linux-kernel - Re: [PATCH v7 7/9] drm/mediatek: add dsi transfer function

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Message-ID: <1473837742.24354.28.camel@mtksdaap41>
Date:   Wed, 14 Sep 2016 15:22:22 +0800
From:   YT Shen <yt.shen@...iatek.com>
To:     CK Hu <ck.hu@...iatek.com>
CC:     <dri-devel@...ts.freedesktop.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Daniel Kurtz <djkurtz@...omium.org>,
        Mao Huang <littlecvr@...omium.org>,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        "Daniel Vetter" <daniel.vetter@...ll.ch>,
        Thierry Reding <thierry.reding@...il.com>,
        Jie Qiu <jie.qiu@...iatek.com>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        shaoming chen <shaoming.chen@...iatek.com>,
        Jitao Shi <jitao.shi@...iatek.com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <srv_heupstream@...iatek.com>,
        Sascha Hauer <kernel@...gutronix.de>,
        <yingjoe.chen@...iatek.com>, <emil.l.velikov@...il.com>
Subject: Re: [PATCH v7 7/9] drm/mediatek: add dsi transfer function

Hi CK,

On Wed, 2016-09-14 at 14:39 +0800, CK Hu wrote:
> Hi, YT:
> 
> On Wed, 2016-09-14 at 14:19 +0800, YT Shen wrote:
> > Hi CK,
> > 
> > On Tue, 2016-09-13 at 17:25 +0800, CK Hu wrote:
> > > Hi, YT:
> > > 
> > > On Mon, 2016-09-12 at 18:16 +0800, YT Shen wrote:
> > > > Hi CK,
> > > > 
> > > > On Wed, 2016-09-07 at 10:33 +0800, CK Hu wrote:
> > > > > Hi, YT:
> > > > > 
> > > > > On Fri, 2016-09-02 at 19:24 +0800, YT Shen wrote:
> > > > > > From: shaoming chen <shaoming.chen@...iatek.com>
> > > > > > 
> > > > > > add dsi read/write commands for transfer function
> > > > > > 
> > > > > > Signed-off-by: shaoming chen <shaoming.chen@...iatek.com>
> > > > > > ---
> > > > > >  drivers/gpu/drm/mediatek/mtk_dsi.c | 188 +++++++++++++++++++++++++++++++++++++
> > > > > >  1 file changed, 188 insertions(+)
> > > > > > 
> > > > > 
> > > > > [snip...]
> > > > > 
> > > > > >  
> > > > > > +static void mtk_dsi_irq_data_clear(struct mtk_dsi *dsi, u32 irq_bit)
> > > > > > +{
> > > > > > +	dsi->irq_data &= ~irq_bit;
> > > > > > +}
> > > > > > +
> > > > > 
> > > > > [snip...]
> > > > > 
> > > > > > +
> > > > > > +static s32 mtk_dsi_wait_for_irq_done(struct mtk_dsi *dsi, u32 irq_flag,
> > > > > > +				     unsigned int timeout)
> > > > > > +{
> > > > > > +	s32 ret = 0;
> > > > > > +	unsigned long jiffies = msecs_to_jiffies(timeout);
> > > > > > +
> > > > > > +	ret = wait_event_interruptible_timeout(_dsi_irq_wait_queue,
> > > > > > +					       dsi->irq_data & irq_flag,
> > > > > > +					       jiffies);
> > > > > > +	if (ret == 0) {
> > > > > > +		dev_info(dsi->dev, "Wait DSI IRQ(0x%08x) Timeout\n", irq_flag);
> > > > > > +
> > > > > > +		mtk_dsi_enable(dsi);
> > > > > > +		mtk_dsi_reset_engine(dsi);
> > > > > > +	}
> > > > > > +
> > > > > > +	return ret;
> > > > > > +}
> > > > > 
> > > > > I think mtk_dsi_irq_data_clear() and mtk_dsi_wait_for_irq_done() should
> > > > > be moved to the 6th patch [1] of this series because these two functions
> > > > > deal the irq control.
> > > > We will move mtk_dsi_irq_data_clear() to patch "drm/mediatek: add dsi
> > > > interrupt control" and put mtk_dsi_wait_for_irq_done() here, because it
> > > > is used in the transfer function.
> > > 
> > > mtk_dsi_irq_data_clear() is also only used in transfer function now. I
> > > think both function could be used for other application rather than
> > > transfer function, so these two function are general function for irq
> > > control.
> > We will rollback the changes here.  Move mtk_dsi_irq_data_clear() to
> > original place.
> > 
> > Add new functions could be used in the future will have problems.
> > warning: 'mtk_dsi_wait_for_irq_done' defined but not used
> > [-Wunused-function]
> >  static s32 mtk_dsi_wait_for_irq_done(struct mtk_dsi *dsi, u32 irq_flag,
> > warning: 'mtk_dsi_irq_data_clear' defined but not used
> > [-Wunused-function]
> >  static void mtk_dsi_irq_data_clear(struct mtk_dsi *dsi, u32 irq_bit)
> 
> Please refer to [1], '__maybe_unused' can fix your problem.
> 
> [1]
> http://lxr.free-electrons.com/source/drivers/gpu/drm/panel/panel-sharp-lq101r1sx01.c#L76
Add __maybe_unused just let GCC not produce a warning for this function.
So you want add patch like this?

[PATCH v7 6/9] drm/mediatek: add dsi interrupt control
+static __maybe_unused s32 mtk_dsi_wait_for_irq_done(struct mtk_dsi
*dsi, u32 irq_flag,

+static __maybe_unused void mtk_dsi_irq_data_set(struct mtk_dsi *dsi,
u32 irq_bit)

[PATCH v7 7/9] drm/mediatek: add dsi transfer function
-static __maybe_unused s32 mtk_dsi_wait_for_irq_done(struct mtk_dsi
*dsi, u32 irq_flag,
+static s32 mtk_dsi_wait_for_irq_done(struct mtk_dsi *dsi, u32 irq_flag,

-static __maybe_unused void mtk_dsi_irq_data_clear(struct mtk_dsi *dsi,
u32 irq_bit)
+static void mtk_dsi_irq_data_clear(struct mtk_dsi *dsi, u32 irq_bit)

Put the static function earlier and add __maybe_unused annotations.
Then remove _maybe_unused annotations later.  Or you want to keep
__maybe_unused annotations inside?  Sounds unnecessary, it is different
from your reference sharp_panel_read().

> 
> Regards,
> CK
> 
> > 
> > > Regards,
> > > CK
> > > 
> > > > 
> > > > Regards,
> > > > yt.shen
> > > > > 
> > > > > 
> > > > > [1] https://patchwork.kernel.org/patch/9310819/
> > > > > 
> > > > > 
> > > > > Regards,
> > > > > CK
> > > > > 
> > > > 
> > > > 
> > > 
> > > 
> > 
> > 
> 
>