linux-kernel - Re: [PATCH] drm/mediatek: mtk_dsi: Add support for High Speed (HS) mode

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Message-ID: <CAAOTY_8roBx1nPqvaon6F-ittiotJfi_aZu-1jgwHZVbQ_uh0A@mail.gmail.com>
Date: Fri, 16 Jan 2026 23:51:34 +0000
From: Chun-Kuang Hu <chunkuang.hu@...nel.org>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: chunkuang.hu@...nel.org, p.zabel@...gutronix.de, airlied@...il.com, 
	simona@...ll.ch, matthias.bgg@...il.com, dri-devel@...ts.freedesktop.org, 
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, bisson.gary@...il.com, 
	kernel@...labora.com
Subject: Re: [PATCH] drm/mediatek: mtk_dsi: Add support for High Speed (HS) mode

Hi, Angelo:

AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com> 於
2026年1月8日週四 上午10:20寫道：
>
> Up until now, the MediaTek DSI Controller has always been working
> in Low Power Mode (LPM), as this driver has always ignored the
> MIPI_DSI_MSG_USE_LPM flag hence never setting HS mode.
>
> In the current state of the driver the only thing that is needed
> to add support for DSI High Speed (HS) transmit is to simply set
> the "HSTX" config bit in the configuration register.
>
> Check if flag MIPI_DSI_MSG_USE_LPM is set and, if not, set HSTX.

Applied to mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index e4953d5cb6a8..a90cae9512c5 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -155,6 +155,7 @@
>  #define SHORT_PACKET                   0
>  #define LONG_PACKET                    2
>  #define BTA                            BIT(2)
> +#define HSTX                           BIT(3)
>  #define DATA_ID                                GENMASK(15, 8)
>  #define DATA_0                         GENMASK(23, 16)
>  #define DATA_1                         GENMASK(31, 24)
> @@ -1177,6 +1178,9 @@ static void mtk_dsi_cmdq(struct mtk_dsi *dsi, const struct mipi_dsi_msg *msg)
>         else
>                 config = (msg->tx_len > 2) ? LONG_PACKET : SHORT_PACKET;
>
> +       if (!(msg->flags & MIPI_DSI_MSG_USE_LPM))
> +               config |= HSTX;
> +
>         if (msg->tx_len > 2) {
>                 cmdq_size = 1 + (msg->tx_len + 3) / 4;
>                 cmdq_off = 4;
> --
> 2.52.0
>