linux-kernel - Re: [PATCH v6 7/7] pinctrl: qcom: Update clock voting as optional

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Date:   Fri, 18 Feb 2022 18:46:35 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Srinivasa Rao Mandadapu <quic_srivasam@...cinc.com>,
        agross@...nel.org, alsa-devel@...a-project.org,
        bgoswami@...eaurora.org, bjorn.andersson@...aro.org,
        broonie@...nel.org, devicetree@...r.kernel.org,
        judyhsiao@...omium.org, lgirdwood@...il.com,
        linux-arm-msm@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, perex@...ex.cz,
        quic_plai@...cinc.com, robh+dt@...nel.org, rohitkr@...eaurora.org,
        tiwai@...e.com
Cc:     Venkata Prasad Potturu <quic_potturu@...cinc.com>
Subject: Re: [PATCH v6 7/7] pinctrl: qcom: Update clock voting as optional

Quoting Srinivas Kandagatla (2022-02-16 07:38:02)
>
>
> On 16/02/2022 14:41, Srinivasa Rao Mandadapu wrote:
> >
> > On 2/16/2022 7:50 PM, Srinivas Kandagatla wrote:
> > Thanks for Your Time Srini!!!
> >>
> >> On 14/02/2022 15:19, Srinivasa Rao Mandadapu wrote:
> >>> diff --git a/drivers/pinctrl/qcom/pinctrl-sc7280-lpass-lpi.c
> >>> b/drivers/pinctrl/qcom/pinctrl-sc7280-lpass-lpi.c
> >>> index 5bf30d97..4277e31 100644
> >>> --- a/drivers/pinctrl/qcom/pinctrl-sc7280-lpass-lpi.c
> >>> +++ b/drivers/pinctrl/qcom/pinctrl-sc7280-lpass-lpi.c
> >>> @@ -143,6 +143,7 @@ static const struct lpi_pinctrl_variant_data
> >>> sc7280_lpi_data = {
> >>>       .ngroups = ARRAY_SIZE(sc7280_groups),
> >>>       .functions = sc7280_functions,
> >>>       .nfunctions = ARRAY_SIZE(sc7280_functions),
> >>> +    .is_clk_optional = 1,
> >>
> >> This is forcefully set assuming that sc7280 is always used in ADSP
> >> bypass mode. Which is not correct.
> >>
> >> Can't you use devm_clk_bulk_get_optional instead?
> >
> > Yes. Agreed. Initially used devm_clk_bulk_get_optional, but Bjorn
> > suggested for conditional check instead of optional.
> >
> > Again Shall we go for optional clock voting?
>
> That means that the condition has to be dynamic based on the platform
> using DSP or not. Which is impossible to deduce without some help from DT.
>
> I would prefer to stay with optional clock unless Bjorn has some strong
> objection on not using int.

I think we need the combination of optional API and bool flag. My
understanding is it's optional on sc7280, but not on the previous
revision, so we want to be very strict on previous revision and less
strict on sc7280. Hence the flag. Maybe we should change it to
clk_required and then assume optional going forward. Then the callsite
can use one or the other API?