From: Sekhar Nori Date: Mon, 23 Nov 2009 09:57:15 +0000 (+0530) Subject: davinci: explain CLOCK_TICK_RATE of 27MHz in include/mach/timex.h X-Git-Tag: firefly_0821_release~9833^2~3056^2~30 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5b5052e32dc53e6e76da188c547f14c4e5e35624;p=firefly-linux-kernel-4.4.55.git davinci: explain CLOCK_TICK_RATE of 27MHz in include/mach/timex.h Leave a comment explaining the constant value of 27Mhz used in include/mach/timex.h for all DaVinci platforms. Many of the platforms actually run at 24MHz timer frequency (Eg. EVMs of DM355, DM365 and OMAP-L1). The comment also serves as a porting alert. Signed-off-by: Sekhar Nori Signed-off-by: Kevin Hilman --- diff --git a/arch/arm/mach-davinci/include/mach/timex.h b/arch/arm/mach-davinci/include/mach/timex.h index 52827567841d..9b885298f106 100644 --- a/arch/arm/mach-davinci/include/mach/timex.h +++ b/arch/arm/mach-davinci/include/mach/timex.h @@ -11,7 +11,12 @@ #ifndef __ASM_ARCH_TIMEX_H #define __ASM_ARCH_TIMEX_H -/* The source frequency for the timers is the 27MHz clock */ +/* + * Alert: Not all timers of the DaVinci family run at a frequency of 27MHz, + * but we should be fine as long as CLOCK_TICK_RATE or LATCH (see include/ + * linux/jiffies.h) are not used directly in code. Currently none of the + * code relevant to DaVinci platform depends on these values directly. + */ #define CLOCK_TICK_RATE 27000000 #endif /* __ASM_ARCH_TIMEX_H__ */