Re: [PATCH v3 07/15] media: qcom: camss: Capture VFE CSID dependency in a helper function

[Konrad Dybcio]

On 23.08.2023 12:44, Bryan O'Donoghue wrote:
> From sdm845 onwards we need to ensure the VFE is powered on prior to
> switching on the CSID.
And what's the symptom if we fail to ensure this? How can someone
adding support for another platform tell whether the match-list
should be expanded?

> 
> Alternatively we could model up the GDSCs and clocks the CSID needs
> without the VFE but, there's a real question of the legitimacy of such a
> use-case.
> 
> For now drawing a line at sdm845 and switching on the associated VFEs is
> a perfectly valid thing to do.
> 
> Rather than continually extend out this clause for at least two new SoCs
> with this same model - making the vfe_get/vfe_put path start to look
> like spaghetti we can encoded the dependency in a helper function.
> 
> Use csid_depends_vfe() for this purpose.
> 
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> ---
>  .../media/platform/qcom/camss/camss-csid.c    | 20 +++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/camss/camss-csid.c b/drivers/media/platform/qcom/camss/camss-csid.c
> index 08991b070bd61..fd04ed112b564 100644
> --- a/drivers/media/platform/qcom/camss/camss-csid.c
> +++ b/drivers/media/platform/qcom/camss/camss-csid.c
> @@ -146,6 +146,22 @@ static int csid_set_clock_rates(struct csid_device *csid)
>  	return 0;
>  }
>  
> +static bool csid_depends_vfe(u32 version)
toggle_vfe_before_csid?

> +{
> +	bool ret = false;
> +
> +	switch (version) {
> +	case CAMSS_845:
> +	case CAMSS_8250:
> +		ret = true;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return ret;
I'm not sure if it would be okay with like C conventions and
stuff, but this can be made shorter by returning from within
the switch statement

Konrad