Re: [PATCH 2/5] media: synopsys: Add support for multiple streams

[Frank Li]

On Wed, Apr 15, 2026 at 11:46:53AM +0800, Guoniu Zhou wrote:
> The current driver only supports single stream operation. Add support
> for multiple concurrent streams by tracking enabled streams with a
> bitmask and only initializing the hardware once for the first stream.
>
> This enables use cases such as surround view systems where multiple
> camera streams need to be processed simultaneously through the same
> CSI-2 receiver interface.
>
> Signed-off-by: Guoniu Zhou <guoniu.zhou@xxxxxxxxxxx>
> ---
>  drivers/media/platform/synopsys/dw-mipi-csi2rx.c | 45 ++++++++++++++----------
>  1 file changed, 27 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> index 46e2a4315ac2..85a2a95bf080 100644
> --- a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> +++ b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> @@ -113,6 +113,7 @@ struct dw_mipi_csi2rx_device {
>
>  	enum v4l2_mbus_type bus_type;
>  	u32 lanes_num;
> +	u64 enabled_streams;
>
>  	const struct dw_mipi_csi2rx_drvdata *drvdata;
>  };
> @@ -528,28 +529,31 @@ static int dw_mipi_csi2rx_enable_streams(struct v4l2_subdev *sd,
>  					       DW_MIPI_CSI2RX_PAD_SRC,
>  					       &streams_mask);
>

It maybe simpler

	u64 enabled_streams = csi2->enabled_streams;

	csi2->enabled_streams |= streams_mask;

	if (!enabled_stream)
		return 0;


....

err:
	si2->enabled_streams &= ~streams_mask;


Frank

> -	ret = pm_runtime_resume_and_get(dev);
> -	if (ret)
> -		goto err;
> +	if (!csi2->enabled_streams) {
> +		ret = pm_runtime_resume_and_get(dev);
> +		if (ret)
> +			return ret;
>
> -	ret = dw_mipi_csi2rx_start(csi2);
> -	if (ret) {
> -		dev_err(dev, "failed to enable CSI hardware\n");
> -		goto err_pm_runtime_put;
> +		ret = dw_mipi_csi2rx_start(csi2);
> +		if (ret) {
> +			pm_runtime_put(dev);
> +			dev_err(dev, "failed to enable CSI hardware\n");
> +			return ret;
> +		}
>  	}
>
>  	ret = v4l2_subdev_enable_streams(remote_sd, remote_pad->index, mask);
> -	if (ret)
> -		goto err_csi_stop;
> +	if (ret) {
> +		if (!csi2->enabled_streams) {
> +			dw_mipi_csi2rx_stop(csi2);
> +			pm_runtime_put(dev);
> +		}
> +		return ret;
> +	}
>
> -	return 0;
> +	csi2->enabled_streams |= streams_mask;
>
> -err_csi_stop:
> -	dw_mipi_csi2rx_stop(csi2);
> -err_pm_runtime_put:
> -	pm_runtime_put(dev);
> -err:
> -	return ret;
> +	return 0;
>  }
>
>  static int dw_mipi_csi2rx_disable_streams(struct v4l2_subdev *sd,
> @@ -572,10 +576,15 @@ static int dw_mipi_csi2rx_disable_streams(struct v4l2_subdev *sd,
>  					       &streams_mask);
>
>  	ret = v4l2_subdev_disable_streams(remote_sd, remote_pad->index, mask);
> +	if (ret)
> +		dev_err(dev, "failed to disable streams on remote subdev: %d\n", ret);
>
> -	dw_mipi_csi2rx_stop(csi2);
> +	csi2->enabled_streams &= ~streams_mask;
>
> -	pm_runtime_put(dev);
> +	if (!csi2->enabled_streams) {
> +		dw_mipi_csi2rx_stop(csi2);
> +		pm_runtime_put(dev);
> +	}
>
>  	return ret;
>  }
>
> --
> 2.34.1
>