Re: [RFC PATCH 02/10] clockevents/drivers: add MPS2 Timer driver

Vladimir Murzin
2015-11-25T14:51:06Z

Hi Daniel,

Thanks for you review, I agree on all concerns raised and address them
in the next version. Just some points to confirm below (I left only
relevant parts).

>> +static irqreturn_t mps2_timer_interrupt(int irq, void *dev_id)
>> +{
>> + struct clockevent_mps2 *ce = dev_id;
>> + u32 status = readl(ce->reg + TIMER_INT);
>> +
>> + if (!status)
>> + return IRQ_NONE;
>
> Why that could happen ? Add a comment.
>

Sort of defensive programming, I never seen it happens, but just in case
of spurious interrupts... Do you prefer to get rid of this check or

/* spurious interrupt? */
if (!status)
return IRQ_NONE;

would be fine to you?

>> +}
>> +
>> +static void __init mps2_timer_init(struct device_node *np)
>> +{
>> + static int clksrc;
>> +
>> + if (!clksrc && !mps2_clocksource_init(np))
>> + clksrc = 1;
>> + else
>> + mps2_clockevents_init(np);
>
> That assumes the clocksource is defined before the clockevents in the
> DT. If it is not the case, the mps2_clocksource_init will fail (and spit
> errors) and mps2_clockevents_init() won't be called.
>

Does following (stolen from efm32) look better to you?

static void __init mps2_timer_init(struct device_node *np)
{
static int has_clocksource, has_clockevent;
int ret;

if (!has_clocksource) {
ret = mps2_clocksource_init(np);
if (!ret) {
has_clocksource = 1;
return;
}
}

if (!has_clockevent) {
ret = mps2_clockevent_init(np);
if (!ret) {
has_clockevent = 1;
return;
}
}
}

Thanks
Vladimir

>> +}
>> +
>> +CLOCKSOURCE_OF_DECLARE(mps2_timer, "arm,mps2-timer", mps2_timer_init);
>>
>
>