linux-kernel - Re: [PATCH] drm/mediatek: add mt8183 dpi support

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Message-ID: <1550541190.13121.2.camel@mszsdaap41>
Date:   Tue, 19 Feb 2019 09:53:10 +0800
From:   Jitao Shi <jitao.shi@...iatek.com>
To:     CK Hu <ck.hu@...iatek.com>
CC:     Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
        "Mark Rutland" <mark.rutland@....com>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Kumar Gala <galak@...eaurora.org>, <linux-pwm@...r.kernel.org>,
        David Airlie <airlied@...ux.ie>,
        "Matthias Brugger" <matthias.bgg@...il.com>,
        Thierry Reding <treding@...dia.com>,
        "Ajay Kumar" <ajaykumar.rs@...sung.com>,
        Inki Dae <inki.dae@...sung.com>,
        "Rahul Sharma" <rahul.sharma@...sung.com>,
        Sean Paul <seanpaul@...omium.org>,
        Vincent Palatin <vpalatin@...omium.org>,
        Andy Yan <andy.yan@...k-chips.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "Russell King" <rmk+kernel@....linux.org.uk>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        <srv_heupstream@...iatek.com>,
        Sascha Hauer <kernel@...gutronix.de>,
        <yingjoe.chen@...iatek.com>, <eddie.huang@...iatek.com>,
        <cawa.cheng@...iatek.com>, <bibby.hsieh@...iatek.com>,
        <stonea168@....com>
Subject: Re: [PATCH] drm/mediatek: add mt8183 dpi support

On Fri, 2019-02-15 at 00:13 +0800, CK Hu wrote:
> Hi, Jitao:
> 
> On Mon, 2019-02-11 at 12:50 +0800, Jitao Shi wrote:
> > MT8183 sample on rising and falling edge. It can reduce half data io.
> > 
> > Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c | 29 +++++++++++++++++++++++++++++
> >  1 file changed, 29 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index 62a9d47df948..610c23334047 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -117,6 +117,7 @@ struct mtk_dpi_conf {
> >  	unsigned int (*cal_factor)(int clock);
> >  	u32 reg_h_fre_con;
> >  	bool edge_sel_en;
> > +	bool dual_edge;
> >  };
> >  
> >  static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val, u32 mask)
> > @@ -353,6 +354,13 @@ static void mtk_dpi_config_disable_edge(struct mtk_dpi *dpi)
> >  		mtk_dpi_mask(dpi, dpi->conf->reg_h_fre_con, 0, EDGE_SEL_EN);
> >  }
> >  
> > +static void mtk_dpi_enable_dual_edge(struct mtk_dpi *dpi)
> > +{
> > +	mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE,
> > +		     DDR_EN | DDR_4PHASE);
> > +	mtk_dpi_mask(dpi, DPI_OUTPUT_SETTING, EDGE_SEL, EDGE_SEL);
> > +}
> 
> All these register exist in MT8173, if you do the same setting in
> MT8173, could it also sample on rising edge and falling edge?
> 
> Regards,
> CK

Hi CK,

MT8173 has those registers. But the hw function is removed.
So MT8173 doesn't support DPI dual edge sample.

Best Regards
Jitao

> 
> > +
> >  static void mtk_dpi_config_color_format(struct mtk_dpi *dpi,
> >  					enum mtk_dpi_out_color_format format)
> >  {
> > @@ -509,6 +517,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
> >  	mtk_dpi_config_color_format(dpi, dpi->color_format);
> >  	mtk_dpi_config_2n_h_fre(dpi);
> >  	mtk_dpi_config_disable_edge(dpi);
> > +	if (dpi->conf->dual_edge)
> > +		mtk_dpi_enable_dual_edge(dpi);
> >  	mtk_dpi_sw_reset(dpi, false);
> >  
> >  	return 0;
> > @@ -671,6 +681,16 @@ static unsigned int mt2701_calculate_factor(int clock)
> >  		return 2;
> >  }
> >  
> > +static unsigned int mt8183_calculate_factor(int clock)
> > +{
> > +	if (clock <= 27000)
> > +		return 8;
> > +	else if (clock <= 167000)
> > +		return 4;
> > +	else
> > +		return 2;
> > +}
> > +
> >  static const struct mtk_dpi_conf mt8173_conf = {
> >  	.cal_factor = mt8173_calculate_factor,
> >  	.reg_h_fre_con = 0xe0,
> > @@ -682,6 +702,12 @@ static const struct mtk_dpi_conf mt2701_conf = {
> >  	.edge_sel_en = true,
> >  };
> >  
> > +static const struct mtk_dpi_conf mt8183_conf = {
> > +	.cal_factor = mt8183_calculate_factor,
> > +	.reg_h_fre_con = 0xe0,
> > +	.dual_edge = true,
> > +};
> > +
> >  static int mtk_dpi_probe(struct platform_device *pdev)
> >  {
> >  	struct device *dev = &pdev->dev;
> > @@ -777,6 +803,9 @@ static const struct of_device_id mtk_dpi_of_ids[] = {
> >  	{ .compatible = "mediatek,mt8173-dpi",
> >  	  .data = &mt8173_conf,
> >  	},
> > +	{ .compatible = "mediatek,mt8183-dpi",
> > +	  .data = &mt8183_conf,
> > +	},
> >  	{ },
> >  };
> >  
> 
>