linux-kernel - Re: [PATCH v2 13/26] drm/rockchip: dw-mipi-dsi: allow commands in panel

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Message-ID: <58846F3C.40904@rock-chips.com>
Date:   Sun, 22 Jan 2017 16:37:16 +0800
From:   Chris Zhong <zyw@...k-chips.com>
To:     John Keeping <john@...anate.com>,
        Mark Yao <mark.yao@...k-chips.com>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 13/26] drm/rockchip: dw-mipi-dsi: allow commands in
 panel_disable

Hi John



On 01/22/2017 12:31 AM, John Keeping wrote:
> Panel drivers may want to sent commands during the disable function, for
> example MIPI_DCS_SET_DISPLAY_OFF before the video signal ends.  In order
> to send commands we need to write to registers, so pclk must be enabled.
>
> While changing this, remove the unnecessary code after the panel
> unprepare call which seems to be a workaround for a specific panel and
> thus belongs in the panel driver.
>
> Signed-off-by: John Keeping <john@...anate.com>
> ---
> Unchanged in v2
> ---
>   drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 12 ++----------
>   1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index 7ada6d8ed143..290282e86d16 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -846,24 +846,16 @@ static void dw_mipi_dsi_encoder_disable(struct drm_encoder *encoder)
>   {
>   	struct dw_mipi_dsi *dsi = encoder_to_dsi(encoder);
>   
> -	drm_panel_disable(dsi->panel);
> -
>   	if (clk_prepare_enable(dsi->pclk)) {
>   		dev_err(dsi->dev, "%s: Failed to enable pclk\n", __func__);
>   		return;
>   	}
>   
> +	drm_panel_disable(dsi->panel);
> +
>   	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
>   	drm_panel_unprepare(dsi->panel);
> -	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_VID_MODE);
>   
> -	/*
> -	 * This is necessary to make sure the peripheral will be driven
> -	 * normally when the display is enabled again later.
> -	 */
> -	msleep(120);
> -
> -	dw_mipi_dsi_set_mode(dsi, DW_MIPI_DSI_CMD_MODE);
This workaround is from[0], I also think it should be deleted.

[0]
http://www.spinics.net/lists/dri-devel/msg77192.html


Reviewed-by: Chris Zhong <zyw@...k-chips.com>

>   	dw_mipi_dsi_disable(dsi);
>   	clk_disable_unprepare(dsi->pclk);
>   }