Sansa AMS: Revert r21177 : the timer frequency is used by the user timer (example: metronome will be twice too fast)

Instead use a private KERNEL_TIMER_FREQ define which is dependant on HAVE_SCROLLWHEEL
Comment that call_tick_tasks() will read the scrollwheel
Remove the unneeded volatile type qualifier from poll_scrollwheel

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21187 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 12 insertions, 4 deletions

diff --git a/firmware/target/arm/as3525/kernel-as3525.c b/firmware/target/arm/as3525/kernel-as3525.c
index 0f907f61e3..d8f0e23d30 100644
--- a/firmware/target/arm/as3525/kernel-as3525.c
+++ b/firmware/target/arm/as3525/kernel-as3525.c
@@ -25,18 +25,26 @@
 #include "timer-target.h"
 
 #ifdef HAVE_SCROLLWHEEL
+/* let the timer interrupt twice as often for the scrollwheel polling */
+#define KERNEL_TIMER_FREQ (TIMER_FREQ/2)
+#else
+#define KERNEL_TIMER_FREQ TIMER_FREQ
+#endif
+
+#ifdef HAVE_SCROLLWHEEL
 #include "button-target.h"
 /* The scrollwheel is polled every 5 ms (the tick tasks only every 10) */
-static volatile int poll_scrollwheel = 0;
+static int poll_scrollwheel = 0;
 
 void INT_TIMER2(void)
 {
     if (!poll_scrollwheel)
-        call_tick_tasks();  /* Run through the list of tick tasks */
+        call_tick_tasks();      /* Run through the list of tick tasks
+                                 * (that includes reading the scrollwheel) */
     else
     {
         if (!button_hold())
-            button_read_dbop();
+            button_read_dbop(); /* Read the scrollwheel */
     }
 
     poll_scrollwheel ^= 1;
@@ -55,7 +63,7 @@ void tick_start(unsigned int interval_in_ms)
 {
     int phi = 0;                            /* prescaler bits */
     int prescale = 1;
-    int cycles = TIMER_FREQ / 1000 * interval_in_ms;
+    int cycles = KERNEL_TIMER_FREQ / 1000 * interval_in_ms;
 
     while(cycles > 0x10000)
     {