Hi Márton,
On Sunday 28 February 2010 08:55:04 Németh Márton wrote:
> From: Márton Németh <nm127@xxxxxxxxxxx>
>
> On some webcams a feedback LED can be found. This LED usually shows
> the state of streaming mode: this is the "Auto" mode. The LED can
> be programmed to constantly switched off state (e.g. for power saving
> reasons, preview mode) or on state (e.g. the application shows motion
> detection or "on-air").
>
> Signed-off-by: Márton Németh <nm127@xxxxxxxxxxx>
> ---
> diff -r d8fafa7d88dc linux/Documentation/DocBook/v4l/controls.xml
> --- a/linux/Documentation/DocBook/v4l/controls.xml Thu Feb 18 19:02:51
2010
> +0100 +++ b/linux/Documentation/DocBook/v4l/controls.xml Sun Feb 28
> 08:41:17 2010 +0100 @@ -311,6 +311,17 @@
> Applications depending on particular custom controls should check the
> driver name and version, see <xref linkend="querycap" />.</entry>
> </row>
> + <row id="v4l2-led">
> + <entry><constant>V4L2_CID_LED</constant></entry>
> + <entry>enum</entry>
> + <entry>Controls the feedback LED on the camera. In auto mode
> +the LED is on when the streaming is active. The LED is off when not
> streaming. +The LED can be also turned on and off independent from
> streaming. +Possible values for <constant>enum v4l2_led</constant> are:
> +<constant>V4L2_CID_LED_AUTO</constant> (0),
> +<constant>V4L2_CID_LED_ON</constant> (1) and
> +<constant>V4L2_CID_LED_OFF</constant> (2).</entry>
> + </row>
There's more than just auto, on and off. On Logitech webcams, LEDs can be
configured to blink as well.
> </tbody>
> </tgroup>
> </table>
> diff -r d8fafa7d88dc linux/Documentation/DocBook/v4l/videodev2.h.xml
> --- a/linux/Documentation/DocBook/v4l/videodev2.h.xml Thu Feb 18 19:02:51
> 2010 +0100 +++ b/linux/Documentation/DocBook/v4l/videodev2.h.xml Sun Feb
> 28 08:41:17 2010 +0100 @@ -1024,8 +1024,14 @@
>
> #define V4L2_CID_ROTATE (V4L2_CID_BASE+34)
> #define V4L2_CID_BG_COLOR (V4L2_CID_BASE+35)
> +#define V4L2_CID_LED (V4L2_CID_BASE+36)
> +enum v4l2_led {
> + V4L2_LED_AUTO = 0,
> + V4L2_LED_ON = 1,
> + V4L2_LED_OFF = 2,
> +};
> /* last CID + 1 */
> -#define V4L2_CID_LASTP1 (V4L2_CID_BASE+36)
> +#define V4L2_CID_LASTP1 (V4L2_CID_BASE+37)
>
> /* MPEG-class control IDs defined by V4L2 */
> #define V4L2_CID_MPEG_BASE (V4L2_CTRL_CLASS_MPEG |
> 0x900) diff -r d8fafa7d88dc linux/drivers/media/video/v4l2-common.c
> --- a/linux/drivers/media/video/v4l2-common.c Thu Feb 18 19:02:51 2010
> +0100 +++ b/linux/drivers/media/video/v4l2-common.c Sun Feb 28 08:41:17
> 2010 +0100 @@ -349,6 +349,12 @@
> "75 useconds",
> NULL,
> };
> + static const char *led[] = {
> + "Auto",
> + "On",
> + "Off",
> + NULL,
> + };
>
> switch (id) {
> case V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ:
> @@ -389,6 +395,8 @@
> return colorfx;
> case V4L2_CID_TUNE_PREEMPHASIS:
> return tune_preemphasis;
> + case V4L2_CID_LED:
> + return led;
> default:
> return NULL;
> }
> @@ -434,6 +442,7 @@
> case V4L2_CID_COLORFX: return "Color Effects";
> case V4L2_CID_ROTATE: return "Rotate";
> case V4L2_CID_BG_COLOR: return "Background color";
> + case V4L2_CID_LED: return "Feedback LED";
>
> /* MPEG controls */
> case V4L2_CID_MPEG_CLASS: return "MPEG Encoder Controls";
> @@ -575,6 +584,7 @@
> case V4L2_CID_EXPOSURE_AUTO:
> case V4L2_CID_COLORFX:
> case V4L2_CID_TUNE_PREEMPHASIS:
> + case V4L2_CID_LED:
> qctrl->type = V4L2_CTRL_TYPE_MENU;
> step = 1;
> break;
> diff -r d8fafa7d88dc linux/include/linux/videodev2.h
> --- a/linux/include/linux/videodev2.h Thu Feb 18 19:02:51 2010 +0100
> +++ b/linux/include/linux/videodev2.h Sun Feb 28 08:41:17 2010 +0100
> @@ -1030,8 +1030,14 @@
>
> #define V4L2_CID_ROTATE (V4L2_CID_BASE+34)
> #define V4L2_CID_BG_COLOR (V4L2_CID_BASE+35)
> +#define V4L2_CID_LED (V4L2_CID_BASE+36)
> +enum v4l2_led {
> + V4L2_LED_AUTO = 0,
> + V4L2_LED_ON = 1,
> + V4L2_LED_OFF = 2,
> +};
enums shouldn't be used in kernelspace <-> userspace APIs, as their size is
not stable across ARM ABIs. In this case it won't matter much, the enum not
being part of any structure. If someone creates a new ioctl that uses enum
v4l2_led as one field of its structure argument, things will break.
> /* last CID + 1 */
> -#define V4L2_CID_LASTP1 (V4L2_CID_BASE+36)
> +#define V4L2_CID_LASTP1 (V4L2_CID_BASE+37)
>
> /* MPEG-class control IDs defined by V4L2 */
> #define V4L2_CID_MPEG_BASE (V4L2_CTRL_CLASS_MPEG | 0x900)
--
Regards,
Laurent Pinchart
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