Re: [PATCH v2 4/7] media: synopsys: Add support for multiple streams

[Frank Li <Frank.li@nxp.com>]

On Thu, Apr 23, 2026 at 04:22:59PM +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@oss.nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

> Changes in v2:
> - Simplify error handling by keeping goto labels instead of early returns
> ---
>  drivers/media/platform/synopsys/dw-mipi-csi2rx.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> index d572d2eb3bcb..5a2e74d055c0 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;
>  };
> @@ -537,20 +538,26 @@ static int dw_mipi_csi2rx_enable_streams(struct v4l2_subdev *sd,
>  	if (ret)
>  		goto err;
>
> -	ret = dw_mipi_csi2rx_start(csi2);
> -	if (ret) {
> -		dev_err(dev, "failed to enable CSI hardware\n");
> -		goto err_pm_runtime_put;
> +	if (!csi2->enabled_streams) {
> +		ret = dw_mipi_csi2rx_start(csi2);
> +		if (ret) {
> +			dev_err(dev, "failed to enable CSI hardware\n");
> +			goto err_pm_runtime_put;
> +		}
>  	}
>
>  	ret = v4l2_subdev_enable_streams(remote_sd, remote_pad->index, mask);
>  	if (ret)
>  		goto err_csi_stop;
>
> +	csi2->enabled_streams |= streams_mask;
> +
>  	return 0;
>
>  err_csi_stop:
> -	dw_mipi_csi2rx_stop(csi2);
> +	/* Stop CSI hardware if no streams are enabled */
> +	if (!csi2->enabled_streams)
> +		dw_mipi_csi2rx_stop(csi2);
>  err_pm_runtime_put:
>  	pm_runtime_put(dev);
>  err:
> @@ -577,11 +584,16 @@ 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);
> +
>  	return ret;
>  }
>
>
> --
> 2.34.1
>