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

Konrad Dybcio
2023-08-26T10:02:42Z

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@linaro.org>
> ---
> .../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