From 613cbb91e9cee7cf5a61f0816d2acab7bc117407 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 27 Jun 2023 14:51:04 +0200 Subject: media: Add MIPI CCI register access helper functions 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 Tested-by: Tommaso Merciai Reviewed-by: Tommaso Merciai Signed-off-by: Hans de Goede Signed-off-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- Documentation/driver-api/media/v4l2-cci.rst | 5 +++++ 1 file changed, 5 insertions(+) create mode 100644 Documentation/driver-api/media/v4l2-cci.rst (limited to 'Documentation/driver-api/media/v4l2-cci.rst') diff --git a/Documentation/driver-api/media/v4l2-cci.rst b/Documentation/driver-api/media/v4l2-cci.rst new file mode 100644 index 000000000000..dd297a40ed20 --- /dev/null +++ b/Documentation/driver-api/media/v4l2-cci.rst @@ -0,0 +1,5 @@ +.. SPDX-License-Identifier: GPL-2.0 + +V4L2 CCI kAPI +^^^^^^^^^^^^^ +.. kernel-doc:: include/media/v4l2-cci.h -- cgit v1.2.3