cirrusfb: simplify clock calculation
Krzysztof Helt [Thu, 16 Oct 2008 05:03:36 +0000 (22:03 -0700)]
Simplify clock calculation.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/cirrusfb.c

index 09f4214..dfd12a2 100644 (file)
@@ -3075,38 +3075,36 @@ static void bestclock(long freq, long *best, long *nom,
        f = freq * 10;
 
        for (n = 32; n < 128; n++) {
+               int s = 0;
+
                d = (143181 * n) / f;
                if ((d >= 7) && (d <= 63)) {
-                       if (d > 31)
-                               d = (d / 2) * 2;
-                       h = (14318 * n) / d;
+                       int temp = d;
+
+                       if (temp > 31) {
+                               s = 1;
+                               temp >>= 1;
+                       }
+                       h = ((14318 * n) / temp) >> s;
                        if (abs(h - freq) < abs(*best - freq)) {
                                *best = h;
                                *nom = n;
-                               if (d < 32) {
-                                       *den = d;
-                                       *div = 0;
-                               } else {
-                                       *den = d / 2;
-                                       *div = 1;
-                               }
+                               *den = temp;
+                               *div = s;
                        }
                }
-               d = DIV_ROUND_UP(143181 * n, f);
+               d++;
                if ((d >= 7) && (d <= 63)) {
-                       if (d > 31)
-                               d = (d / 2) * 2;
-                       h = (14318 * n) / d;
+                       if (d > 31) {
+                               s = 1;
+                               d >>= 1;
+                       }
+                       h = ((14318 * n) / d) >> s;
                        if (abs(h - freq) < abs(*best - freq)) {
                                *best = h;
                                *nom = n;
-                               if (d < 32) {
-                                       *den = d;
-                                       *div = 0;
-                               } else {
-                                       *den = d / 2;
-                                       *div = 1;
-                               }
+                               *den = d;
+                               *div = s;
                        }
                }
        }