Add support of several sub-devices within pipeline instead
of a single one.
This allows to support a CSI-2 camera sensor connected
through a CSI-2 to parallel bridge.

Signed-off-by: Hugues Fruchet <hugues.fruc...@st.com>
---
 drivers/media/platform/stm32/stm32-dcmi.c | 207 +++++++++++++++++++++++++++---
 1 file changed, 189 insertions(+), 18 deletions(-)

diff --git a/drivers/media/platform/stm32/stm32-dcmi.c 
b/drivers/media/platform/stm32/stm32-dcmi.c
index 3a69783..144912f 100644
--- a/drivers/media/platform/stm32/stm32-dcmi.c
+++ b/drivers/media/platform/stm32/stm32-dcmi.c
@@ -173,6 +173,7 @@ struct stm32_dcmi {
 
        struct media_device             mdev;
        struct media_pad                vid_cap_pad;
+       struct media_pipeline           pipeline;
 };
 
 static inline struct stm32_dcmi *notifier_to_dcmi(struct v4l2_async_notifier 
*n)
@@ -584,6 +585,135 @@ static void dcmi_buf_queue(struct vb2_buffer *vb)
        spin_unlock_irq(&dcmi->irqlock);
 }
 
+static struct media_entity *dcmi_find_sensor(struct stm32_dcmi *dcmi)
+{
+       struct media_entity *entity = &dcmi->vdev->entity;
+       struct v4l2_subdev *subdev;
+       struct media_pad *pad;
+
+       /* Walk searching for entity having no sink */
+       while (1) {
+               pad = &entity->pads[0];
+
+               subdev = media_entity_to_v4l2_subdev(entity);
+
+               if (!(pad->flags & MEDIA_PAD_FL_SINK))
+                       break;
+
+               pad = media_entity_remote_pad(pad);
+               if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
+                       break;
+
+               entity = pad->entity;
+       }
+
+       return entity;
+}
+
+static int dcmi_pipeline_s_fmt(struct stm32_dcmi *dcmi,
+                              struct v4l2_subdev_pad_config *pad_cfg,
+                              struct v4l2_subdev_format *format)
+{
+       struct media_entity *entity = &dcmi->sensor->entity;
+       struct v4l2_subdev *subdev;
+       struct media_pad *sink_pad = NULL;
+       struct media_pad *src_pad = NULL;
+       struct media_pad *pad = NULL;
+       struct v4l2_subdev_format fmt = *format;
+       bool found = false;
+       int ret;
+
+       /*
+        * Starting from sensor subdevice, walk within
+        * pipeline and set format on each subdevice
+        */
+       while (1) {
+               unsigned int i;
+
+               /* Search if current entity has a source pad */
+               for (i = 0; i < entity->num_pads; i++) {
+                       pad = &entity->pads[i];
+                       if (pad->flags & MEDIA_PAD_FL_SOURCE) {
+                               src_pad = pad;
+                               found = true;
+                               break;
+                       }
+               }
+               if (!found)
+                       break;
+
+               subdev = media_entity_to_v4l2_subdev(entity);
+
+               /* Propagate format on sink pad if any, otherwise source pad */
+               if (sink_pad)
+                       pad = sink_pad;
+
+               dev_dbg(dcmi->dev, "%s[%d] pad format set to 0x%x %ux%u\n",
+                       subdev->name, pad->index, format->format.code,
+                       format->format.width, format->format.height);
+
+               fmt.pad = pad->index;
+               ret = v4l2_subdev_call(subdev, pad, set_fmt, pad_cfg, &fmt);
+               if (ret < 0)
+                       return ret;
+
+               /* Walk to next entity */
+               sink_pad = media_entity_remote_pad(src_pad);
+               if (!sink_pad || !is_media_entity_v4l2_subdev(sink_pad->entity))
+                       break;
+
+               entity = sink_pad->entity;
+       }
+       *format = fmt;
+
+       return 0;
+}
+
+static int dcmi_pipeline_s_stream(struct stm32_dcmi *dcmi, int state)
+{
+       struct media_entity *entity = &dcmi->vdev->entity;
+       struct v4l2_subdev *subdev;
+       struct media_pad *pad;
+       int ret;
+
+       /* Start/stop all entities within pipeline */
+       while (1) {
+               pad = &entity->pads[0];
+               if (!(pad->flags & MEDIA_PAD_FL_SINK))
+                       break;
+
+               pad = media_entity_remote_pad(pad);
+               if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
+                       break;
+
+               entity = pad->entity;
+               subdev = media_entity_to_v4l2_subdev(entity);
+
+               ret = v4l2_subdev_call(subdev, video, s_stream, state);
+               if (ret < 0 && ret != -ENOIOCTLCMD) {
+                       dev_err(dcmi->dev, "%s: %s failed to %s streaming 
(%d)\n",
+                               __func__, subdev->name,
+                               state ? "start" : "stop", ret);
+                       return ret;
+               }
+
+               dev_dbg(dcmi->dev, "%s is %s\n",
+                       subdev->name, state ? "started" : "stopped");
+       }
+
+       return 0;
+}
+
+static int dcmi_pipeline_start(struct stm32_dcmi *dcmi)
+{
+       return dcmi_pipeline_s_stream(dcmi, 1);
+}
+
+static void dcmi_pipeline_stop(struct stm32_dcmi *dcmi)
+{
+       dcmi_pipeline_s_stream(dcmi, 0);
+}
+
 static int dcmi_start_streaming(struct vb2_queue *vq, unsigned int count)
 {
        struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
@@ -598,14 +728,17 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
                goto err_release_buffers;
        }
 
