linux-kernel - Re: [PATCH RFT 02/20] clk: qcom: smd-rpm: Add .is

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Date:   Mon, 6 Mar 2023 03:05:48 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Shawn Guo <shawn.guo@...aro.org>
Subject: Re: [PATCH RFT 02/20] clk: qcom: smd-rpm: Add .is_prepared hook

On Sat, 4 Mar 2023 at 15:27, Konrad Dybcio <konrad.dybcio@...aro.org> wrote:
>
> From: Shawn Guo <shawn.guo@...aro.org>
>
> The RPM clocks are enabled/disabled through clk framework prepare/unprepare
> hooks.  Without .is_prepared hook, those unused RPM clocks will not be
> disabled by core function clk_unprepare_unused_subtree(), because
> clk_core_is_prepared() always returns 0.
>
> Add .is_prepared hook to clk_ops and return the clock prepare (enable)
> state, so that those unused RPM clocks can be disabled by clk framework.

Does it make any difference? Without this patch the clock framework
depends on core->prepare_count to judge whether the clock should be
unprepared. With this patch in place, it will depend on r->enabled,
which is more or less the same thing.
Probably there is one category, the prepared-but-not-enabled clocks.

>
> Signed-off-by: Shawn Guo <shawn.guo@...aro.org>
> [Konrad: rebase, don't duplicate the enable func]
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> ---
>  drivers/clk/qcom/clk-smd-rpm.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/clk/qcom/clk-smd-rpm.c b/drivers/clk/qcom/clk-smd-rpm.c
> index ecacfbc4a16c..cce7daa97c1e 100644
> --- a/drivers/clk/qcom/clk-smd-rpm.c
> +++ b/drivers/clk/qcom/clk-smd-rpm.c
> @@ -438,6 +438,7 @@ static const struct clk_ops clk_smd_rpm_ops = {
>         .round_rate     = clk_smd_rpm_round_rate,
>         .recalc_rate    = clk_smd_rpm_recalc_rate,
>         .is_enabled     = clk_smd_rpm_is_enabled,
> +       .is_prepared    = clk_smd_rpm_is_enabled,
>  };
>
>  static const struct clk_ops clk_smd_rpm_branch_ops = {
> @@ -445,6 +446,7 @@ static const struct clk_ops clk_smd_rpm_branch_ops = {
>         .unprepare      = clk_smd_rpm_unprepare,
>         .recalc_rate    = clk_smd_rpm_recalc_rate,
>         .is_enabled     = clk_smd_rpm_is_enabled,
> +       .is_prepared    = clk_smd_rpm_is_enabled,
>  };
>
>  DEFINE_CLK_SMD_RPM_BRANCH_A(bi_tcxo, QCOM_SMD_RPM_MISC_CLK, 0, 19200000);
>
> --
> 2.39.2
>


-- 
With best wishes
Dmitry