Re: [PATCH v3 2/2] clocksource: driver for Conexant Digicolor SoC timer

[Daniel Lezcano]

On 01/25/2015 03:46 PM, Baruch Siach wrote:
> Hi Daniel,
>
> On Thu, Jan 22, 2015 at 01:54:39PM +0100, Daniel Lezcano wrote:
> > On 01/21/2015 07:36 AM, Baruch Siach wrote:
> > > + * Based on:
> > > + *	Allwinner SoCs hstimer driver
> >
> > If this is based on the Allwinnner driver, may be you can have a look at the
> > patchset sent by Maxim to make sure your implementation is complete ?
> >
> > https://lkml.org/lkml/2015/1/11/52
>
> Thanks for the tip. I'll take the applicable parts from that series.
>
> [...]
>
> > > +static void __iomem *timer_base;
> > > +static u32 ticks_per_jiffy;
> >
> > Mind to encapsulate those global variables in a structure and use
> > container_of to access those fields like:
> >
> > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/mtk_timer.c#n56
> >
> > ?
>
> The trouble is that the sched_clock callback (digicolor_timer_sched_read)
> needs a static timer_base to find the timer counter. Do you think adding a
> structure is worth it only for ticks_per_jiffy?

Well you will have to define the global variable for this structure. So 
you should be able to access the timer base directly. I agree it is not 
perfect but at least that will encapsulate the code for the clockevents 
side.

> > > +static void digicolor_clkevt_mode(enum clock_event_mode mode,
> > > +				  struct clock_event_device *clk)
> > > +{
> > > +	switch (mode) {
> > > +	case CLOCK_EVT_MODE_PERIODIC:
> > > +		writeb(0, timer_base + CONTROL(TIMER_C));
> >
> > Even if that sounds overkill, please replace '0', '1' with whatever macro
> > name (eg. TIMER_DISABLE/ENABLE).
>
> Will do for the entire file.
>
> [...]
>
> > > +static struct irqaction digicolor_timer_irq = {
> > > +	.name = "digicolor_timerC",
> > > +	.flags = IRQF_TIMER | IRQF_IRQPOLL,
> > > +	.handler = digicolor_timer_interrupt,
> > > +	.dev_id = &digicolor_clockevent,
> > > +};
> >
> > The current trend is to use 'request_irq', so no such structure
> > declaration/initialization is needed.
>
> Thanks. Will do.
>
> > > +	writel(~0, timer_base + COUNT(TIMER_B));
> >
> > s/~0/UINT_MAX/ ?
>
> Ack.
>
> Thanks for reviewing. I'll post an updated series shortly.

Ok, thanks.

  -- Daniel


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