-       /* Enable stream on the sub device */
-       ret = v4l2_subdev_call(dcmi->sensor, video, s_stream, 1);
-       if (ret && ret != -ENOIOCTLCMD) {
-               dev_err(dcmi->dev, "%s: Failed to start streaming, subdev 
streamon error",
-                       __func__);
+       ret = media_pipeline_start(&dcmi->vdev->entity, &dcmi->pipeline);
+       if (ret < 0) {
+               dev_err(dcmi->dev, "%s: Failed to start streaming, media 
pipeline start error (%d)\n",
+                       __func__, ret);
                goto err_pm_put;
        }
 
+       ret = dcmi_pipeline_start(dcmi);
+       if (ret)
+               goto err_media_pipeline_stop;
+
        spin_lock_irq(&dcmi->irqlock);
 
        /* Set bus width */
@@ -677,7 +810,7 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
        if (ret) {
                dev_err(dcmi->dev, "%s: Start streaming failed, cannot start 
capture\n",
                        __func__);
-               goto err_subdev_streamoff;
+               goto err_pipeline_stop;
        }
 
        /* Enable interruptions */
@@ -688,8 +821,11 @@ static int dcmi_start_streaming(struct vb2_queue *vq, 
unsigned int count)
 
        return 0;
 
-err_subdev_streamoff:
-       v4l2_subdev_call(dcmi->sensor, video, s_stream, 0);
+err_pipeline_stop:
+       dcmi_pipeline_stop(dcmi);
+
+err_media_pipeline_stop:
+       media_pipeline_stop(&dcmi->vdev->entity);
 
 err_pm_put:
        pm_runtime_put(dcmi->dev);
@@ -714,13 +850,10 @@ static void dcmi_stop_streaming(struct vb2_queue *vq)
 {
        struct stm32_dcmi *dcmi = vb2_get_drv_priv(vq);
        struct dcmi_buf *buf, *node;
-       int ret;
 
-       /* Disable stream on the sub device */
-       ret = v4l2_subdev_call(dcmi->sensor, video, s_stream, 0);
-       if (ret && ret != -ENOIOCTLCMD)
-               dev_err(dcmi->dev, "%s: Failed to stop streaming, subdev 
streamoff error (%d)\n",
-                       __func__, ret);
+       dcmi_pipeline_stop(dcmi);
+
+       media_pipeline_stop(&dcmi->vdev->entity);
 
        spin_lock_irq(&dcmi->irqlock);
 
@@ -938,8 +1071,7 @@ static int dcmi_set_fmt(struct stm32_dcmi *dcmi, struct 
v4l2_format *f)
        mf->width = sd_framesize.width;
        mf->height = sd_framesize.height;
 
-       ret = v4l2_subdev_call(dcmi->sensor, pad,
-                              set_fmt, NULL, &format);
+       ret = dcmi_pipeline_s_fmt(dcmi, NULL, &format);
        if (ret < 0)
                return ret;
 
@@ -1530,7 +1662,19 @@ static int dcmi_graph_notify_complete(struct 
v4l2_async_notifier *notifier)
        struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
        int ret;
 
+       /*
+        * Now that the graph is complete,
+        * we search for the camera sensor subdevice
+        * in order to expose it through V4L2 interface
+        */
+       dcmi->sensor = media_entity_to_v4l2_subdev(dcmi_find_sensor(dcmi));
+       if (!dcmi->sensor) {
+               dev_err(dcmi->dev, "No camera sensor subdevice found\n");
+               return -ENODEV;
+       }
+
        dcmi->vdev->ctrl_handler = dcmi->sensor->ctrl_handler;
+
        ret = dcmi_formats_init(dcmi);
        if (ret) {
                dev_err(dcmi->dev, "No supported mediabus format found\n");
@@ -1574,12 +1718,30 @@ static int dcmi_graph_notify_bound(struct 
v4l2_async_notifier *notifier,
                                   struct v4l2_async_subdev *asd)
 {
        struct stm32_dcmi *dcmi = notifier_to_dcmi(notifier);
+       unsigned int ret;
+       int src_pad;
 
        dev_dbg(dcmi->dev, "Subdev %s bound\n", subdev->name);
 
-       dcmi->sensor = subdev;
+       /*
+        * Link this sub-device to DCMI, it could be
+        * a parallel camera sensor or a bridge
+        */
+       src_pad = media_entity_get_fwnode_pad(&subdev->entity,
+                                             subdev->fwnode,
+                                             MEDIA_PAD_FL_SOURCE);
+
+       ret = media_create_pad_link(&subdev->entity, src_pad,
+                                   &dcmi->vdev->entity, 0,
+                                   MEDIA_LNK_FL_IMMUTABLE |
+                                   MEDIA_LNK_FL_ENABLED);
+       if (ret)
+               dev_err(dcmi->dev, "Failed to create media pad link with subdev 
%s\n",
+                       subdev->name);
+       else
+               dev_dbg(dcmi->dev, "DCMI is now linked to %s\n", subdev->name);
 
-       return 0;
+       return ret;
 }
 
 static const struct v4l2_async_notifier_operations dcmi_graph_notify_ops = {
@@ -1639,6 +1801,15 @@ static int dcmi_graph_init(struct stm32_dcmi *dcmi)
                return ret;
        }
 
+       /* Register all the subdev nodes */
+       ret = v4l2_device_register_subdev_nodes(&dcmi->v4l2_dev);
+       if (ret) {
+               dev_err(dcmi->dev, "Failed to register subdev nodes\n");
+               v4l2_async_notifier_unregister(&dcmi->notifier);
+               of_node_put(dcmi->entity.node);
+               return ret;
+       }
+
        return 0;
 }
 
-- 
2.7.4

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