[media] V4L: Add an extended camera white balance control

This patch adds V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE control which is
an extended version of the V4L2_CID_AUTO_WHITE_BALANCE control,
including white balance presets. The following presets are defined:

 - V4L2_WHITE_BALANCE_INCANDESCENT,
 - V4L2_WHITE_BALANCE_FLUORESCENT,
 - V4L2_WHITE_BALANCE_FLUORESCENT_H,
 - V4L2_WHITE_BALANCE_HORIZON,
 - V4L2_WHITE_BALANCE_DAYLIGHT,
 - V4L2_WHITE_BALANCE_FLASH,
 - V4L2_WHITE_BALANCE_CLOUDY,
 - V4L2_WHITE_BALANCE_SHADE.
Signed-off-by: HeungJun Kim <riverful.kim@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/controls.xml

@@ -3022,6 +3022,76 @@ 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-auto-n-preset-white-balance">
+	    <entry spanname="id"><constant>V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE</constant>&nbsp;</entry>
+	    <entry>enum&nbsp;v4l2_auto_n_preset_white_balance</entry>
+	  </row><row><entry spanname="descr">Sets white balance to automatic,
+manual or a preset. The presets determine color temperature of the light as
+a hint to the camera for white balance adjustments resulting in most accurate
+color representation. The following white balance presets are listed in order
+of increasing color temperature.</entry>
+	  </row>
+	  <row>
+	    <entrytbl spanname="descr" cols="2">
+	      <tbody valign="top">
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_MANUAL</constant>&nbsp;</entry>
+		  <entry>Manual white balance.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_AUTO</constant>&nbsp;</entry>
+		  <entry>Automatic white balance adjustments.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_INCANDESCENT</constant>&nbsp;</entry>
+		  <entry>White balance setting 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_FLUORESCENT</constant>&nbsp;</entry>
+		  <entry>White balance preset for fluorescent lighting.
+It corresponds approximately to 4000...5000 K color temperature.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_FLUORESCENT_H</constant>&nbsp;</entry>
+		  <entry>With this setting the camera will compensate for
+fluorescent H lighting.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_HORIZON</constant>&nbsp;</entry>
+		  <entry>White balance setting for horizon daylight.
+It corresponds approximately to 5000 K color temperature.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_DAYLIGHT</constant>&nbsp;</entry>
+		  <entry>White balance preset for daylight (with clear sky).
+It corresponds approximately to 5000...6500 K color temperature.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_FLASH</constant>&nbsp;</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_CLOUDY</constant>&nbsp;</entry>
+		  <entry>White balance preset for moderately overcast sky.
+This option corresponds approximately to 6500...8000 K color temperature
+range.</entry>
+		</row>
+		<row>
+		  <entry><constant>V4L2_WHITE_BALANCE_SHADE</constant>&nbsp;</entry>
+		  <entry>White balance preset 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>

drivers/media/video/v4l2-ctrls.c

@@ -249,6 +249,19 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
 		"Set Cb/Cr",
 		NULL
 	};
+	static const char * const auto_n_preset_white_balance[] = {
+		"Manual",
+		"Auto",
+		"Incandescent",
+		"Fluorescent",
+		"Fluorescent H",
+		"Horizon",
+		"Daylight",
+		"Flash",
+		"Cloudy",
+		"Shade",
+		NULL,
+	};
 	static const char * const tune_preemphasis[] = {
 		"No Preemphasis",
 		"50 Microseconds",
@@ -418,6 +431,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
 		return camera_exposure_auto;
 	case V4L2_CID_COLORFX:
 		return colorfx;
+	case V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE:
+		return auto_n_preset_white_balance;
 	case V4L2_CID_TUNE_PREEMPHASIS:
 		return tune_preemphasis;
 	case V4L2_CID_FLASH_LED_MODE:
@@ -605,6 +620,7 @@ const char *v4l2_ctrl_get_name(u32 id)
 	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";
+	case V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE: return "White Balance, Auto & Preset";
 
 	/* FM Radio Modulator control */
 	/* Keep the order of the 'case's the same as in videodev2.h! */
@@ -739,6 +755,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_MPEG_STREAM_VBI_FMT:
 	case V4L2_CID_EXPOSURE_AUTO:
 	case V4L2_CID_COLORFX:
+	case V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE:
 	case V4L2_CID_TUNE_PREEMPHASIS:
 	case V4L2_CID_FLASH_LED_MODE:
 	case V4L2_CID_FLASH_STROBE_SOURCE:

include/linux/videodev2.h

@@ -1709,6 +1709,20 @@ enum  v4l2_exposure_auto_type {
 
 #define V4L2_CID_AUTO_EXPOSURE_BIAS		(V4L2_CID_CAMERA_CLASS_BASE+19)
 
+#define V4L2_CID_AUTO_N_PRESET_WHITE_BALANCE	(V4L2_CID_CAMERA_CLASS_BASE+20)
+enum v4l2_auto_n_preset_white_balance {
+	V4L2_WHITE_BALANCE_MANUAL		= 0,
+	V4L2_WHITE_BALANCE_AUTO			= 1,
+	V4L2_WHITE_BALANCE_INCANDESCENT		= 2,
+	V4L2_WHITE_BALANCE_FLUORESCENT		= 3,
+	V4L2_WHITE_BALANCE_FLUORESCENT_H	= 4,
+	V4L2_WHITE_BALANCE_HORIZON		= 5,
+	V4L2_WHITE_BALANCE_DAYLIGHT		= 6,
+	V4L2_WHITE_BALANCE_FLASH		= 7,
+	V4L2_WHITE_BALANCE_CLOUDY		= 8,
+	V4L2_WHITE_BALANCE_SHADE		= 9,
+};
+
 /* 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)