[PATCH] drm/sun4i: lvds: Invert the LVDS polarity

[PATCH] drm/sun4i: lvds: Invert the LVDS polarity

[Maxime Ripard]

The LVDS controller can invert the polarity / lanes of the LVDS output.
The default polarity causes some issues on some panels.

However, U-Boot has always used the opposite polarity without any reported
issue, and the only currently supported LVDS panel in-tree (the TBS A711)
seems to be able to work with both settings.

Let's just use the same polarity than U-Boot to be more consistent and
hopefully support all the panels.

Cc: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 359b56e43b83..e44635ebd510 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -474,9 +474,7 @@ static void sun4i_tcon0_mode_set_lvds(struct sun4i_tcon *tcon,
 		     SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal * 2) |
 		     SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
 
-	reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0 |
-		SUN4I_TCON0_LVDS_IF_DATA_POL_NORMAL |
-		SUN4I_TCON0_LVDS_IF_CLK_POL_NORMAL;
+	reg = SUN4I_TCON0_LVDS_IF_CLK_SEL_TCON0;
 	if (sun4i_tcon_get_pixel_depth(encoder) == 24)
 		reg |= SUN4I_TCON0_LVDS_IF_BITWIDTH_24BITS;
 	else
-- 
2.26.2

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Re: [PATCH] drm/sun4i: lvds: Invert the LVDS polarity

[Chen-Yu Tsai]

On Sat, Jul 4, 2020 at 9:38 PM Maxime Ripard <maxime@cerno.tech> wrote:
>
> The LVDS controller can invert the polarity / lanes of the LVDS output.
> The default polarity causes some issues on some panels.
>
> However, U-Boot has always used the opposite polarity without any reported
> issue, and the only currently supported LVDS panel in-tree (the TBS A711)
> seems to be able to work with both settings.
>
> Let's just use the same polarity than U-Boot to be more consistent and
> hopefully support all the panels.
>
> Cc: Ondrej Jirman <megous@megous.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>

Reviewed-by: Chen-Yu Tsai <wens@csie.org>
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Re: [PATCH] drm/sun4i: lvds: Invert the LVDS polarity

[Maxime Ripard]

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On Wed, Aug 26, 2020 at 01:13:33AM +0800, Chen-Yu Tsai wrote:
> On Sat, Jul 4, 2020 at 9:38 PM Maxime Ripard <maxime@cerno.tech> wrote:
> >
> > The LVDS controller can invert the polarity / lanes of the LVDS output.
> > The default polarity causes some issues on some panels.
> >
> > However, U-Boot has always used the opposite polarity without any reported
> > issue, and the only currently supported LVDS panel in-tree (the TBS A711)
> > seems to be able to work with both settings.
> >
> > Let's just use the same polarity than U-Boot to be more consistent and
> > hopefully support all the panels.
> >
> > Cc: Ondrej Jirman <megous@megous.com>
> > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> 
> Reviewed-by: Chen-Yu Tsai <wens@csie.org>

Applied, thanks!
Maxime

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