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From:   Stanimir Varbanov <stanimir.varbanov@linaro.org>
To:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Ezequiel Garcia <ezequiel@collabora.com>,
        Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        Nicolas Dufresne <nicolas@ndufresne.ca>,
        Tomasz Figa <tfiga@chromium.org>,
        Stanimir Varbanov <stanimir.varbanov@linaro.org>
Subject: [PATCH] v4l2-ctrl: add control for thumnails
Date:   Tue, 26 May 2020 11:54:46 +0300
Message-Id: <20200526085446.30956-1-stanimir.varbanov@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add v4l2 control for decoder thumbnail.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
---
 Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 7 +++++++
 drivers/media/v4l2-core/v4l2-ctrls.c                      | 2 ++
 include/uapi/linux/v4l2-controls.h                        | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index d0d506a444b1..e838e410651b 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -3726,6 +3726,13 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
     disables generating SPS and PPS at every IDR. Setting it to one enables
     generating SPS and PPS at every IDR.
 
+``V4L2_CID_MPEG_VIDEO_DECODER_THUMBNAIL (button)``
+    Instructs the decoder to produce immediate output. The decoder should
+    consume first input buffer for progressive stream (or first two buffers
+    for interlace). Decoder should not allocate more output buffers that it
+    is required to consume one input frame. Usually the decoder input
+    buffers will contain only I/IDR frames but it is not mandatory.
+
 .. _v4l2-mpeg-hevc:
 
 ``V4L2_CID_MPEG_VIDEO_HEVC_SPS (struct)``
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index b188577db40f..cb2554404c63 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -991,6 +991,7 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_MPEG_VIDEO_HEVC_SLICE_PARAMS:		return "HEVC Slice Parameters";
 	case V4L2_CID_MPEG_VIDEO_HEVC_DECODE_MODE:		return "HEVC Decode Mode";
 	case V4L2_CID_MPEG_VIDEO_HEVC_START_CODE:		return "HEVC Start Code";
+	case V4L2_CID_MPEG_VIDEO_DECODER_THUMBNAIL:		return "Thumbnail generation";
 
 	/* CAMERA controls */
 	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
@@ -1234,6 +1235,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_AUTO_FOCUS_START:
 	case V4L2_CID_AUTO_FOCUS_STOP:
 	case V4L2_CID_DO_WHITE_BALANCE:
+	case V4L2_CID_MPEG_VIDEO_DECODER_THUMBNAIL:
 		*type = V4L2_CTRL_TYPE_BUTTON;
 		*flags |= V4L2_CTRL_FLAG_WRITE_ONLY |
 			  V4L2_CTRL_FLAG_EXECUTE_ON_WRITE;
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 62271418c1be..7e44a2779863 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -743,6 +743,8 @@ enum v4l2_cid_mpeg_video_hevc_size_of_length_field {
 #define V4L2_CID_MPEG_VIDEO_REF_NUMBER_FOR_PFRAMES	(V4L2_CID_MPEG_BASE + 643)
 #define V4L2_CID_MPEG_VIDEO_PREPEND_SPSPPS_TO_IDR	(V4L2_CID_MPEG_BASE + 644)
 
+#define V4L2_CID_MPEG_VIDEO_DECODER_THUMBNAIL		(V4L2_CID_MPEG_BASE + 645)
+
 /*  MPEG-class control IDs specific to the CX2341x driver as defined by V4L2 */
 #define V4L2_CID_MPEG_CX2341X_BASE				(V4L2_CTRL_CLASS_MPEG | 0x1000)
 #define V4L2_CID_MPEG_CX2341X_VIDEO_SPATIAL_FILTER_MODE		(V4L2_CID_MPEG_CX2341X_BASE+0)
-- 
2.17.1