Hi Jai On Thu, Jun 27, 2024 at 06:40:04PM GMT, Jai Luthra wrote: > Use get_frame_desc() to get the frame desc from the connected source, > and use the provided virtual channel instead of hardcoded one. > > get_frame_desc() works per stream, but as we don't support multiple > streams yet, we will just always use stream 0. If the source doesn't > support get_frame_desc(), fall back to the previous method of always > capturing virtual channel 0. > > Co-developed-by: Pratyush Yadav <p.yadav@xxxxxx> > Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx> > Signed-off-by: Jai Luthra <j-luthra@xxxxxx> > --- > .../media/platform/ti/j721e-csi2rx/j721e-csi2rx.c | 39 ++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > index b4b4bb69c88a..c0916ca1a6f8 100644 > --- a/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > +++ b/drivers/media/platform/ti/j721e-csi2rx/j721e-csi2rx.c > @@ -29,6 +29,7 @@ > #define SHIM_DMACNTX_EN BIT(31) > #define SHIM_DMACNTX_YUV422 GENMASK(27, 26) > #define SHIM_DMACNTX_SIZE GENMASK(21, 20) > +#define SHIM_DMACNTX_VC GENMASK(9, 6) > #define SHIM_DMACNTX_FMT GENMASK(5, 0) > #define SHIM_DMACNTX_YUV422_MODE_11 3 > #define SHIM_DMACNTX_SIZE_8 0 > @@ -105,6 +106,8 @@ struct ti_csi2rx_ctx { > struct media_pad pad; > u32 sequence; > u32 idx; > + u32 vc; > + u32 stream; > }; > > struct ti_csi2rx_dev { > @@ -571,6 +574,7 @@ static void ti_csi2rx_setup_shim(struct ti_csi2rx_ctx *ctx) > } > > reg |= FIELD_PREP(SHIM_DMACNTX_SIZE, fmt->size); > + reg |= FIELD_PREP(SHIM_DMACNTX_VC, ctx->vc); > > writel(reg, csi->shim + SHIM_DMACNTX(ctx->idx)); > > @@ -844,6 +848,33 @@ static void ti_csi2rx_buffer_queue(struct vb2_buffer *vb) > } > } > > +static int ti_csi2rx_get_vc(struct ti_csi2rx_ctx *ctx) > +{ > + struct ti_csi2rx_dev *csi = ctx->csi; > + struct v4l2_mbus_frame_desc fd; > + struct media_pad *pad; > + int ret, i; > + > + pad = media_entity_remote_pad_unique(&csi->subdev.entity, MEDIA_PAD_FL_SOURCE); > + if (!pad) > + return -ENODEV; > + > + ret = v4l2_subdev_call(csi->source, pad, get_frame_desc, pad->index, > + &fd); > + if (ret) > + return ret; Would it be better to fail at bound() time if the remote subdev doesn't support get_frame_desc ? you can use if (!v4l2_subdev_has_op(subdev, pad, get_frame_desc)) { > + > + if (fd.type != V4L2_MBUS_FRAME_DESC_TYPE_CSI2) > + return -EINVAL; > + > + for (i = 0; i < fd.num_entries; i++) { for (unsigned int i should num_entries be validated ? > + if (ctx->stream == fd.entry[i].stream) > + return fd.entry[i].bus.csi2.vc; > + } > + > + return -ENODEV; > +} > + > static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count) > { > struct ti_csi2rx_ctx *ctx = vb2_get_drv_priv(vq); > @@ -864,6 +895,14 @@ static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count) > if (ret) > goto err; > > + ret = ti_csi2rx_get_vc(ctx); > + if (ret == -ENOIOCTLCMD) > + ctx->vc = 0; Ah, so you fallback to 0 in case the subdev doesn't support get_frame_desc. I'm not sure what would be better here maybe wait for other's opinions as well. Personally I would fail earlier to make sure subdev drivers are forced to impement get_frame_desc > + else if (ret < 0) > + goto err; > + else > + ctx->vc = ret; > + > ti_csi2rx_setup_shim(ctx); > > ctx->sequence = 0; > > -- > 2.43.0 > >