[PATCH v3 08/25] drm/sun4i: sun6i_mipi_dsi: Fix TCON DRQ set bits

[Jagan Teki <jagan@amarulasolutions.com>]

TCON DRQ set bits for non-burst DSI mode can computed via
horizontal front porch instead of front porch + sync timings.

BSP code form BPI-M64-bsp is computing TCON DRQ set bits
for non-burts as
(in linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)

=> panel->lcd_ht -    panel->lcd_x - panel->lcd_hbp
=> (timmings->hor_front_porch + panel->lcd_hbp + panel->lcd_x)
   - panel->lcd_x - panel->hbp
=> timmings->hor_front_porch
=> mode->hsync_start - mode->hdisplay

So, update the DRQ set bits accordingly.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v3:
- Fixed proper commit message
- add tested credit
Changes for v2:
- none

 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 3a1d48bc1996..8d154cf2e6d6 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 	struct mipi_dsi_device *device = dsi->device;
 	u32 val = 0;
 
-	if ((mode->hsync_end - mode->hdisplay) > 20) {
+	if ((mode->hsync_start - mode->hdisplay) > 20) {
 		/* Maaaaaagic */
-		u16 drq = (mode->hsync_end - mode->hdisplay) - 20;
+		u16 drq = (mode->hsync_start - mode->hdisplay) - 20;
 
 		drq *= mipi_dsi_pixel_format_to_bpp(device->format);
 		drq /= 32;
-- 
2.18.0.321.gffc6fa0e3