The CSI2 specification specifies a standard method to access camera sensor
registers called "Camera Control Interface (CCI)".
This uses either 8 or 16 bit (big-endian wire order) register addresses
and supports 8, 16, 24 or 32 bit (big-endian wire order) register widths.
Currently a lot of Linux camera sensor drivers all have their own custom
helpers for this, often copy and pasted from other drivers.
Add a set of generic helpers for this so that all sensor drivers can
switch to a single common implementation.
These helpers take an extra optional "int *err" function parameter,
this can be used to chain a bunch of register accesses together with
only a single error check at the end, rather than needing to error
check each individual register access. The first failing call will
set the contents of err to a non 0 value and all other calls will
then become no-ops.
Link: https://lore.kernel.org/linux-media/59aefa7f-7bf9-6736-6040-39551329cd0a@redhat.com/
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Tommaso Merciai <tomm.merciai@gmail.com>
Reviewed-by: Tommaso Merciai <tomm.merciai@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
