media: qcom: camss: Power pipeline only when streaming

The libcamera plugin for Pipewire may keep an open file descriptor to
the video device, even while streaming. This simplifies its operation,
as it only needs to keep track of a number instead of a file path. When
the video device is open but not streaming, the pipeline can be powered
off. Move the pipeline power management to the prepare_streaming and
unprepare_streaming functions.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Signed-off-by: Bryan O'Donoghue <bod@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/drivers/media/platform/qcom/camss/camss-video.c b/drivers/media/platform/qcom/camss/camss-video.c
index aa021fd5e1233ba413acc9fdbac6b677619079b4..8d05802d1735a35cb1a1a0a81c6666b1517dd2e6 100644 (file)
--- a/drivers/media/platform/qcom/camss/camss-video.c
+++ b/drivers/media/platform/qcom/camss/camss-video.c
@@ -225,6 +225,21 @@ static int video_check_format(struct camss_video *video)
        return 0;
 }
 
+static int video_prepare_streaming(struct vb2_queue *q)
+{
+       struct camss_video *video = vb2_get_drv_priv(q);
+       struct video_device *vdev = &video->vdev;
+       int ret;
+
+       ret = v4l2_pipeline_pm_get(&vdev->entity);
+       if (ret < 0) {
+               dev_err(video->camss->dev, "Failed to power up pipeline: %d\n",
+                       ret);
+       }
+
+       return ret;
+}
+
 static int video_start_streaming(struct vb2_queue *q, unsigned int count)
 {
        struct camss_video *video = vb2_get_drv_priv(q);
@@ -308,13 +323,23 @@ static void video_stop_streaming(struct vb2_queue *q)
        video->ops->flush_buffers(video, VB2_BUF_STATE_ERROR);
 }
 
+static void video_unprepare_streaming(struct vb2_queue *q)
+{
+       struct camss_video *video = vb2_get_drv_priv(q);
+       struct video_device *vdev = &video->vdev;
+
+       v4l2_pipeline_pm_put(&vdev->entity);
+}
+
 static const struct vb2_ops msm_video_vb2_q_ops = {
        .queue_setup     = video_queue_setup,
        .buf_init        = video_buf_init,
        .buf_prepare     = video_buf_prepare,
        .buf_queue       = video_buf_queue,
+       .prepare_streaming = video_prepare_streaming,
        .start_streaming = video_start_streaming,
        .stop_streaming  = video_stop_streaming,
+       .unprepare_streaming = video_unprepare_streaming,
 };
 
 /* -----------------------------------------------------------------------------
@@ -599,20 +624,10 @@ static int video_open(struct file *file)
 
        file->private_data = vfh;
 
-       ret = v4l2_pipeline_pm_get(&vdev->entity);
-       if (ret < 0) {
-               dev_err(video->camss->dev, "Failed to power up pipeline: %d\n",
-                       ret);
-               goto error_pm_use;
-       }
-
        mutex_unlock(&video->lock);
 
        return 0;
 
-error_pm_use:
-       v4l2_fh_release(file);
-
 error_alloc:
        mutex_unlock(&video->lock);
 
@@ -621,12 +636,8 @@ error_alloc:
 
 static int video_release(struct file *file)
 {
-       struct video_device *vdev = video_devdata(file);
-
        vb2_fop_release(file);
 
-       v4l2_pipeline_pm_put(&vdev->entity);
-
        file->private_data = NULL;
 
        return 0;