Add V4L2_CID_WHITE_BALANCE_PRESET control to allow selecting predefined
white balance configurations where supported by a camera. The following
menu items are included:
- V4L2_WHITE_BALANCE_NONE,
- V4L2_WHITE_BALANCE_INCANDESCENT,
- V4L2_WHITE_BALANCE_FLUORESCENT,
- V4L2_WHITE_BALANCE_DAYLIGHT,
- V4L2_WHITE_BALANCE_CLOUDY,
- V4L2_WHITE_BALANCE_SHADE,
This is a manual white balance control, in addition to V4L2_CID_RED_BALANCE,
V4L2_CID_BLUE_BALANCE and V4L2_CID_WHITE_BALANCE_TEMPERATURE.
Signed-off-by: HeungJun Kim <riverful.kim@xxxxxxxxxxx>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
Documentation/DocBook/media/v4l/controls.xml | 63 ++++++++++++++++++++++++++
drivers/media/video/v4l2-ctrls.c | 14 ++++++
include/linux/videodev2.h | 10 ++++
3 files changed, 87 insertions(+)
diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml
index 16742c0..f8e1161 100644
--- a/Documentation/DocBook/media/v4l/controls.xml
+++ b/Documentation/DocBook/media/v4l/controls.xml
@@ -3081,6 +3081,69 @@ camera sensor on or off, or specify its strength. Such band-stop filters can
be used, for example, to filter out the fluorescent light component.</entry>
</row>
<row><entry></entry></row>
+
+ <row id="v4l2-white-balance-preset">
+ <entry spanname="id"><constant>V4L2_CID_WHITE_BALANCE_PRESET</constant> </entry>
+ <entry>enum v4l2_white_balance_preset</entry>
+ </row><row><entry spanname="descr">Sets a predefined white balance
+configuration. The presets determine color temperature of the light on a basis
+of which the camera performs white balance adjustments, in order to obtain most
+accurate color representation. This control has no effect when automatic white
+balance adjustments are enabled, i.e. <constant>V4L2_CID_AUTO_WHITE_BALANCE
+</constant> control is set to <constant>TRUE</constant> (1). The following white
+balance presets are listed in order of incresing color temperature.</entry>
+ </row>
+ <row>
+ <entrytbl spanname="descr" cols="2">
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_NONE</constant> </entry>
+ <entry>None of the presets is active, i.e. the white balance
+preset feature is disabled. It is useful when driver exposes other manual white
+balance controls, like <constant>V4L2_CID_RED_BALANCE</constant> and <constant>
+V4L2_CID_BLUE_BALANCE</constant>, that may render a configured preset invalid.
+</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_INCANDESCENT</constant> </entry>
+ <entry>White balance settings for incandescent (tungsten) lighting.
+It generally cools down the colors and corresponds approximately to 2500...3500 K
+color temperature range.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_FLUORESCENT</constant> </entry>
+ <entry>With this setting the camera will compensate for fluorescent
+lighting. It corresponds approximately to 4000...5000 K color temperature.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_DAYLIGHT</constant> </entry>
+ <entry>White balance settings for daylight (with clear sky).
+This corresponds approximately to 5000...6500 K color temperature.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_FLASH</constant> </entry>
+ <entry>With this setting the camera will compensate for the flash
+light. It slightly warms up the colors and corresponds roughly to 5000...5500 K
+color temperature.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_CLOUDY</constant> </entry>
+ <entry>White balance settings for moderately overcast sky.
+This option corresponds approximately to 6500...8000 K color temperature range
+an will make colors appear warmer than with the <constant>
+V4L2_WHITE_BALANCE_PRESET_DAYLIGHT</constant> preset.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_WHITE_BALANCE_PRESET_SHADE</constant> </entry>
+ <entry>White balance settings for shade or heavily overcast
+sky. It corresponds approximately to 9000...10000 K color temperature.
+</entry>
+ </row>
+ </tbody>
+ </entrytbl>
+ </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 65aa63c..6dbbe03 100644
--- a/drivers/media/video/v4l2-ctrls.c
+++ b/drivers/media/video/v4l2-ctrls.c
@@ -256,6 +256,15 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
"Vivid",
NULL
};
+ static const char * const white_balance_preset[] = {
+ "None",
+ "Incandescent",
+ "Fluorescent",
+ "Daylight",
+ "Cloudy",
+ "Shade",
+ NULL,
+ };
static const char * const tune_preemphasis[] = {
"No Preemphasis",
"50 useconds",
@@ -429,6 +438,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
return camera_auto_focus_distance;
case V4L2_CID_COLORFX:
return colorfx;
+ case V4L2_CID_WHITE_BALANCE_PRESET:
+ return white_balance_preset;
case V4L2_CID_TUNE_PREEMPHASIS:
return tune_preemphasis;
case V4L2_CID_FLASH_LED_MODE:
@@ -621,6 +632,8 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_AUTO_FOCUS_AREA: return "Auto Focus, Area";
case V4L2_CID_AUTO_FOCUS_FACE_PRIORITY: return "Auto Focus, Face Priority";
+ case V4L2_CID_WHITE_BALANCE_PRESET: return "White Balance, Preset";
+
/* FM Radio Modulator control */
/* Keep the order of the 'case's the same as in videodev2.h! */
case V4L2_CID_FM_TX_CLASS: return "FM Radio Modulator Controls";
@@ -754,6 +767,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
case V4L2_CID_AUTO_FOCUS_AREA:
case V4L2_CID_AUTO_FOCUS_DISTANCE:
case V4L2_CID_COLORFX:
+ case V4L2_CID_WHITE_BALANCE_PRESET:
case V4L2_CID_TUNE_PREEMPHASIS:
case V4L2_CID_FLASH_LED_MODE:
case V4L2_CID_FLASH_STROBE_SOURCE:
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 615d939..250ac9e 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -1718,6 +1718,16 @@ enum v4l2_auto_focus_area {
#define V4L2_CID_AUTO_FOCUS_FACE_PRIORITY (V4L2_CID_CAMERA_CLASS_BASE+24)
+#define V4L2_CID_WHITE_BALANCE_PRESET (V4L2_CID_CAMERA_CLASS_BASE+30)
+enum v4l2_white_balance_preset {
+ V4L2_WHITE_BALANCE_PRESET_NONE = 0,
+ V4L2_WHITE_BALANCE_PRESET_INCANDESCENT = 1,
+ V4L2_WHITE_BALANCE_PRESET_FLUORESCENT = 2,
+ V4L2_WHITE_BALANCE_PRESET_DAYLIGHT = 3,
+ V4L2_WHITE_BALANCE_PRESET_CLOUDY = 4,
+ V4L2_WHITE_BALANCE_PRESET_SHADE = 5,
+};
+
/* 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)
--
1.7.9.2
--
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