[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 <heiko at sntech.de>
Closes: https://lore.kernel.org/linux-arm-kernel/5979575.UjTJXf6HLC@diego/T/#u
Tested-by: Heiko Stübner <heiko at sntech.de> # px30 minievb with xinpeng xpp055c272
Signed-off-by: Liu Ying <victor.liu at 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