linux-kernel - Re: [PATCH] drm: mediatek: Modify dpi power on/off sequence.

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Message-ID: <c59a202cd31d46286eff441c6f42ec309486f334.camel@mediatek.com>
Date:   Tue, 8 Nov 2022 07:44:09 +0000
From:   CK Hu (胡俊光) <ck.hu@...iatek.com>
To:     "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>,
        Xinlei Lee (李昕磊) 
        <Xinlei.Lee@...iatek.com>, "airlied@...ux.ie" <airlied@...ux.ie>,
        Jitao Shi (石记涛) <jitao.shi@...iatek.com>
CC:     "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH] drm: mediatek: Modify dpi power on/off sequence.

Hi, Xinlei:

On Wed, 2022-10-12 at 15:48 +0800, xinlei.lee wrote:
> On Mon, 2022-09-05 at 21:53 +0800, xinlei.lee@...iatek.com wrote:
> > From: Xinlei Lee <xinlei.lee@...iatek.com>
> > 
> > Modify dpi power on/off sequence so that the first gpio operation
> > will take effect.
> > 
> > Fixes: 6bd4763fd532 ("drm/mediatek: set dpi pin mode to gpio low to
> > avoid leakage
> > current")
> > 
> > Signed-off-by: Xinlei Lee <xinlei.lee@...iatek.com>
> > 
> > ---
> > Base on the branch of Linux-next/master.
> > Because dpi power_on/off is protected by dpi->refcount, the first
> > time
> > it cannot be powered on and off successfully, it will cause
> > leakage.
> > ---
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index 630a4e301ef6..2ce1a39ce3bf 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -462,9 +462,6 @@ static void mtk_dpi_power_off(struct mtk_dpi
> > *dpi)
> >  	if (--dpi->refcount != 0)
> >  		return;
> >  
> > -	if (dpi->pinctrl && dpi->pins_gpio)
> > -		pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);
> > -
> >  	mtk_dpi_disable(dpi);
> >  	clk_disable_unprepare(dpi->pixel_clk);
> >  	clk_disable_unprepare(dpi->engine_clk);
> > @@ -489,9 +486,6 @@ static int mtk_dpi_power_on(struct mtk_dpi
> > *dpi)
> >  		goto err_pixel;
> >  	}
> >  
> > -	if (dpi->pinctrl && dpi->pins_dpi)
> > -		pinctrl_select_state(dpi->pinctrl, dpi->pins_dpi);
> > -
> >  	return 0;
> >  
> >  err_pixel:
> > @@ -721,6 +715,9 @@ static void mtk_dpi_bridge_disable(struct
> > drm_bridge *bridge)
> >  {
> >  	struct mtk_dpi *dpi = bridge_to_dpi(bridge);
> >  
> > +	if (dpi->pinctrl && dpi->pins_gpio)
> > +		pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);

I think this should be placed after mtk_dpi_power_off().

> > +
> >  	mtk_dpi_power_off(dpi);
> >  }
> >  
> > @@ -728,6 +725,9 @@ static void mtk_dpi_bridge_enable(struct
> > drm_bridge *bridge)
> >  {
> >  	struct mtk_dpi *dpi = bridge_to_dpi(bridge);
> >  
> > +	if (dpi->pinctrl && dpi->pins_dpi)
> > +		pinctrl_select_state(dpi->pinctrl, dpi->pins_dpi);
> > +
> >  	mtk_dpi_power_on(dpi);
> >  	mtk_dpi_set_display_mode(dpi, &dpi->mode);
> >  	mtk_dpi_enable(dpi);
> 
> Hi CK,
> 
> Gentle ping for this patch, if there is anything I need to modify,
> please kindly let me know.
> 
> Best Regards!
> xinlei
>