Re: [PATCH v2 19/29] nios2: Time keeping

Arnd Bergmann
2014-07-21T10:51:50Z

On Monday 21 July 2014 18:07:02 Ley Foon Tan wrote:
> >
> >> +#ifndef _ASM_NIOS2_TIMEX_H
> >> +#define _ASM_NIOS2_TIMEX_H
> >> +
> >> +/* Supply dummy tick-rate. Real value will be read from devicetree */
> >> +#define CLOCK_TICK_RATE (HZ * 100000UL)
> >> +
> >> +#include <asm-generic/timex.h>
> >> +
> >> +#endif
> >
> > CLOCK_TICK_RATE is no longer used anywhere, no need for this file.
>
> I found jiffies.h still using this define. Can we still remove this?
> In include/linux/jiffies.h:
> #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */
>

Ah, I thought we had killed off LATCH, but at least it is only used
on architecture specific code, and only in two files:

arch/x86/kernel/apm_32.c: outb_p(LATCH & 0xff, PIT_CH0); /* LSB */
arch/unicore32/kernel/time.c: writel(readl(OST_OSMR0) - LATCH, OST_OSCR);

We could decide to move the LATCH definition into those two files to
remove it from common code, but it doesn't really hurt otherwise,
and everything works fine if you don't define CLOCK_TICK_RATE on
architectures that don't need LATCH or CLOCK_TICK_RATE in their
architecture-specific code.

Arnd