[PATCH 4.16 258/272] drm: rcar-du: lvds: Fix LVDS startup on R-Car Gen3

Greg Kroah-Hartman
2018-05-28T11:16:00Z

From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

[ Upstream commit 796ceb9269626afaed3b4955c40d2c3d7a8c5d01 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/rcar-du/rcar_du_lvdsenc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- 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(s
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(s

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_GEN3(3) | LVDCR1_CHSTBY_GEN3(2) |
@@ -117,7 +120,7 @@ static void rcar_du_lvdsenc_start_gen3(s
* 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;