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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 29 Nov 2022 11:53:10 +0100
Message-ID: <CAMuHMdUfRJmy56eO=ET-Togg-EOgxSjnTgAUYWmixD_zVonipA@mail.gmail.com>
Subject: Re: [PATCH] ASoC: qcom: lpass-sc7180: Add system suspend/resume PM ops
To:     Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
Cc:     agross@kernel.org, andersson@kernel.org, lgirdwood@gmail.com,
        broonie@kernel.org, robh+dt@kernel.org, quic_plai@quicinc.com,
        bgoswami@quicinc.com, perex@perex.cz, tiwai@suse.com,
        srinivas.kandagatla@linaro.org, quic_rohkumar@quicinc.com,
        linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org, swboyd@chromium.org,
        judyhsiao@chromium.org, devicetree@vger.kernel.org
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Precedence: bulk

Hi Srinivasa,

On Tue, Nov 29, 2022 at 11:36 AM Srinivasa Rao Mandadapu
<quic_srivasam@quicinc.com> wrote:
> On 11/29/2022 1:23 PM, Geert Uytterhoeven wrote:
> > On Mon, Nov 28, 2022 at 8:50 AM Srinivasa Rao Mandadapu
> > <quic_srivasam@quicinc.com> wrote:
> >> Update lpass sc7180 platform driver with PM ops, such as
> >> system supend and resume callbacks.
> >> This update is required to disable clocks during supend and
> >> avoid XO shutdown issue.
> >>
> >> Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
> >> Tested-by: Rahul Ajmeriya <quic_rajmeriy@quicinc.com>
> > Thanks for your patch, which is now commit 2d68148f8f85ca5a ("ASoC:
> > qcom: lpass-sc7180: Add system suspend/resume PM ops") in next-20221129.
> >
> >> --- a/sound/soc/qcom/lpass-sc7180.c
> >> +++ b/sound/soc/qcom/lpass-sc7180.c
> >> @@ -12,6 +12,7 @@
> >>   #include <linux/module.h>
> >>   #include <linux/of.h>
> >>   #include <linux/platform_device.h>
> >> +#include <linux/pm_runtime.h>
> >>   #include <dt-bindings/sound/sc7180-lpass.h>
> >>   #include <sound/pcm.h>
> >>   #include <sound/soc.h>
> >> @@ -156,10 +157,34 @@ static int sc7180_lpass_exit(struct platform_device *pdev)
> >>          struct lpass_data *drvdata = platform_get_drvdata(pdev);
> >>
> >>          clk_bulk_disable_unprepare(drvdata->num_clks, drvdata->clks);
> >> +       return 0;
> >> +}
> >> +
> >> +static int sc7180_lpass_dev_resume(struct device *dev)
> >> +{
> >> +       int ret = 0;
> >> +       struct lpass_data *drvdata = dev_get_drvdata(dev);
> >>
> >> +       ret = clk_bulk_prepare_enable(drvdata->num_clks, drvdata->clks);
> >> +       if (ret) {
> >> +               dev_err(dev, "sc7180 clk prepare and enable failed\n");
> >> +               return ret;
> >> +       }
> >> +       return ret;
> >> +}
> >> +
> >> +static int sc7180_lpass_dev_suspend(struct device *dev)
> >> +{
> >> +       struct lpass_data *drvdata = dev_get_drvdata(dev);
> >> +
> >> +       clk_bulk_disable_unprepare(drvdata->num_clks, drvdata->clks);
> >>          return 0;
> >>   }
> > noreply@ellerman.id.au reports for e.g. m68k-allmodconfig:
> >
> >      sound/soc/qcom/lpass-sc7180.c:179:12: error:
> > 'sc7180_lpass_dev_suspend' defined but not used
> > [-Werror=unused-function]
> >      sound/soc/qcom/lpass-sc7180.c:166:12: error:
> > 'sc7180_lpass_dev_resume' defined but not used
> > [-Werror=unused-function]
> >
> >> +static const struct dev_pm_ops sc7180_lpass_pm_ops = {
> >> +       SET_SYSTEM_SLEEP_PM_OPS(sc7180_lpass_dev_suspend, sc7180_lpass_dev_resume)
> >> +};
> > Please use DEFINE_SIMPLE_DEV_PM_OPS()...
> Actually, we need to use this patch in in previous kernels 5.4 and 5.15.
> I think these changes won't apply on previous kernel.
> Hence ignoring for now and will take care next time.

In that case you should add __maybe_unused tags to
sc7180_lpass_dev_suspend() and sc7180_lpass_dev_resume() first, so it
can be backported to 5.4 and 5.15, and do the DEFINE_SIMPLE_DEV_PM_OPS()
conversion later.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds