[PATCH v2 0/5] iio: adc: ad4000: Add SPI offload support

[Marcelo Schmitt <marcelo.schmitt@analog.com>]

This patch series extends the ad4000 driver to support SPI offloading.
In addition to that, ad4000 IIO documentation is expanded to:
- list PulSAR parts supported by the ad4000 driver.
- describe some characteristics of AD4000 IIO device.
- describe changes when SPI offload is being used.

v2 changes were tested with ADAQ4003 on CoraZ7 setup running Linux built from
IIO testing branch.

Link to v1: https://lore.kernel.org/linux-iio/cover.1741970538.git.marcelo.schmitt@analog.com/

Change log v1 -> v2
- Fixed passing inappropriate pointer instead of ret to dev_err_probe().
- [new patch] Set transfer bits_per_word to have data in CPU endianness.
- Set iio_dev num_channels close to where channels is set.
- Complement offload message comment about first sample being invalid.
- Documented why the first buffer sample is invalid when offloading.
- Added blank line before a 'simple return'. 

Instead of changing bits_per_word according to buffer endianness, I set
bits_per_word for other SPI transfers and updated IIO channels to always use CPU
endianness (the new patch). With that, bits_per_word no longer needs be updated
according to buffer endianness or, in other words, buffer endianness is no
longer related to bits_per_word.


Marcelo Schmitt (5):
  iio: adc: ad400: Set transfer bits_per_word to have data in CPU
    endianness
  iio: adc: ad4000: Add support for SPI offload
  Documentation: iio: ad4000: Add new supported parts
  Documentation: iio: ad4000: Add IIO Device characteristics section
  Documentation: iio: ad4000: Describe offload support

 Documentation/iio/ad4000.rst |  86 +++++-
 drivers/iio/adc/Kconfig      |   7 +-
 drivers/iio/adc/ad4000.c     | 509 +++++++++++++++++++++++++++++------
 3 files changed, 512 insertions(+), 90 deletions(-)


base-commit: af94f401e26f686f7391ce79b38a6129417c22dc
prerequisite-patch-id: 3d517eef53a799adba5922815fe684b913e36773
-- 
2.47.2