[PATCH v3 0/5] iio: ad3552r-hs: add support for internal ramp generator

[Angelo Dureghello]

Add support to enable the HDL IP core internal ramp generator,
actually managed by the adi-axi-dac backend. 

It works this way:

/sys/bus/iio/devices/iio:device0# echo 1 > buffer0/out_voltage0_en 
/sys/bus/iio/devices/iio:device0# echo 1 > buffer0/out_voltage1_en                                           
/sys/bus/iio/devices/iio:device0# echo 1 > buffer0/enable 

Activating ramp generator:

/sys/kernel/debug/iio/iio:device0# echo -n backend-ramp-generator > data_source

Deactivating:

/sys/kernel/debug/iio/iio:device0# echo -n iio-buffer > data_source

Signed-off-by: Angelo Dureghello <adureghello@xxxxxxxxxxxx>
---
Changes in v3:
- add mutex description,
- use devm_mutex_init and check for return value.
- Link to v2: https://lore.kernel.org/r/20250331-wip-bl-ad3552r-fixes-v2-0-cdedb430497e@xxxxxxxxxxxx

Changes in v2:
- doc, add few words for generic spi driver version,
- axi-dac, add a separate patch to check cntrl chan validity,
- axi-dac, return EIO on a wrong source on get, 
- add a lock on debugfs file access,
- use const strings and strlen on file access.
- Link to v1: https://lore.kernel.org/r/20250321-wip-bl-ad3552r-fixes-v1-0-3c1aa249d163@xxxxxxxxxxxx

---
Angelo Dureghello (5):
      iio: dac: adi-axi-dac: add cntrl chan check
      docs: iio: add documentation for ad3552r driver
      iio: backend: add support for data source get
      iio: dac: adi-axi-dac: add data source get
      iio: dac: ad3552r-hs: add support for internal ramp

 Documentation/iio/ad3552r.rst      |  72 +++++++++++++++++++++
 Documentation/iio/index.rst        |   1 +
 MAINTAINERS                        |   1 +
 drivers/iio/dac/ad3552r-hs.c       | 124 +++++++++++++++++++++++++++++++++++--
 drivers/iio/dac/adi-axi-dac.c      |  54 ++++++++++++++++
 drivers/iio/industrialio-backend.c |  28 +++++++++
 include/linux/iio/backend.h        |   5 ++
 7 files changed, 279 insertions(+), 6 deletions(-)
---
base-commit: eb870a5af7db1e5ca59330875125230b28e630f9
change-id: 20250321-wip-bl-ad3552r-fixes-4a386944c170

Best regards,
-- 
Angelo Dureghello <adureghello@xxxxxxxxxxxx>