fbdev: sh_mobile_lcdc: Compute clock pattern using divider denominator

The clock divider pattern is computed based on the dot clock register
value which stores the divider denumerator. However, when using a 1:1
divider ratio, the register is programmed with a value that must not be
interpreted as a denominator. This results in a shift left operation
with a value of 32, which produces undefined behaviour.

Compute the clock pattern using the divider denominator, not the dot
clock register value.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/video/sh_mobile_lcdcfb.c b/drivers/video/sh_mobile_lcdcfb.c
index 99656f593de4..2d935db57eac 100644
--- a/drivers/video/sh_mobile_lcdcfb.c
+++ b/drivers/video/sh_mobile_lcdcfb.c
@@ -481,13 +481,15 @@ static int sh_mobile_lcdc_start(struct sh_mobile_lcdc_priv *priv)
                 if (!m)
                         continue;
 
+                /* FIXME: sh7724 can only use 42, 48, 54 and 60 for the divider
+                 * denominator.
+                 */
+                lcdc_write_chan(ch, LDDCKPAT1R, 0);
+                lcdc_write_chan(ch, LDDCKPAT2R, (1 << (m/2)) - 1);
+
                 if (m == 1)
                         m = LDDCKR_MOSEL;
                 tmp |= m << (lcdc_chan_is_sublcd(ch) ? 8 : 0);
-
-                /* FIXME: sh7724 can only use 42, 48, 54 and 60 for the divider denominator */
-                lcdc_write_chan(ch, LDDCKPAT1R, 0);
-                lcdc_write_chan(ch, LDDCKPAT2R, (1 << (m/2)) - 1);
         }
 
         lcdc_write(priv, _LDDCKR, tmp);