[PATCH] drm/bridge: synopsys: dw-mipi-dsi: Fix hcomponent lbcc for burst mode

[Liu Ying]

In order to support burst mode, vendor drivers set lane_mbps higher than
bandwidth through DPI interface.  So, calculate horizontal component lane
byte clock cycle(lbcc) based on lane_mbps instead of pixel clock rate for
burst mode.

Fixes: ac87d23694f4 ("drm/bridge: synopsys: dw-mipi-dsi: Use pixel clock rate 
to calculate lbcc")
Reported-by: Heiko Stübner <he...@sntech.de>
Closes: https://lore.kernel.org/linux-arm-kernel/5979575.UjTJXf6HLC@diego/T/#u
Tested-by: Heiko Stübner <he...@sntech.de> # px30 minievb with xinpeng 
xpp055c272
Signed-off-by: Liu Ying <victor....@nxp.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 8789eca26188..824fb3c65742 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -774,13 +774,19 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct 
dw_mipi_dsi *dsi,
        u32 frac, lbcc, minimum_lbcc;
        int bpp;
 
-       bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
-       if (bpp < 0) {
-               dev_err(dsi->dev, "failed to get bpp\n");
-               return 0;
-       }
+       if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
+               /* lbcc based on lane_mbps */
+               lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+       } else {
+               /* lbcc based on pixel clock rate */
+               bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
+               if (bpp < 0) {
+                       dev_err(dsi->dev, "failed to get bpp\n");
+                       return 0;
+               }
 
-       lbcc = div_u64((u64)hcomponent * mode->clock * bpp, dsi->lanes * 8);
+               lbcc = div_u64((u64)hcomponent * mode->clock * bpp, dsi->lanes 
* 8);
+       }
 
        frac = lbcc % mode->clock;
        lbcc = lbcc / mode->clock;
-- 
2.37.1