The V4L2_CID_3A_LOCK bitmask control allows applications to pause
or resume the automatic exposure, focus and wite balance adjustments.
It can be used, for example, to lock the 3A adjustments right before
a still image is captured, for pre-focus, etc.
The applications can control each of the algorithms independently,
through a corresponding control bit, if driver allows that.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
Documentation/DocBook/media/v4l/controls.xml | 39 ++++++++++++++++++++++++++
drivers/media/video/v4l2-ctrls.c | 2 ++
include/linux/videodev2.h | 5 ++++
3 files changed, 46 insertions(+)
diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml
index c0256a0..ccb1df9 100644
--- a/Documentation/DocBook/media/v4l/controls.xml
+++ b/Documentation/DocBook/media/v4l/controls.xml
@@ -3301,6 +3301,45 @@ lens-distortion correction.</entry>
</row>
<row><entry></entry></row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_3A_LOCK</constant></entry>
+ <entry>bitmask</entry>
+ </row>
+ <row>
+ <entry spanname="descr">This control locks or unlocks the automatic
+focus, exposure and white balance. The automatic adjustments can be paused
+independently by setting the corresponding lock bit to 1. The camera then retains
+the settings until the lock bit is cleared. The following lock bits are defined:
+</entry>
+ </row>
+ <row>
+ <entrytbl spanname="descr" cols="2">
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_LOCK_EXPOSURE</constant></entry>
+ <entry>Automatic exposure adjustments lock.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_LOCK_WHITE_BALANCE</constant></entry>
+ <entry>Automatic white balance adjustments lock.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_LOCK_FOCUS</constant></entry>
+ <entry>Automatic focus lock.</entry>
+ </row>
+ </tbody>
+ </entrytbl>
+ </row>
+ <row><entry spanname="descr">
+When a given algorithm is not enabled, drivers should ignore requests
+to lock it and should return no error. An example might be an application
+setting bit <constant>V4L2_LOCK_WHITE_BALANCE</constant> when the
+<constant>V4L2_CID_AUTO_WHITE_BALANCE</constant> control is set to
+<constant>FALSE</constant>. The value of this control may be changed
+by exposure, white balance or focus controls.</entry>
+ </row>
+ <row><entry></entry></row>
+
</tbody>
</tgroup>
</table>
diff --git a/drivers/media/video/v4l2-ctrls.c b/drivers/media/video/v4l2-ctrls.c
index 4758e61..877ce60 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -661,6 +661,7 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_ISO_SENSITIVITY_AUTO: return "ISO Sensitivity, Auto";
case V4L2_CID_EXPOSURE_METERING: return "Exposure, Metering Mode";
case V4L2_CID_SCENE_MODE: return "Scene Mode";
+ case V4L2_CID_3A_LOCK: return "3A Lock";
/* FM Radio Modulator control */
/* Keep the order of the 'case's the same as in videodev2.h! */
@@ -833,6 +834,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
break;
case V4L2_CID_FLASH_FAULT:
case V4L2_CID_JPEG_ACTIVE_MARKER:
+ case V4L2_CID_3A_LOCK:
*type = V4L2_CTRL_TYPE_BITMASK;
break;
case V4L2_CID_MIN_BUFFERS_FOR_CAPTURE:
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 6f1c5de..dae57ed 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -1751,6 +1751,11 @@ enum v4l2_scene_mode {
V4L2_SCENE_MODE_TEXT = 13,
};
+#define V4L2_CID_3A_LOCK (V4L2_CID_CAMERA_CLASS_BASE+27)
+#define V4L2_LOCK_EXPOSURE (1 << 0)
+#define V4L2_LOCK_WHITE_BALANCE (1 << 1)
+#define V4L2_LOCK_FOCUS (1 << 2)
+
/* 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)
--
1.7.10
--
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