media: v4l2-dev/ioctl: Add V4L2_CAP_IO_MC

Add a video device capability flag to indicate that its inputs and/or
outputs are controlled by the Media Controller instead of the V4L2 API.
When this flag is set, ioctl for enum inputs and outputs are
automatically enabled and programmed to call a helper function.
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/userspace-api/media/v4l/vidioc-querycap.rst

@@ -264,6 +264,12 @@ specification the ioctl returns an ``EINVAL`` error code.
     * - ``V4L2_CAP_TOUCH``
       - 0x10000000
       - This is a touch device.
+    * - ``V4L2_CAP_IO_MC``
+      - 0x20000000
+      - There is only one input and/or output seen from userspace. The whole
+        video topology configuration, including which I/O entity is routed to
+        the input/output, is configured by userspace via the Media Controller.
+        See :ref:`media_controller`.
     * - ``V4L2_CAP_DEVICE_CAPS``
       - 0x80000000
       - The driver fills the ``device_caps`` field. This capability can

Documentation/userspace-api/media/videodev2.h.rst.exceptions

@@ -176,6 +176,7 @@ replace define V4L2_CAP_STREAMING device-capabilities
 replace define V4L2_CAP_META_OUTPUT device-capabilities
 replace define V4L2_CAP_DEVICE_CAPS device-capabilities
 replace define V4L2_CAP_TOUCH device-capabilities
+replace define V4L2_CAP_IO_MC device-capabilities
 
 # V4L2 pix flags
 replace define V4L2_PIX_FMT_PRIV_MAGIC :c:type:`v4l2_pix_format`

drivers/media/v4l2-core/v4l2-dev.c

@@ -552,6 +552,7 @@ static void determine_valid_ioctls(struct video_device *vdev)
 		       (vdev->device_caps & meta_caps);
 	bool is_rx = vdev->vfl_dir != VFL_DIR_TX;
 	bool is_tx = vdev->vfl_dir != VFL_DIR_RX;
+	bool is_io_mc = vdev->device_caps & V4L2_CAP_IO_MC;
 
 	bitmap_zero(valid_ioctls, BASE_VIDIOC_PRIVATE);
 
@@ -725,9 +726,15 @@ static void determine_valid_ioctls(struct video_device *vdev)
 		SET_VALID_IOCTL(ops, VIDIOC_G_STD, vidioc_g_std);
 		if (is_rx) {
 			SET_VALID_IOCTL(ops, VIDIOC_QUERYSTD, vidioc_querystd);
+			if (is_io_mc) {
+				set_bit(_IOC_NR(VIDIOC_ENUMINPUT), valid_ioctls);
+				set_bit(_IOC_NR(VIDIOC_G_INPUT), valid_ioctls);
+				set_bit(_IOC_NR(VIDIOC_S_INPUT), valid_ioctls);
+			} else {
 				SET_VALID_IOCTL(ops, VIDIOC_ENUMINPUT, vidioc_enum_input);
 				SET_VALID_IOCTL(ops, VIDIOC_G_INPUT, vidioc_g_input);
 				SET_VALID_IOCTL(ops, VIDIOC_S_INPUT, vidioc_s_input);
+			}
 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDIO, vidioc_enumaudio);
 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDIO, vidioc_g_audio);
 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDIO, vidioc_s_audio);
@@ -735,9 +742,15 @@ static void determine_valid_ioctls(struct video_device *vdev)
 			SET_VALID_IOCTL(ops, VIDIOC_S_EDID, vidioc_s_edid);
 		}
 		if (is_tx) {
+			if (is_io_mc) {
+				set_bit(_IOC_NR(VIDIOC_ENUMOUTPUT), valid_ioctls);
+				set_bit(_IOC_NR(VIDIOC_G_OUTPUT), valid_ioctls);
+				set_bit(_IOC_NR(VIDIOC_S_OUTPUT), valid_ioctls);
+			} else {
 				SET_VALID_IOCTL(ops, VIDIOC_ENUMOUTPUT, vidioc_enum_output);
 				SET_VALID_IOCTL(ops, VIDIOC_G_OUTPUT, vidioc_g_output);
 				SET_VALID_IOCTL(ops, VIDIOC_S_OUTPUT, vidioc_s_output);
+			}
 			SET_VALID_IOCTL(ops, VIDIOC_ENUMAUDOUT, vidioc_enumaudout);
 			SET_VALID_IOCTL(ops, VIDIOC_G_AUDOUT, vidioc_g_audout);
 			SET_VALID_IOCTL(ops, VIDIOC_S_AUDOUT, vidioc_s_audout);

drivers/media/v4l2-core/v4l2-ioctl.c

@@ -1085,6 +1085,32 @@ static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
 	return ret;
 }
 
