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

[Gjorgji Rosikopulos (Consultant)]

Hi Bryan,

Thanks for the review,

On 9/11/2026 1:43 PM, Bryan O'Donoghue wrote:
> On 11/09/2026 07:22, 
> Gjorgji.Rosikopulos.gjorgji.rosikopulos@xxxxxxxxxxxxxxxx wrote:
>> From: Gjorgji Rosikopulos <gjorgji.rosikopulos@xxxxxxxxxxxxxxxx>
>>
>> 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@xxxxxxxxxxxxxxxx>
>> ---
>>   .../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.

I agree will switch to port until we have better name and change it everywhere.

> 
>> + *
>> + * 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.

Well initially they were int indeed, but i get some internal review comments to switch 
them to void, currently the implementation is writing only to the registers. 
So i am ok to switch to int return type, other option is to leave them as they are
and if needed in future to switch to int return type.

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