linux-kernel - Re: [PATCH v5 25/34] drm/mediatek: mtk_hdmi: Remove ifdef for CONFIG_PM

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Message-ID: <226a2b712dfb082e94bd0b26026264362f69ea60.camel@mediatek.com>
Date: Tue, 11 Feb 2025 02:16:33 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>
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	<junzhi.zhao@...iatek.com>
Subject: Re: [PATCH v5 25/34] drm/mediatek: mtk_hdmi: Remove ifdef for
 CONFIG_PM_SLEEP

On Mon, 2025-02-10 at 12:43 +0100, AngeloGioacchino Del Regno wrote:
> External email : Please do not click links or open attachments until you have verified the sender or the content.
> 
> 
> Il 07/02/25 07:10, CK Hu (胡俊光) ha scritto:
> > Hi, Angelo:
> > 
> > On Mon, 2025-01-13 at 15:52 +0100, AngeloGioacchino Del Regno wrote:
> > > External email : Please do not click links or open attachments until you have verified the sender or the content.
> > > 
> > > 
> > > Since the SIMPLE_DEV_PM_OPS macro and the pm pointer are anyway
> > > defined when CONFIG_PM_SLEEP is not set, remove the ifdef for it
> > > and indicate that the mtk_hdmi_{remove,suspend} functions may be
> > > unused (as they are, in case PM support is not built-in).
> > > 
> > > While at it, to improve readability, also compress the
> > > SIMPLE_DEV_PM_OPS declaration as it even fits in less
> > > than 80 columns.
> > > 
> > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> > > ---
> > >   drivers/gpu/drm/mediatek/mtk_hdmi.c | 10 ++++------
> > >   1 file changed, 4 insertions(+), 6 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> > > index 0ec3bfe528f8..f6b463aaba47 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> > > @@ -1692,8 +1692,7 @@ static void mtk_hdmi_remove(struct platform_device *pdev)
> > >          mtk_hdmi_clk_disable_audio(hdmi);
> > >   }
> > > 
> > > -#ifdef CONFIG_PM_SLEEP
> > > -static int mtk_hdmi_suspend(struct device *dev)
> > > +static __maybe_unused int mtk_hdmi_suspend(struct device *dev)
> > 
> > I see many driver use CONFIG_PM_SLEEP,
> > and SIMPLE_DEV_PM_OPS() is defined to support suspend/resume function is not exist when CONFIG_PM_SLEEP is not defined,
> > so there is no strong purpose to apply this patch.
> > 
> 
> This allows to improve the compile time coverage and at the same, this will not
> increase the binary size of this driver, because the compiler (or, all of the
> linkers associated to the compilers that can be used to build the kernel, anyway!)
> will drop the two functions when CONFIG_PM_SLEEP is *not* defined.
> 
> Also:
>   * This ifdef is redundant, as it's already handled by SIMPLE_DEV_PM_OPS
>   * Removing ugly ifdeffery increases human readability while also slightly
>     reducing the number of lines

Add these information in commit message, then

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> 
> Regards,
> Angelo
> 
> > Regards,
> > CK
> > 
> > >   {
> > >          struct mtk_hdmi *hdmi = dev_get_drvdata(dev);
> > > 
> > > @@ -1702,7 +1701,7 @@ static int mtk_hdmi_suspend(struct device *dev)
> > >          return 0;
> > >   }
> > > 
> > > -static int mtk_hdmi_resume(struct device *dev)
> > > +static __maybe_unused int mtk_hdmi_resume(struct device *dev)
> > >   {
> > >          struct mtk_hdmi *hdmi = dev_get_drvdata(dev);
> > >          int ret = 0;
> > > @@ -1715,9 +1714,8 @@ static int mtk_hdmi_resume(struct device *dev)
> > > 
> > >          return 0;
> > >   }
> > > -#endif
> > > -static SIMPLE_DEV_PM_OPS(mtk_hdmi_pm_ops,
> > > -                        mtk_hdmi_suspend, mtk_hdmi_resume);
> > > +
> > > +static SIMPLE_DEV_PM_OPS(mtk_hdmi_pm_ops, mtk_hdmi_suspend, mtk_hdmi_resume);
> > > 
> > >   static const struct mtk_hdmi_conf mtk_hdmi_conf_mt2701 = {
> > >          .tz_disabled = true,
> > > --
> > > 2.47.0
> > > 
> > 
>