+static int v4l_g_input(const struct v4l2_ioctl_ops *ops,
+		       struct file *file, void *fh, void *arg)
+{
+	struct video_device *vfd = video_devdata(file);
+
+	if (vfd->device_caps & V4L2_CAP_IO_MC) {
+		*(int *)arg = 0;
+		return 0;
+	}
+
+	return ops->vidioc_g_input(file, fh, arg);
+}
+
+static int v4l_g_output(const struct v4l2_ioctl_ops *ops,
+			struct file *file, void *fh, void *arg)
+{
+	struct video_device *vfd = video_devdata(file);
+
+	if (vfd->device_caps & V4L2_CAP_IO_MC) {
+		*(int *)arg = 0;
+		return 0;
+	}
+
+	return ops->vidioc_g_output(file, fh, arg);
+}
+
 static int v4l_s_input(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
@@ -1094,12 +1120,21 @@ static int v4l_s_input(const struct v4l2_ioctl_ops *ops,
 	ret = v4l_enable_media_source(vfd);
 	if (ret)
 		return ret;
+
+	if (vfd->device_caps & V4L2_CAP_IO_MC)
+		return  *(int *)arg ? -EINVAL : 0;
+
 	return ops->vidioc_s_input(file, fh, *(unsigned int *)arg);
 }
 
 static int v4l_s_output(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
+	struct video_device *vfd = video_devdata(file);
+
+	if (vfd->device_caps & V4L2_CAP_IO_MC)
+		return  *(int *)arg ? -EINVAL : 0;
+
 	return ops->vidioc_s_output(file, fh, *(unsigned int *)arg);
 }
 
@@ -1143,6 +1178,14 @@ static int v4l_enuminput(const struct v4l2_ioctl_ops *ops,
 	if (is_valid_ioctl(vfd, VIDIOC_S_STD))
 		p->capabilities |= V4L2_IN_CAP_STD;
 
+	if (vfd->device_caps & V4L2_CAP_IO_MC) {
+		if (p->index)
+			return -EINVAL;
+		strscpy(p->name, vfd->name, sizeof(p->name));
+		p->type = V4L2_INPUT_TYPE_CAMERA;
+		return 0;
+	}
+
 	return ops->vidioc_enum_input(file, fh, p);
 }
 
@@ -1161,6 +1204,14 @@ static int v4l_enumoutput(const struct v4l2_ioctl_ops *ops,
 	if (is_valid_ioctl(vfd, VIDIOC_S_STD))
 		p->capabilities |= V4L2_OUT_CAP_STD;
 
+	if (vfd->device_caps & V4L2_CAP_IO_MC) {
+		if (p->index)
+			return -EINVAL;
+		strscpy(p->name, vfd->name, sizeof(p->name));
+		p->type = V4L2_OUTPUT_TYPE_ANALOG;
+		return 0;
+	}
+
 	return ops->vidioc_enum_output(file, fh, p);
 }
 
@@ -2683,10 +2734,8 @@ DEFINE_V4L_STUB_FUNC(expbuf)
 DEFINE_V4L_STUB_FUNC(g_std)
 DEFINE_V4L_STUB_FUNC(g_audio)
 DEFINE_V4L_STUB_FUNC(s_audio)
-DEFINE_V4L_STUB_FUNC(g_input)
 DEFINE_V4L_STUB_FUNC(g_edid)
 DEFINE_V4L_STUB_FUNC(s_edid)
-DEFINE_V4L_STUB_FUNC(g_output)
 DEFINE_V4L_STUB_FUNC(g_audout)
 DEFINE_V4L_STUB_FUNC(s_audout)
 DEFINE_V4L_STUB_FUNC(g_jpegcomp)
@@ -2735,11 +2784,11 @@ static const struct v4l2_ioctl_info v4l2_ioctls[] = {
 	IOCTL_INFO(VIDIOC_S_AUDIO, v4l_stub_s_audio, v4l_print_audio, INFO_FL_PRIO),
 	IOCTL_INFO(VIDIOC_QUERYCTRL, v4l_queryctrl, v4l_print_queryctrl, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_queryctrl, id)),
 	IOCTL_INFO(VIDIOC_QUERYMENU, v4l_querymenu, v4l_print_querymenu, INFO_FL_CTRL | INFO_FL_CLEAR(v4l2_querymenu, index)),
-	IOCTL_INFO(VIDIOC_G_INPUT, v4l_stub_g_input, v4l_print_u32, 0),
+	IOCTL_INFO(VIDIOC_G_INPUT, v4l_g_input, v4l_print_u32, 0),
 	IOCTL_INFO(VIDIOC_S_INPUT, v4l_s_input, v4l_print_u32, INFO_FL_PRIO),
 	IOCTL_INFO(VIDIOC_G_EDID, v4l_stub_g_edid, v4l_print_edid, INFO_FL_ALWAYS_COPY),
 	IOCTL_INFO(VIDIOC_S_EDID, v4l_stub_s_edid, v4l_print_edid, INFO_FL_PRIO | INFO_FL_ALWAYS_COPY),
-	IOCTL_INFO(VIDIOC_G_OUTPUT, v4l_stub_g_output, v4l_print_u32, 0),
+	IOCTL_INFO(VIDIOC_G_OUTPUT, v4l_g_output, v4l_print_u32, 0),
 	IOCTL_INFO(VIDIOC_S_OUTPUT, v4l_s_output, v4l_print_u32, INFO_FL_PRIO),
 	IOCTL_INFO(VIDIOC_ENUMOUTPUT, v4l_enumoutput, v4l_print_enumoutput, INFO_FL_CLEAR(v4l2_output, index)),
 	IOCTL_INFO(VIDIOC_G_AUDOUT, v4l_stub_g_audout, v4l_print_audioout, 0),

include/uapi/linux/videodev2.h

@@ -487,6 +487,8 @@ struct v4l2_capability {
 
 #define V4L2_CAP_TOUCH                  0x10000000  /* Is a touch device */
 
+#define V4L2_CAP_IO_MC			0x20000000  /* Is input/output controlled by the media controller */
+
 #define V4L2_CAP_DEVICE_CAPS            0x80000000  /* sets device capabilities field */
 
 /*