lib/vsprintf: Add support for printing V4L2 and DRM fourccs
Add a printk modifier %p4cc (for pixel format) for printing V4L2 and DRM
pixel formats denoted by fourccs. The fourcc encoding is the same for both
so the same implementation can be used.
Suggested-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210216155723.17109-2-sakari.ailus@linux.intel.com
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 160e710..8267675 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -567,6 +567,24 @@
Passed by reference.
+V4L2 and DRM FourCC code (pixel format)
+---------------------------------------
+
+::
+
+ %p4cc
+
+Print a FourCC code used by V4L2 or DRM, including format endianness and
+its numerical value as hexadecimal.
+
+Passed by reference.
+
+Examples::
+
+ %p4cc BG12 little-endian (0x32314742)
+ %p4cc Y10 little-endian (0x20303159)
+ %p4cc NV12 big-endian (0xb231564e)
+
Thanks
======
