linux-kernel - Re: [PATCH 3/3] drm/mediatek: add mt8183 dsi driver support

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Message-ID: <CANMq1KBR-CpjAtj6qTEjK8PA2DUW3w_-OP_EyE7uoaojGLoGLg@mail.gmail.com>
Date:   Thu, 14 Feb 2019 13:54:44 +0800
From:   Nicolas Boichat <drinkcat@...omium.org>
To:     Jitao Shi <jitao.shi@...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, lkml <linux-kernel@...r.kernel.org>,
        dri-devel@...ts.freedesktop.org,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>, srv_heupstream@...iatek.com,
        Sascha Hauer <kernel@...gutronix.de>,
        Yingjoe Chen <yingjoe.chen@...iatek.com>,
        Eddie Huang <eddie.huang@...iatek.com>,
        cawa cheng <cawa.cheng@...iatek.com>,
        Bibby Hsieh (謝濟遠) 
        <bibby.hsieh@...iatek.com>, CK HU <ck.hu@...iatek.com>,
        stonea168@....com
Subject: Re: [PATCH 3/3] drm/mediatek: add mt8183 dsi driver support

On Thu, Feb 14, 2019 at 12:43 PM Jitao Shi <jitao.shi@...iatek.com> wrote:
>
> MT8183 dsi has two changes with mt8173.
> 1. Add the register double buffer control, but we no need it, So make
>    it default off.

Can you describe a little bit more what this is about? That's shadow
registers, right?

> 2. Add picture size control.
>
> Signed-off-by: Jitao Shi <jitao.shi@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 80db02a25cb0..20cb53f05d42 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -78,6 +78,7 @@
>  #define DSI_VBP_NL             0x24
>  #define DSI_VFP_NL             0x28
>  #define DSI_VACT_NL            0x2C
> +#define DSI_SIZE_CON           0x38
>  #define DSI_HSA_WC             0x50
>  #define DSI_HBP_WC             0x54
>  #define DSI_HFP_WC             0x58
> @@ -131,7 +132,10 @@
>  #define VM_CMD_EN                      BIT(0)
>  #define TS_VFP_EN                      BIT(5)
>
> -#define DSI_CMDQ0              0x180

As I said earlier, move this to 2/3.

> +#define DSI_SHADOW_DEBUG       0x190U
> +#define FORCE_COMMIT           BIT(0)
> +#define BYPASS_SHADOW          BIT(1)
> +
>  #define CONFIG                         (0xff << 0)
>  #define SHORT_PACKET                   0
>  #define LONG_PACKET                    2
> @@ -158,6 +162,7 @@ struct phy;
>
>  struct mtk_dsi_driver_data {
>         const u32 reg_cmdq_off;
> +       bool has_size_ctl;
>  };
>
>  struct mtk_dsi {
> @@ -426,6 +431,9 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
>         writel(vm->vfront_porch, dsi->regs + DSI_VFP_NL);
>         writel(vm->vactive, dsi->regs + DSI_VACT_NL);
>
> +       if (dsi->driver_data->has_size_ctl)
> +               writel(vm->vactive << 16 | vm->hactive, dsi->regs + DSI_SIZE_CON);
> +
>         horizontal_sync_active_byte = (vm->hsync_len * dsi_tmp_buf_bpp - 10);
>
>         if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> @@ -595,6 +603,9 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>         }
>
>         mtk_dsi_enable(dsi);
> +
> +       /* DSI no need this double buffer, disable it when writing register */

"DSI does not need double buffering, disable it when writing register"

> +       writel(FORCE_COMMIT | BYPASS_SHADOW, dsi->regs + DSI_SHADOW_DEBUG);

So you do this on all MT* variants, is that ok?

>         mtk_dsi_reset_engine(dsi);
>         mtk_dsi_phy_timconfig(dsi);
>
> @@ -1090,11 +1101,18 @@ static const struct mtk_dsi_driver_data mt2701_dsi_driver_data = {
>         .reg_cmdq_off = 0x180,
>  };
>
> +static const struct mtk_dsi_driver_data mt8183_dsi_driver_data = {
> +       .reg_cmdq_off = 0x200,
> +       .has_size_ctl = true,
> +};
> +
>  static const struct of_device_id mtk_dsi_of_match[] = {
>         { .compatible = "mediatek,mt2701-dsi",
>           .data = &mt2701_dsi_driver_data },
>         { .compatible = "mediatek,mt8173-dsi",
>           .data = &mt8173_dsi_driver_data },
> +       { .compatible = "mediatek,mt8183-dsi",
> +         .data = &mt8183_dsi_driver_data },
>         { },
>  };
>
> --
> 2.20.1
>