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References: <20210525121448.30075-1-rex-bc.chen@mediatek.com> <20210525121448.30075-2-rex-bc.chen@mediatek.com>
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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Wed, 26 May 2021 08:01:11 +0800
Message-ID: <CAAOTY__aasihVxC72f7b_R-=UcR85Z1G9M8TxUS9dBrad-aRxQ@mail.gmail.com>
Subject: Re: [v4,PATCH 1/3] drm/mediatek: dpi dual edge sample mode support
To:     Rex-BC Chen <rex-bc.chen@mediatek.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        DTML <devicetree@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Project_Global_Chrome_Upstream_Group@mediatek.com,
        Jitao Shi <jitao.shi@mediatek.com>
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Hi, Rex:

Rex-BC Chen <rex-bc.chen@mediatek.com> =E6=96=BC 2021=E5=B9=B45=E6=9C=8825=
=E6=97=A5 =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=888:15=E5=AF=AB=E9=81=93=EF=BC=
=9A
>
> DPI can sample on falling, rising or both edge.
> When DPI sample the data both rising and falling edge.
> It can reduce half data io pins.
> Use num_output_fmts to determine whether it is dual edge mode.
>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediate=
k/mtk_dpi.c
> index bea91c81626e..d3b883c97aaf 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -83,6 +83,7 @@ struct mtk_dpi {
>         struct pinctrl *pinctrl;
>         struct pinctrl_state *pins_gpio;
>         struct pinctrl_state *pins_dpi;
> +       bool ddr_edge_sel;

I would like to keep output_fmt instead of ddr_edge_sel.
Initialize output_fmt to MEDIA_BUS_FMT_RGB888_1X24 in this patch.

>         int refcount;
>  };
>
> @@ -122,6 +123,8 @@ struct mtk_dpi_conf {
>         u32 reg_h_fre_con;
>         u32 max_clock_khz;
>         bool edge_sel_en;
> +       const u32 *output_fmts;
> +       u32 num_output_fmts;

Move these to next patch.

>  };
>
>  static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val, u32 m=
ask)
> @@ -381,6 +384,16 @@ static void mtk_dpi_config_color_format(struct mtk_d=
pi *dpi,
>         }
>  }
>
> +static void mtk_dpi_dual_edge(struct mtk_dpi *dpi)
> +{
> +       if (dpi->conf->num_output_fmts > 1) {
> +               mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE,
> +                            DDR_EN | DDR_4PHASE);
> +               mtk_dpi_mask(dpi, DPI_OUTPUT_SETTING,
> +                            dpi->ddr_edge_sel ? EDGE_SEL : 0, EDGE_SEL);
> +       }

if (dpi->output_fmt =3D=3D MEDIA_BUS_FMT_RGB888_2X12_LE) ||
   (dpi->output_fmt =3D=3D MEDIA_BUS_FMT_RGB888_2X12_BE) {
    mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE, DDR_EN |
DDR_4PHASE);
    mtk_dpi_mask(dpi, DPI_OUTPUT_SETTING,
                             dpi->output_fmt =3D=3D
MEDIA_BUS_FMT_RGB888_2X12_LE ? EDGE_SEL : 0, EDGE_SEL);
} else {
    mtk_dpi_mask(dpi, DPI_DDR_SETTING, DDR_EN | DDR_4PHASE, 0);
}

> +}
> +
>  static void mtk_dpi_power_off(struct mtk_dpi *dpi)
>  {
>         if (WARN_ON(dpi->refcount =3D=3D 0))
> @@ -455,7 +468,8 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *d=
pi,
>         pll_rate =3D clk_get_rate(dpi->tvd_clk);
>
>         vm.pixelclock =3D pll_rate / factor;
> -       clk_set_rate(dpi->pixel_clk, vm.pixelclock);
> +       clk_set_rate(dpi->pixel_clk,
> +                    vm.pixelclock * ((dpi->conf->num_output_fmts > 1) ? =
2 : 1));

if (dpi->output_fmt =3D=3D MEDIA_BUS_FMT_RGB888_2X12_LE) ||
   (dpi->output_fmt =3D=3D MEDIA_BUS_FMT_RGB888_2X12_BE)
    clk_set_rate(dpi->pixel_clk, vm.pixelclock * 2);
else
    clk_set_rate(dpi->pixel_clk, vm.pixelclock);

>         vm.pixelclock =3D clk_get_rate(dpi->pixel_clk);
>
>         dev_dbg(dpi->dev, "Got  PLL %lu Hz, pixel clock %lu Hz\n",
> @@ -519,6 +533,7 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *d=
pi,
>         mtk_dpi_config_yc_map(dpi, dpi->yc_map);
>         mtk_dpi_config_color_format(dpi, dpi->color_format);
>         mtk_dpi_config_2n_h_fre(dpi);
> +       mtk_dpi_dual_edge(dpi);
>         mtk_dpi_config_disable_edge(dpi);
>         mtk_dpi_sw_reset(dpi, false);
>
> --
> 2.18.0
>