[media] v4l2-ctrl: Add helper function for the controls range update

This patch adds a helper function that allows to modify range,
i.e. minimum, maximum, step and default value of a v4l2 control,
after the control has been created and initialized. This is helpful
in situations when range of a control depends on user configurable
parameters, e.g. camera sensor absolute exposure time depending on
an output image resolution and frame rate.
v4l2_ctrl_modify_range() function allows to modify range of an
INTEGER, BOOL, MENU, INTEGER_MENU and BITMASK type controls.
Based on a patch from Hans Verkuil http://patchwork.linuxtv.org/patch/8654.

Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 94cbe26e9f00..928799c2e2d9 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -1822,6 +1822,7 @@ struct v4l2_event_vsync {
 /* Payload for V4L2_EVENT_CTRL */
 #define V4L2_EVENT_CTRL_CH_VALUE                (1 << 0)
 #define V4L2_EVENT_CTRL_CH_FLAGS                (1 << 1)
+#define V4L2_EVENT_CTRL_CH_RANGE                (1 << 2)
 
 struct v4l2_event_ctrl {
         __u32 changes;