver for a special SPI offload
trigger FPGA IP core that is used in this particular setup.

Then finally actual SPI offload support is added to the ad_sigma_delta
module and the ad7173 driver.

This was tested using EVAL-AD4112ARDZ on a DE10-Nano.

---
Changes in v2:
- New patch to fix overallocation of buffer size. [1/11]
- Also change int64_t to s64. [3/11]
- Fix typo in commit message. [4/11]
- Factor out scan_type to reduce line wraps. [4/11]
- New patch to clean up include more. [5/11]
- Duplicate comment about odd case of 24-bit data. [7/11]
- Fixed missing MODULE_IMPORT_NS() [10/11]
- Link to v1: https://lore.kernel.org/r/20250620-iio-adc-ad7173-add-spi-offload-support-v1-0-0766f6297430@baylibre.com

---
David Lechner (11):
      iio: adc: ad_sigma_delta: don't overallocate scan buffer
      iio: adc: ad_sigma_delta: sort includes
      iio: adc: ad_sigma_delta: use u8 instead of uint8_t
      iio: adc: ad_sigma_delta: use BITS_TO_BYTES() macro
      iio: adc: ad_sigma_delta: audit included headers
      iio: adc: ad_sigma_delta: refactor setting read address
      iio: adc: ad_sigma_delta: use spi_optimize_message()
      dt-bindings: trigger-source: add ADI Util Sigma-Delta SPI
      spi: offload trigger: add ADI Util Sigma-Delta SPI driver
      iio: adc: ad_sigma_delta: add SPI offload support
      iio: adc: ad7173: add SPI offload support

 .../trigger-source/adi,util-sigma-delta-spi.yaml   |  49 ++++
 MAINTAINERS                                        |   7 +-
 drivers/iio/adc/ad7173.c                           |  13 +
 drivers/iio/adc/ad_sigma_delta.c                   | 294 +++++++++++++--------
 drivers/spi/Kconfig                                |   5 +
 drivers/spi/Makefile                               |   1 +
 .../spi/spi-offload-trigger-adi-util-sigma-delta.c |  59 +++++
 include/linux/iio/adc/ad_sigma_delta.h             |  27 +-
 8 files changed, 341 insertions(+), 114 deletions(-)
---
base-commit: d02f330b0c78bcf76643fbb7d3215a58b181f829
change-id: 20250620-iio-adc-ad7173-add-spi-offload-support-32a178b666a3

Best regards,
-- 
David Lechner <dlechner@baylibre.com>

On Fri, 27 Jun 2025 18:39:56 -0500, David Lechner wrote:
> Here comes another series for adding SPI offload support to an ADC.
> 
> The primary target is AD411x, but since this uses the ad_sigma_delta
> shared module, a lot of this series is focused on that.
> 
> To start with, we have some cleanups to the ad_sigma_delta code, so feel
> free to pick these up as they are ready as they generally stand on their
> own.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[08/11] dt-bindings: trigger-source: add ADI Util Sigma-Delta SPI
        commit: e47a324d6f07c9ef252cfce1f14cfa5110cbed99
[09/11] spi: offload trigger: add ADI Util Sigma-Delta SPI driver
        commit: 3fcd3d2fe44dc9dfca20b6aed117f314a50ba0ff

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark