Re: [PATCH 2/8] media: qcom: camss: Add streams API hw_ops to CSID interface

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 11/09/2026 07:22, 
Gjorgji.Rosikopulos.gjorgji.rosikopulos@oss.qualcomm.com wrote:
> From: Gjorgji Rosikopulos <gjorgji.rosikopulos@oss.qualcomm.com>
> 
> Add configure_rx/enable_stream/disable_stream to struct csid_hw_ops:
> per-stream hardware operations needed to support the V4L2 subdev
> streams API, where the CSID Rx front-end is configured once
> independently of the per-stream RDI programming.
> 
> No functional change: these are new optional hw_ops entries, not yet
> implemented by any backend or called by any code path.
> 
> Signed-off-by: Gjorgji Rosikopulos <gjorgji.rosikopulos@oss.qualcomm.com>
> ---
>   .../media/platform/qcom/camss/camss-csid.h    | 43 +++++++++++++++++++
>   1 file changed, 43 insertions(+)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss-csid.h b/drivers/media/platform/qcom/camss/camss-csid.h
> index 5296b10f6bac..90ee611b9092 100644
> --- a/drivers/media/platform/qcom/camss/camss-csid.h
> +++ b/drivers/media/platform/qcom/camss/camss-csid.h
> @@ -74,6 +74,25 @@ struct csid_phy_config {
>   
>   struct csid_device;
>   
> +/*
> + * struct csid_hw_ops - CSID hardware version specific operations
> + *
> + * configure_stream() is the legacy (non-streams-API) path and is mutually
> + * exclusive with enable_stream()/disable_stream() - a given CSID instance
> + * uses one family or the other, chosen by streams_enable.
> + *
> + * stream_id, as passed to enable_stream()/disable_stream(), is a hardware
> + * RDI/PIX port index in [0, MSM_CSID_MAX_SRC_STREAMS). It is currently
> + * always equal to pad - MSM_CSID_PAD_FIRST_SRC (multi-pad, 1:1
> + * pad-to-port mapping).

Lets not mix and match names. There has historically been a huge amount 
of sin and liberty taken, not the good kind unfortunately - with port_id 
and write-master.

port I believe is the misnomer we are currently stuck with - so lets 
continue to use it until a more crisp naming convention happens.

> + *
> + * configure_rx() is called once, on the transition from zero to non-zero
> + * active sink streams, strictly before the first enable_stream() call.
> + * enable_stream()/disable_stream() calls are always made under the
> + * subdev's active-state lock (core-enforced via
> + * v4l2_subdev_enable_streams()/disable_streams()), so hw_ops
> + * implementations don't need their own serialization.
> + */
>   struct csid_hw_ops {
>   	/*
>   	 * configure_stream - Configures and starts CSID input stream
> @@ -81,6 +100,30 @@ struct csid_hw_ops {
>   	 */
>   	void (*configure_stream)(struct csid_device *csid, u8 enable);
>   
> +	/*
> +	 * configure_rx - Configure the CSID Rx front-end
> +	 * @csid: CSID device
> +	 *
> +	 * Called once, when the first stream is enabled.
> +	 */
> +	void (*configure_rx)(struct csid_device *csid);
> +
> +	/*
> +	 * enable_stream - Enable a single CSID output stream
> +	 * @csid: CSID device
> +	 * @stream_id: stream id to enable
> +	 * @vc: virtual channel to program
> +	 * @dt: data type to program
> +	 */
> +	void (*enable_stream)(struct csid_device *csid, u32 stream_id, u8 vc, u8 dt);
> +
> +	/*
> +	 * disable_stream - Disable a single CSID output stream
> +	 * @csid: CSID device
> +	 * @stream_id: stream id to disable
> +	 */
> +	void (*disable_stream)(struct csid_device *csid, u32 stream_id);
> +

Seems odd that none of these have integer return types to propagate errors.

>   	/*
>   	 * configure_testgen_pattern - Validates and configures output pattern mode
>   	 * of test pattern generator