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video: mxsfb: fix pixel clock polarity

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DISPLAY_FLAGS_PIXDATA_NEGEDGE means the controller drives the data on
pixel clocks falling edge. That is DOTCLK_POL=0 (default) not 1.

The mxsfb-drm driver in the Linux kernel has made the same change and it
remains to this day:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.19-rc2&id=53990e416bb7adaa59d045f325a47f31a11b75ee

I found this was required on an IMX8X SoM.

Without the patch a splash screen displays with aliasing-like jagged edges.

Signed-off-by: Sam Meredith <sam@aandtinstruments.com>
[fabio: Put more information into the commit log]
Signed-off-by: Fabio Estevam <festevam@gmail.com>
This commit is contained in:
Sam Meredith
2025-12-27 18:28:18 -03:00
committed by Fabio Estevam
parent f24a2124d2
commit ff1932daab
1 changed files with 1 additions and 1 deletions
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2
drivers/video/mxsfb.c
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@@ -159,7 +159,7 @@ static void mxs_lcd_init(struct udevice *dev, u32 fb_addr,
vdctrl0 |= LCDIF_VDCTRL0_HSYNC_POL;
if(flags & DISPLAY_FLAGS_VSYNC_HIGH)
vdctrl0 |= LCDIF_VDCTRL0_VSYNC_POL;
if(flags & DISPLAY_FLAGS_PIXDATA_NEGEDGE)
if (flags & DISPLAY_FLAGS_PIXDATA_POSEDGE)
vdctrl0 |= LCDIF_VDCTRL0_DOTCLK_POL;
if(flags & DISPLAY_FLAGS_DE_HIGH)
vdctrl0 |= LCDIF_VDCTRL0_ENABLE_POL;