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authorDeepak Saxena <dsaxena@plexity.net>2005-08-23 13:30:29 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-08-23 20:06:33 -0700
commit9138dccbb9f39f12474554ef93dcc24de2e9c8f6 (patch)
treec7e606155b97f5a7e0a8808b1e2cbf37ea0162ac
parentd10689b68aff7b48e3de1a3f7fcd6567bd2905af (diff)
[PATCH] Fix IXP4xx CLOCK_TICK_RATE
As pointed out in the following thread, the CLOCK_TICK_RATE setting for IXP4xx is incorrect b/c the HW ignores the lowest 2 bits of the LATCH value. http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2005-August/030950.html Tnx to George Anziger and Egil Hjelmeland for finding the issue. Signed-off-by: Deepak Saxena <dsaxena@plexity.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/asm-arm/arch-ixp4xx/timex.h6
1 files changed, 4 insertions, 2 deletions
diff --git a/include/asm-arm/arch-ixp4xx/timex.h b/include/asm-arm/arch-ixp4xx/timex.h
index 38c9d77d372..3745e35cc03 100644
--- a/include/asm-arm/arch-ixp4xx/timex.h
+++ b/include/asm-arm/arch-ixp4xx/timex.h
@@ -7,7 +7,9 @@
/*
* We use IXP425 General purpose timer for our timer needs, it runs at
- * 66.66... MHz
+ * 66.66... MHz. We do a convulted calculation of CLOCK_TICK_RATE b/c the
+ * timer register ignores the bottom 2 bits of the LATCH value.
*/
-#define CLOCK_TICK_RATE (66666666)
+#define FREQ 66666666
+#define CLOCK_TICK_RATE (((FREQ / HZ & ~IXP4XX_OST_RELOAD_MASK) + 1) * HZ)