From: Ondrej Jirman <megous@megous.com>
Date: Thu, 22 Feb 2018 17:12:17 +0100
Subject: drm/sun4i: Enable the output on the pins (tcon0)
Git-commit: 80b79e31c4195731464d96716f15716f38a555eb
Patch-mainline: v4.16-rc4
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

I noticed that with 4.16-rc1 LVDS output on A83T based TBS A711 tablet doesn't
work (there's output but it's garbled). I compared some older patches for LVDS
support with the mainlined ones and this change is missing from mainline Linux.

I don't know what the register does exactly and the harcoded register value
doesn't inspire much confidence that it will work in a general case, so I'm
sending this RFC.

This patch fixes the issue on A83T.

Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180222161217.23904-1-megous@megous.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/sun4i/sun4i_tcon.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -335,6 +335,9 @@ static void sun4i_tcon0_mode_set_lvds(st
 	regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
 			   SUN4I_TCON_GCTL_IOMAP_MASK,
 			   SUN4I_TCON_GCTL_IOMAP_TCON0);
+
+	/* Enable the output on the pins */
+	regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, 0xe0000000);
 }
 
 static void sun4i_tcon0_mode_set_rgb(struct sun4i_tcon *tcon,