From d58083c949b3d76aba225be9f303ab5dab585064 Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Tue, 6 Mar 2012 07:06:55 -0300 Subject: [PATCH] [media] V4L: Add camera exposure bias control The camera may in some conditions incorrectly determine the exposure, and a manual automatic exposure correction may be needed. This patch adds V4L2_CID_AUTO_EXPOSURE_BIAS control which allows to add some offset in the automatic exposure control loop, to compensate for frame under- or over-exposure. Signed-off-by: Sylwester Nawrocki Signed-off-by: Kyungmin Park Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/controls.xml | 16 ++++++++++++++++ drivers/media/video/v4l2-ctrls.c | 4 ++++ include/linux/videodev2.h | 2 ++ 3 files changed, 22 insertions(+) diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml index e2ff0f98f08d..745b611c3593 100644 --- a/Documentation/DocBook/media/v4l/controls.xml +++ b/Documentation/DocBook/media/v4l/controls.xml @@ -2848,6 +2848,22 @@ remain constant. + + V4L2_CID_EXPOSURE_BIAS  + integer menu + Determines the automatic +exposure compensation, it is effective only when V4L2_CID_EXPOSURE_AUTO +control is set to AUTO, SHUTTER_PRIORITY +or APERTURE_PRIORITY. +It is expressed in terms of EV, drivers should interpret the values as 0.001 EV +units, where the value 1000 stands for +1 EV. +Increasing the exposure compensation value is equivalent to decreasing +the exposure value (EV) and will increase the amount of light at the image +sensor. The camera performs the exposure compensation by adjusting absolute +exposure time and/or aperture. + + + V4L2_CID_PAN_RELATIVE  integer diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c index fdcb9e21d9d3..5bfef90e88ee 100644 --- a/drivers/media/video/v4l2-ctrls.c +++ b/drivers/media/video/v4l2-ctrls.c @@ -604,6 +604,7 @@ const char *v4l2_ctrl_get_name(u32 id) case V4L2_CID_PRIVACY: return "Privacy"; case V4L2_CID_IRIS_ABSOLUTE: return "Iris, Absolute"; case V4L2_CID_IRIS_RELATIVE: return "Iris, Relative"; + case V4L2_CID_AUTO_EXPOSURE_BIAS: return "Auto Exposure, Bias"; /* FM Radio Modulator control */ /* Keep the order of the 'case's the same as in videodev2.h! */ @@ -760,6 +761,9 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type, case V4L2_CID_RDS_TX_RADIO_TEXT: *type = V4L2_CTRL_TYPE_STRING; break; + case V4L2_CID_AUTO_EXPOSURE_BIAS: + *type = V4L2_CTRL_TYPE_INTEGER_MENU; + break; case V4L2_CID_USER_CLASS: case V4L2_CID_CAMERA_CLASS: case V4L2_CID_MPEG_CLASS: diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h index 07bce86f3548..dfd209816df6 100644 --- a/include/linux/videodev2.h +++ b/include/linux/videodev2.h @@ -1707,6 +1707,8 @@ enum v4l2_exposure_auto_type { #define V4L2_CID_IRIS_ABSOLUTE (V4L2_CID_CAMERA_CLASS_BASE+17) #define V4L2_CID_IRIS_RELATIVE (V4L2_CID_CAMERA_CLASS_BASE+18) +#define V4L2_CID_AUTO_EXPOSURE_BIAS (V4L2_CID_CAMERA_CLASS_BASE+19) + /* FM Modulator class control IDs */ #define V4L2_CID_FM_TX_CLASS_BASE (V4L2_CTRL_CLASS_FM_TX | 0x900) #define V4L2_CID_FM_TX_CLASS (V4L2_CTRL_CLASS_FM_TX | 1) -- 2.30.2