drivers: media: cfe: Set the CSI-2 link frequency correctly

Use the sensor provided link frequency to set the DPHY timing parameters
on stream_on. This replaces the hard-coded 999 MHz value currently being
used. As a fallback, revert to the original 999 Mhz link frequency.

As a drive-by, fix a 80-character line formatting error.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>

diff --git a/drivers/media/platform/raspberrypi/rp1_cfe/cfe.c b/drivers/media/platform/raspberrypi/rp1_cfe/cfe.c
index 8c4c11c..3808dd1 100644 (file)
--- a/drivers/media/platform/raspberrypi/rp1_cfe/cfe.c
+++ b/drivers/media/platform/raspberrypi/rp1_cfe/cfe.c
@@ -780,7 +780,8 @@ static void cfe_start_channel(struct cfe_node *node)
                        __func__, node_desc[FE_OUT0].name,
                        cfe->fe_csi2_channel);
 
-               source_fmt = v4l2_subdev_get_pad_format(&cfe->csi2.sd, state, cfe->fe_csi2_channel);
+               source_fmt = v4l2_subdev_get_pad_format(&cfe->csi2.sd, state,
+                                                       cfe->fe_csi2_channel);
                fmt = find_format_by_code(source_fmt->code);
 
                width = source_fmt->width;
@@ -982,6 +983,59 @@ static void cfe_buffer_queue(struct vb2_buffer *vb)
        spin_unlock_irqrestore(&cfe->state_lock, flags);
 }
 
+static u64 sensor_link_frequency(struct cfe_device *cfe)
+{
+       struct v4l2_mbus_framefmt *source_fmt;
+       struct v4l2_subdev_state *state;
+       struct media_entity *entity;
+       struct v4l2_subdev *subdev;
+       const struct cfe_fmt *fmt;
+       struct media_pad *pad;
+       s64 link_freq;
+
+       state = v4l2_subdev_lock_and_get_active_state(&cfe->csi2.sd);
+       source_fmt = v4l2_subdev_get_pad_format(&cfe->csi2.sd, state, 0);
+       fmt = find_format_by_code(source_fmt->code);
+       v4l2_subdev_unlock_state(state);
+
+       /*
+        * Walk up the media graph to find either the sensor entity, or another
+        * entity that advertises the V4L2_CID_LINK_FREQ or V4L2_CID_PIXEL_RATE
+        * control through the subdev.
+        */
+       entity = &cfe->csi2.sd.entity;
+       while (1) {
+               pad = &entity->pads[0];
+               if (!(pad->flags & MEDIA_PAD_FL_SINK))
+                       goto err;
+
+               pad = media_pad_remote_pad_first(pad);
+               if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
+                       goto err;
+
+               entity = pad->entity;
+               subdev = media_entity_to_v4l2_subdev(entity);
+               if (entity->function == MEDIA_ENT_F_CAM_SENSOR ||
+                   v4l2_ctrl_find(subdev->ctrl_handler, V4L2_CID_LINK_FREQ) ||
+                   v4l2_ctrl_find(subdev->ctrl_handler, V4L2_CID_PIXEL_RATE))
+                       break;
+       }
+
+       link_freq = v4l2_get_link_freq(subdev->ctrl_handler, fmt->depth,
+                                      cfe->csi2.active_data_lanes * 2);
+       if (link_freq < 0)
+               goto err;
+
+       /* x2 for DDR. */
+       link_freq *= 2;
+       cfe_info("Using a link frequency of %lld Hz\n", link_freq);
+       return link_freq;
+
+err:
+       cfe_err("Unable to determine sensor link frequency, using 999 MHz\n");
+       return 999 * 1000000UL;
+}
+
 static int cfe_start_streaming(struct vb2_queue *vq, unsigned int count)
 {
        struct v4l2_mbus_config mbus_config = { 0 };
@@ -1049,10 +1103,11 @@ static int cfe_start_streaming(struct vb2_queue *vq, unsigned int count)
                goto err_disable_cfe;
        }
 
-       cfe_dbg("Starting sensor streaming\n");
-
+       cfe_dbg("Configuring CSI-2 block\n");
+       cfe->csi2.dphy.dphy_freq = sensor_link_frequency(cfe) / 1000000UL;
        csi2_open_rx(&cfe->csi2);
 
+       cfe_dbg("Starting sensor streaming\n");
        cfe->sequence = 0;
        ret = v4l2_subdev_call(cfe->sensor, video, s_stream, 1);
        if (ret < 0) {
@@ -1945,8 +2000,6 @@ static int of_cfe_connect_subdevs(struct cfe_device *cfe)
                }
        }
 
-       /* TODO: Get the frequency from devicetree */
-       cfe->csi2.dphy.dphy_freq = 999;
        cfe->csi2.dphy.num_lanes = ep.bus.mipi_csi2.num_data_lanes;
        cfe->csi2.bus_flags = ep.bus.mipi_csi2.flags;