drm: rcar-du: lvds: Fix LVDS startup on R-Car Gen3

According to the latest revisions of the R-Car Gen3 manual, the LVDS mode
must be set before the LVDS I/O pins are enabled, not after -- fix the
Gen3 LVDS startup sequence accordingly.

Fixes: e947eccbeba4 ("drm: rcar-du: Add support for LVDS mode selection")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[Updated comment in rcar_du_lvdsenc_start_gen3()]
[Moved Gen2 startup comment update to separate commit]
[Fixed =| typo]
Tested-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c b/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
index dcffd3b59b69..01ef0f728e94 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c
@@ -95,7 +95,7 @@ static void rcar_du_lvdsenc_start_gen3(struct rcar_du_lvdsenc *lvds,
         u32 lvdcr0;
         u32 pllcr;
 
-        /* PLL clock configuration */
+        /* Set the PLL clock configuration and LVDS mode. */
         if (freq < 42000)
                 pllcr = LVDPLLCR_PLLDIVCNT_42M;
         else if (freq < 85000)
@@ -107,6 +107,9 @@ static void rcar_du_lvdsenc_start_gen3(struct rcar_du_lvdsenc *lvds,
 
         rcar_lvds_write(lvds, LVDPLLCR, pllcr);
 
+        lvdcr0 = lvds->mode << LVDCR0_LVMD_SHIFT;
+        rcar_lvds_write(lvds, LVDCR0, lvdcr0);
+
         /* Turn all the channels on. */
         rcar_lvds_write(lvds, LVDCR1,
                         LVDCR1_CHSTBY(3) | LVDCR1_CHSTBY(2) |
@@ -116,7 +119,7 @@ static void rcar_du_lvdsenc_start_gen3(struct rcar_du_lvdsenc *lvds,
          * Turn the PLL on, set it to LVDS normal mode, wait for the startup
          * delay and turn the output on.
          */
-        lvdcr0 = (lvds->mode << LVDCR0_LVMD_SHIFT) | LVDCR0_PLLON;
+        lvdcr0 |= LVDCR0_PLLON;
         rcar_lvds_write(lvds, LVDCR0, lvdcr0);
 
         lvdcr0 |= LVDCR0_PWD;