[PATCH 0/9] iio: adc: ad9467: add debugFS test mode support

[Nuno Sa <nuno.sa@analog.com>]

This series adds support for testing the digital interface on ad9467
using different test patterns/modes. For doing it, debugFS support for
backends is also added. Notably:

* backend direct reg access which is not directly needed for the ad9467
  new interface but it's something useful to have (the same as IIO
  direct_reg_access for "normal" IIO devices) and something that I would
  eventually try to add anyways.
* printing channel status which is useful for more verbose information
  about some possible failure in the test pattern. 

The first couple of patches are unrelated but simple enough that
I placed them in this patchset.

---
Nuno Sa (9):
      iio: backend: remove unused parameter
      iio: backend: print message in case op is not implemented
      iio: backend: add debugFs interface
      iio: backend: add a modified prbs23 support
      iio: adc: adi-axi-adc: support modified prbs23
      iio: adc: adi-axi-adc: split axi_adc_chan_status()
      iio: adc: adi-axi-adc: implement backend debugfs interface
      iio: adc: ad9467: add backend test mode helpers
      iio: adc: ad9467: add digital interface test to debugfs

 drivers/iio/adc/ad9467.c           | 255 +++++++++++++++++++++++++++++++++----
 drivers/iio/adc/adi-axi-adc.c      |  64 +++++++++-
 drivers/iio/dac/ad9739a.c          |   3 +-
 drivers/iio/industrialio-backend.c | 123 +++++++++++++++++-
 include/linux/iio/backend.h        |  21 ++-
 5 files changed, 428 insertions(+), 38 deletions(-)
---
base-commit: 986da024b99a72e64f6bdb3f3f0e52af024b1f50
change-id: 20240709-dev-iio-backend-add-debugfs-ef7cd2007073
--

Thanks!
- Nuno Sá