From mboxrd@z Thu Jan  1 00:00:00 1970
From: CK Hu <ck.hu@mediatek.com>
Subject: Re: [PATCH] drm/mediatek: add mt8183 dpi support
Date: Fri, 15 Feb 2019 00:13:29 +0800
Message-ID: <1550160809.6862.13.camel@mtksdaap41>
References: <20190211045059.11821-1-jitao.shi@mediatek.com>
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To: Jitao Shi <jitao.shi@mediatek.com>
Cc: Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>, Mark Rutland <mark.rutland@arm.com>, Ian Campbell <ijc+devicetree@hellion.org.uk>, Kumar Gala <galak@codeaurora.org>, linux-pwm@vger.kernel.org, David Airlie <airlied@linux.ie>, Matthias Brugger <matthias.bgg@gmail.com>, Thierry Reding <treding@nvidia.com>, Ajay Kumar <ajaykumar.rs@samsung.com>, Inki Dae <inki.dae@samsung.com>, Rahul Sharma <rahul.sharma@samsung.com>, Sean Paul <seanpaul@chromium.org>, Vincent Palatin <vpalatin@chromium.org>, Andy Yan <andy.yan@rock-chips.com>, Philipp Zabel <p.zabel@pengutronix.de>, Russell King <rmk+kernel@arm.linux.org.uk>, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-kernel
List-Id: devicetree@vger.kernel.org

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@mediatek.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

> +
>  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,
> +	},
>  	{ },
>  };
>