[PATCH v2 1/4] drm: rcar-du: dsi: Properly stop video mode TX

[Laurent Pinchart]

Hi Tomi,

Thank you for the patch.

On Mon, Aug 22, 2022 at 04:05:09PM +0300, Tomi Valkeinen wrote:
> From: Tomi Valkeinen <tomi.valkeinen+renesas at ideasonboard.com>
> 
> The driver does not explicitly stop the video mode transmission when
> disabling the output. While this doesn't seem to be causing any issues,
> lets follow the steps described in the documentation and add a
> rcar_mipi_dsi_stop_video() which stop the video mode transmission. This
> function will also be used in later patches to stop the video
> transmission even if the DSI IP is not shut down.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas at ideasonboard.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c | 29 +++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> index 62f7eb84ab01..7f2be490fcf8 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_mipi_dsi.c
> @@ -542,6 +542,34 @@ static int rcar_mipi_dsi_start_video(struct rcar_mipi_dsi *dsi)
>  	return 0;
>  }
>  
> +static void rcar_mipi_dsi_stop_video(struct rcar_mipi_dsi *dsi)
> +{
> +	u32 status;
> +	int ret;
> +
> +	/* Disable transmission in video mode. */
> +	rcar_mipi_dsi_clr(dsi, TXVMCR, TXVMCR_EN_VIDEO);
> +
> +	ret = read_poll_timeout(rcar_mipi_dsi_read, status,
> +				!(status & TXVMSR_ACT),
> +				2000, 100000, false, dsi, TXVMSR);
> +	if (ret < 0) {
> +		dev_err(dsi->dev, "Failed to disable video transmission\n");
> +		return;
> +	}
> +
> +	/* Assert video FIFO clear. */
> +	rcar_mipi_dsi_set(dsi, TXVMCR, TXVMCR_VFCLR);
> +
> +	ret = read_poll_timeout(rcar_mipi_dsi_read, status,
> +				!(status & TXVMSR_VFRDY),
> +				2000, 100000, false, dsi, TXVMSR);
> +	if (ret < 0) {
> +		dev_err(dsi->dev, "Failed to assert video FIFO clear\n");
> +		return;
> +	}
> +}
> +
>  /* -----------------------------------------------------------------------------
>   * Bridge
>   */
> @@ -601,6 +629,7 @@ static void rcar_mipi_dsi_atomic_disable(struct drm_bridge *bridge,
>  {
>  	struct rcar_mipi_dsi *dsi = bridge_to_rcar_mipi_dsi(bridge);
>  
> +	rcar_mipi_dsi_stop_video(dsi);
>  	rcar_mipi_dsi_shutdown(dsi);
>  	rcar_mipi_dsi_clk_disable(dsi);
>  }

-- 
Regards,

Laurent Pinchart