From ac87d23694f44af44a98d21dd77016f2756b6b1b Mon Sep 17 00:00:00 2001
From: Liu Ying <victor.liu@nxp.com>
Date: Mon, 21 Aug 2023 11:40:04 +0800
Subject: [PATCH] drm/bridge: synopsys: dw-mipi-dsi: Use pixel clock rate to
calculate lbcc
To get better accuration, use pixel clock rate to calculate lbcc instead of
lane_mbps since the pixel clock rate is in KHz while lane_mbps is in MHz.
Without this, distorted image can be seen on a HDMI monitor connected with
i.MX93 11x11 EVK through ADV7535 DSI to HDMI bridge in 1920x1080p@60 video
mode.
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230821034008.3876938-6-victor.liu@nxp.com
---
drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 40d699428b1bd..b21ad4ea9dca3 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -12,6 +12,7 @@
#include <linux/component.h>
#include <linux/debugfs.h>
#include <linux/iopoll.h>
+#include <linux/math64.h>
#include <linux/media-bus-format.h>
#include <linux/module.h>
#include <linux/platform_device.h>
@@ -764,8 +765,15 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
u32 hcomponent)
{
u32 frac, lbcc;
+ int bpp;
- lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+ 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);
frac = lbcc % mode->clock;
lbcc = lbcc / mode->clock;
--
GitLab