[PATCH v4 15/17] drm/bridge: cdns-dsi: Fix event mode

[Jayesh Choudhary]

Hello Tomi,

On 18/06/25 15:29, Tomi Valkeinen wrote:
> The timings calculation gets it wrong for DSI event mode, resulting in
> too large hbp value. Fix the issue by taking into account the
> pulse/event mode difference.
> 
> Tested-by: Parth Pancholi <parth.pancholi at toradex.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>

Reviewed-by: Jayesh Choudhary <j-choudhary at ti.com>

> ---
>   drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c | 31 +++++++++++++++++---------
>   1 file changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> index 07f8d5f5c2aa..3bc4d011b4c6 100644
> --- a/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> +++ b/drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c
> @@ -418,7 +418,8 @@
>   #define DSI_OUTPUT_PORT			0
>   #define DSI_INPUT_PORT(inputid)		(1 + (inputid))
>   
> -#define DSI_HBP_FRAME_OVERHEAD		12
> +#define DSI_HBP_FRAME_PULSE_OVERHEAD	12
> +#define DSI_HBP_FRAME_EVENT_OVERHEAD	16
>   #define DSI_HSA_FRAME_OVERHEAD		14
>   #define DSI_HFP_FRAME_OVERHEAD		6
>   #define DSI_HSS_VSS_VSE_FRAME_OVERHEAD	4
> @@ -487,23 +488,31 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
>   
>   	bpp = mipi_dsi_pixel_format_to_bpp(output->dev->format);
>   
> -	dsi_cfg->hbp = dpi_to_dsi_timing(dpi_hbp + (sync_pulse ? 0 : dpi_hsa),
> -					 bpp, DSI_HBP_FRAME_OVERHEAD);
> +	if (sync_pulse) {
> +		dsi_cfg->hbp = dpi_to_dsi_timing(dpi_hbp, bpp,
> +						 DSI_HBP_FRAME_PULSE_OVERHEAD);
>   
> -	if (sync_pulse)
> -		dsi_cfg->hsa =
> -			dpi_to_dsi_timing(dpi_hsa, bpp, DSI_HSA_FRAME_OVERHEAD);
> +		dsi_cfg->hsa = dpi_to_dsi_timing(dpi_hsa, bpp,
> +						 DSI_HSA_FRAME_OVERHEAD);
> +	} else {
> +		dsi_cfg->hbp = dpi_to_dsi_timing(dpi_hbp + dpi_hsa, bpp,
> +						 DSI_HBP_FRAME_EVENT_OVERHEAD);
> +
> +		dsi_cfg->hsa = 0;
> +	}
>   
>   	dsi_cfg->hact = dpi_to_dsi_timing(dpi_hact, bpp, 0);
>   
>   	dsi_cfg->hfp = dpi_to_dsi_timing(dpi_hfp, bpp, DSI_HFP_FRAME_OVERHEAD);
>   
> -	dsi_cfg->htotal = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
> -	if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> -		dsi_cfg->htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> +	dsi_cfg->htotal = dsi_cfg->hact + dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
>   
> -	dsi_cfg->htotal += dsi_cfg->hact;
> -	dsi_cfg->htotal += dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
> +	if (sync_pulse) {
> +		dsi_cfg->htotal += dsi_cfg->hbp + DSI_HBP_FRAME_PULSE_OVERHEAD;
> +		dsi_cfg->htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
> +	} else {
> +		dsi_cfg->htotal += dsi_cfg->hbp + DSI_HBP_FRAME_EVENT_OVERHEAD;
> +	}
>   
>   	return 0;
>   }
>