Re: [PATCH] m68k/coldfire/pit: set ->min_delta_ticks and ->max_delta_ticks

Greg Ungerer
2017-03-31T01:10:48Z

Hi Nicolai,

On 31/03/17 05:44, Nicolai Stange wrote:
> In preparation for making the clockevents core NTP correction aware,
> all clockevent device drivers must set ->min_delta_ticks and
> ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a
> clockevent device's rate is going to change dynamically and thus, the
> ratio of ns to ticks ceases to stay invariant.
>
> Make the m68k arch's coldfire clockevent driver initialize these fields
> properly.
>
> This patch alone doesn't introduce any change in functionality as the
> clockevents core still looks exclusively at the (untouched) ->min_delta_ns
> and ->max_delta_ns. As soon as this has changed, a followup patch will
> purge the initialization of ->min_delta_ns and ->max_delta_ns from this
> driver.
>
> Signed-off-by: Nicolai Stange <nicstange@gmail.com>

Looks ok to me.

Acked-by: Greg Ungerer <gerg@linux-m68k.org>

Are you pushing this through some other git tree?
Or do you want me to push up to Linus?

Regards
Greg

> ---
>
> Notes:
> This prerequisite patch is part of a larger effort to feed NTP
> corrections into the clockevent devices' frequencies and thus
> avoiding their notion of time to diverge from the system's
> one. If you're interested, the current state of the whole series
> can be found at [1].
>
> If you haven't got any objections and these prerequisites get
> merged by 4.12 everywhere, I'll proceed with the remainder of
> this series in 4.13.
>
> Applicable to next-20170324 as well as to John' Stultz tree [2].
>
> [1]
> git://nicst.de/linux.git cev-freq-adj.v10.fortglx-4.12-time
> https://nicst.de/git/?p=linux.git;a=shortlog;h=refs/heads/cev-freq-adj.v10.fortglx-4.12-time
>
> [2]
> https://git.linaro.org/people/john.stultz/linux.git fortglx/4.12/time
>
> arch/m68k/coldfire/pit.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/m68k/coldfire/pit.c b/arch/m68k/coldfire/pit.c
> index 175553d5b8ed..6c0878018b44 100644
> --- a/arch/m68k/coldfire/pit.c
> +++ b/arch/m68k/coldfire/pit.c
> @@ -149,8 +149,10 @@ void hw_timer_init(irq_handler_t handler)
> cf_pit_clockevent.mult = div_sc(FREQ, NSEC_PER_SEC, 32);
> cf_pit_clockevent.max_delta_ns =
> clockevent_delta2ns(0xFFFF, &cf_pit_clockevent);
> + cf_pit_clockevent.max_delta_ticks = 0xFFFF;
> cf_pit_clockevent.min_delta_ns =
> clockevent_delta2ns(0x3f, &cf_pit_clockevent);
> + cf_pit_clockevent.min_delta_ticks = 0x3f;
> clockevents_register_device(&cf_pit_clockevent);
>
> setup_irq(MCF_IRQ_PIT1, &pit_irq);
>