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Subject[PATCH v8 1/8] drm/sun4i: sun6i_mipi_dsi: Fix VBP size calculation
Date
The horizontal and vertical back porch calculation in BSP
code is simply following the Linux drm comment diagram, in
include/drm/drm_modes.h which is

[hv]back porch = [hv]total - [hv]sync_end

BSP code form BPI-M64-bsp is calculating vertical back porch as
(from linux-sunxi/drivers/video/sunxi/disp2/disp/de/disp_lcd.c)

timmings->ver_sync_time= panel_info->lcd_vspw;
timmings->ver_back_porch= panel_info->lcd_vbp-panel_info->lcd_vspw;

vbp = panel->lcd_vbp;
vspw = panel->lcd_vspw;
dsi_dev[sel]->dsi_basic_size0.bits.vbp = vbp-vspw;
dsi_dev[sel]->dsi_basic_size0.bits.vbp = panel->lcd_vbp - panel->lcd_vspw;
=> timmings->ver_back_porch + panel_info->lcd_vspw - panel_info->lcd_vspw
=> timmings->ver_back_porch
=> mode->vtotal - mode->end

Which evatually same as mode->vtotal - mode->vsync_end so fix the VBP
value in SUN6I_DSI_BASIC_SIZE0_VBP

On the information note, existing SUN6I_DSI_BASIC_SIZE0_VSA is proper
value.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
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 318994cd1b85..d70a8c43a4b8 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -526,8 +526,8 @@ static void sun6i_dsi_setup_timings(struct sun6i_dsi *dsi,
regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE0_REG,
SUN6I_DSI_BASIC_SIZE0_VSA(mode->vsync_end -
mode->vsync_start) |
- SUN6I_DSI_BASIC_SIZE0_VBP(mode->vsync_start -
- mode->vdisplay));
+ SUN6I_DSI_BASIC_SIZE0_VBP(mode->vtotal -
+ mode->vsync_end));

regmap_write(dsi->regs, SUN6I_DSI_BASIC_SIZE1_REG,
SUN6I_DSI_BASIC_SIZE1_VACT(mode->vdisplay) |
--
2.18.0.321.gffc6fa0e3
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