Re: [PATCH 3/4] drm/mediatek: fine tune the dsi panel's power sequence - Chun-Kuang Hu

From: Chun-Kuang Hu <chunkuang.hu@kernel.org>
To: Jitao Shi <jitao.shi@mediatek.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>,
	srv_heupstream <srv_heupstream@mediatek.com>,
	huijuan.xie@mediatek.com, stonea168@163.com,
	Cawa Cheng <cawa.cheng@mediatek.com>,
	Rex-BC Chen <rex-bc.chen@mediatek.com>,
	"moderated list:ARM/Mediatek SoC support" 
	<linux-mediatek@lists.infradead.org>,
	yingjoe.chen@mediatek.com, eddie.huang@mediatek.com,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/4] drm/mediatek: fine tune the dsi panel's power sequence
Date: Sat, 24 Apr 2021 00:36:55 +0800	[thread overview]
Message-ID: <CAAOTY_-SKcX+4U5hKOgRaip-vk+ofEWe_g4VNUxFjN7LCprq1w@mail.gmail.com> (raw)
In-Reply-To: <20210420132614.150242-3-jitao.shi@mediatek.com>

Hi, Jitao:

Jitao Shi <jitao.shi@mediatek.com> 於 2021年4月20日 週二 下午9:26寫道：
>
> Add the drm_panel_prepare_power and drm_panel_unprepare_power control.
> Turn on panel power(drm_panel_prepare_power) and control before dsi
> enable. And then dsi enable, send dcs cmd in drm_panel_prepare, last
> turn on backlight.

Please describe WHY do you need this patch? Fix any bug?

>
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index a1ff152ef468..455fe582c6b5 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -615,10 +615,13 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>         dsi->data_rate = DIV_ROUND_UP_ULL(dsi->vm.pixelclock * bit_per_pixel,
>                                           dsi->lanes);
>
> +       if (panel_bridge_prepare_power(dsi->next_bridge))

ret = panel_bridge_prepare_power(dsi->next_bridge);
if (ret)

> +               DRM_INFO("can't prepare power the panel\n");

I think you should goto err_refcount;

> +
>         ret = clk_set_rate(dsi->hs_clk, dsi->data_rate);
>         if (ret < 0) {
>                 dev_err(dev, "Failed to set data rate: %d\n", ret);
> -               goto err_refcount;
> +               goto err_prepare_power;
>         }
>
>         phy_power_on(dsi->phy);
> @@ -661,7 +664,9 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>         clk_disable_unprepare(dsi->engine_clk);
>  err_phy_power_off:
>         phy_power_off(dsi->phy);
> -err_refcount:
> +err_prepare_power:
> +       if (panel_bridge_unprepare_power(dsi->next_bridge))

ret = panel_bridge_unprepare_power(dsi->next_bridge);

> +               DRM_INFO("Can't unprepare power the panel\n");
>         dsi->refcount--;
>         return ret;
>  }
> @@ -694,6 +699,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>         clk_disable_unprepare(dsi->digital_clk);
>
>         phy_power_off(dsi->phy);
> +
> +       if (panel_bridge_unprepare_power(dsi->next_bridge))

ret = panel_bridge_unprepare_power(dsi->next_bridge);

> +               DRM_INFO("Can't unprepare power the panel\n");
>  }
>
>  static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> --
> 2.25.1
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