[PATCH RFC v2 0/2] iio: adc: ad7173: add ad4111 openwire detection support

[Guillaume Ranquet <granquet@baylibre.com>]

Hi.

This patch adds the openwire detection support for the ad4111 chip.

The openwire detection is done in software and relies on comparing the
results of two conversions on different channels.

Following the discussion in the RFC V1, I'm taking the easy route of
adding a new event type  called IIO_EV_TYPE_OPENWIRE to signal the
condition to the userland.

I have chosen this option rather than the generic TRACE_EVENT() solution
exposed by Jonathan because this change is more contained and only
impacts the iio subsystem.

The TRACE_EVENT() option, although more generic, will require a lot of
discussion between involved parties and is probably easier to tackle in
person than through the mailing list?

The openwire detection on ad4111 is triggered automatically when a
single conversion is requested.
Due to the way openwire detection works on ad4111, implementing openwire
detection for continuous conversion mode is more complicated.

Thx,
Guillaume.

Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
---
Changes in v2:
- Introduce IIO_EV_TYPE_OPENWIRE instead of misusing the IIO_EV_THRESH
  event.
- Link to v1: https://lore.kernel.org/r/20241115-ad4111_openwire-v1-1-db97ac8bf250@baylibre.com

---
Guillaume Ranquet (2):
      iio: introduce the OPENWIRE event type
      iio: adc: ad7173: add openwire detection support for single conversions

 drivers/iio/adc/ad7173.c         | 164 +++++++++++++++++++++++++++++++++++++++
 drivers/iio/industrialio-event.c |   1 +
 include/uapi/linux/iio/types.h   |   1 +
 tools/iio/iio_event_monitor.c    |   2 +
 4 files changed, 168 insertions(+)
---
base-commit: c849f534b9ea4688304f80f4571af75931dda7c1
change-id: 20241115-ad4111_openwire-e55deba8297f
prerequisite-message-id: <20241115-ad411x_calibration-v1-1-5f820dfb5c80@baylibre.com>
prerequisite-patch-id: 26241903b8fee8c4243e73d11fb2872cd9f52a15

Best regards,
-- 
Guillaume Ranquet <granquet@baylibre.com>