sm501fb: Ensure panel interface is not tristated when setup

When we setup the panel interface whilst configuring the
framebuffer, we should ensure the panel interface is not
in tristate, in case the bootloader or previous setup has
not enabled it.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/video/sm501fb.c b/drivers/video/sm501fb.c
index d97edd7a6e41..1be95a68d696 100644
--- a/drivers/video/sm501fb.c
+++ b/drivers/video/sm501fb.c
@@ -777,6 +777,11 @@ static int sm501fb_set_par_pnl(struct fb_info *info)
         writel(control, fbi->regs + SM501_DC_PANEL_CONTROL);
         sm501fb_sync_regs(fbi);
 
+        /* ensure the panel interface is not tristated at this point */
+
+        sm501_modify_reg(fbi->dev->parent, SM501_SYSTEM_CONTROL,
+                         0, SM501_SYSCTRL_PANEL_TRISTATE);
+
         /* power the panel up */
         sm501fb_panel_power(fbi, 1);
         return 0;