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Subject[PATCH 1/1] v4l: Add camera voice coil lens control class, current control
Date
From: Sakari Ailus <sakari.ailus@iki.fi>

Add a V4L2 control class for voice coil lens driver devices. These are
simple devices that are used to move a camera lens from its resting
position.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
Hi Pavel,

I also don't think the FOCUS_ABSOLUTE controls is a really good one for
the voice coil lens current. I expect more voice coil lens controls
(linear vs. PWM mode, ringing compensation...) to be needed so I think
it's worth a new class.

Cc others, too...

Kind regards,
Sakari

Documentation/DocBook/media/v4l/controls.xml | 55 +++++++++++++++++++++++++++-
include/uapi/linux/v4l2-controls.h | 7 ++++
2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/Documentation/DocBook/media/v4l/controls.xml b/Documentation/DocBook/media/v4l/controls.xml
index e2e5484..aa7169c 100644
--- a/Documentation/DocBook/media/v4l/controls.xml
+++ b/Documentation/DocBook/media/v4l/controls.xml
@@ -5502,4 +5502,57 @@ receiving given frequency when that control is set. This is a read-only control.
</tgroup>
</table>
</section>
-</section>
+
+ <section id="voice-coil-controls">
+ <title>Voice Coil Control Reference</title>
+
+ <para>The Voice Coil class controls are used to control voice
+ coil lens devices. These are very simple devices that consist of
+ a voice coil, a spring and a lens. The current applied on a
+ voice coil is used to move the lens away from the resting
+ position which typically is (close to) infinity.</para>
+
+ <table pgwide="1" frame="none" id="voice-coil-control-id">
+ <title>Voice Coil Control IDs</title>
+
+ <tgroup cols="4">
+ <colspec colname="c1" colwidth="1*" />
+ <colspec colname="c2" colwidth="6*" />
+ <colspec colname="c3" colwidth="2*" />
+ <colspec colname="c4" colwidth="6*" />
+ <spanspec namest="c1" nameend="c2" spanname="id" />
+ <spanspec namest="c2" nameend="c4" spanname="descr" />
+ <thead>
+ <row>
+ <entry spanname="id" align="left">ID</entry>
+ <entry align="left">Type</entry>
+ </row><row rowsep="1"><entry spanname="descr" align="left">Description</entry>
+ </row>
+ </thead>
+ <tbody valign="top">
+ <row><entry></entry></row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_VOICE_COIL_CLASS</constant>&nbsp;</entry>
+ <entry>class</entry>
+ </row><row><entry spanname="descr">The Voice Coil class
+descriptor. Calling &VIDIOC-QUERYCTRL; for this control will return a
+description of this control class.</entry>
+ </row>
+ <row>
+ <entry spanname="id"><constant>V4L2_CID_VOICE_COIL_CURRENT</constant>&nbsp;</entry>
+ <entry>integer</entry>
+ </row><row><entry spanname="descr">Current applied on a
+ voice coil. The more current is applied, the more is the
+ position of the lens moved from its resting position. Do
+ note that there may be a ringing effect; the lens will
+ oscillate after changing the current applied unless the
+ device implements ringing compensation.
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ </section>
+
+ </section>
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index b6a357a..c6b1261 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -62,6 +62,7 @@
#define V4L2_CTRL_CLASS_FM_RX 0x00a10000 /* FM Receiver controls */
#define V4L2_CTRL_CLASS_RF_TUNER 0x00a20000 /* RF tuner controls */
#define V4L2_CTRL_CLASS_DETECT 0x00a30000 /* Detection controls */
+#define V4L2_CTRL_CLASS_VOICE_COIL 0x00a40000 /* Voice coil lens driver */

/* User-class control IDs */

@@ -974,4 +975,10 @@ enum v4l2_detect_md_mode {
#define V4L2_CID_DETECT_MD_THRESHOLD_GRID (V4L2_CID_DETECT_CLASS_BASE + 3)
#define V4L2_CID_DETECT_MD_REGION_GRID (V4L2_CID_DETECT_CLASS_BASE + 4)

+/* Voice coil lens driver control IDs defined by V4L2 */
+#define V4L2_CID_VOICE_COIL_CLASS_BASE (V4L2_CTRL_CLASS_VOICE_COIL | 0x900)
+#define V4L2_CID_VOICE_COIL_CLASS (V4L2_CTRL_CLASS_VOICE_COIL | 1)
+
+#define V4L2_CID_VOICE_COIL_CURRENT (V4L2_CID_VOICE_COIL_CLASS_BASE + 1)
+
#endif
--
2.1.4
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