17.06.2019 13:51, Jon Hunter пишет:
>
> On 14/06/2019 17:45, Dmitry Osipenko wrote:
>> 14.06.2019 18:48, Jon Hunter пишет:
>>>
>>> On 10/06/2019 17:43, Dmitry Osipenko wrote:
>>>> The of_clk structure has a period field that is set up initially by
>>>> timer_of_clk_init(), that period value need to be adjusted for a case of
>>>> TIMER1-9 that are running at a fixed rate that doesn't match the clock's
>>>> rate. Note that the period value is currently used only by some of the
>>>> clocksource drivers internally and hence this is just a minor cleanup
>>>> change that doesn't fix anything.
>>>>
>>>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>>>> ---
>>>> drivers/clocksource/timer-tegra.c | 5 +++--
>>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/clocksource/timer-tegra.c b/drivers/clocksource/timer-tegra.c
>>>> index 810b4e7435cf..646b3530c2d2 100644
>>>> --- a/drivers/clocksource/timer-tegra.c
>>>> +++ b/drivers/clocksource/timer-tegra.c
>>>> @@ -71,9 +71,9 @@ static int tegra_timer_shutdown(struct clock_event_device *evt)
>>>> static int tegra_timer_set_periodic(struct clock_event_device *evt)
>>>> {
>>>> void __iomem *reg_base = timer_of_base(to_timer_of(evt));
>>>> + unsigned long period = timer_of_period(to_timer_of(evt));
>>>>
>>>> - writel_relaxed(TIMER_PTV_EN | TIMER_PTV_PER |
>>>> - ((timer_of_rate(to_timer_of(evt)) / HZ) - 1),
>>>> + writel_relaxed(TIMER_PTV_EN | TIMER_PTV_PER | (period - 1),
>>>> reg_base + TIMER_PTV);
>>>>
>>>> return 0;
>>>> @@ -297,6 +297,7 @@ static int __init tegra_init_timer(struct device_node *np, bool tegra20,
>>>> cpu_to->clkevt.rating = rating;
>>>> cpu_to->clkevt.cpumask = cpumask_of(cpu);
>>>> cpu_to->of_base.base = timer_reg_base + base;
>>>> + cpu_to->of_clk.period = DIV_ROUND_UP(rate, HZ);
>>>
>>> Any reason you made this a round-up?
>>
>> That's what timer_of_clk_init() does, I assume it should be a more correct variant.
>
> Sounds to me like this should be 2 patches, because you are changing the
> value. This is not just purely cleanup IMO.
Indeed, that could be at least mentioned in the commit message. Probably I just
assumed that this is such a minor change that not worth anything. A hundred of
microseconds is hardly noticeable.
I'm not really sure if this really worth a re-spin at this point. Jon, are you insisting?
Also, I now see that some drivers use DIV_ROUND_CLOSEST(), maybe it will be even
better? Not sure.. given that this is still a microseconds difference.
