Re: [PATCH v2 04/18] clocksource: Add ARM System timer driver

Paul Bolle
2015-02-20T21:48:35Z

On Fri, 2015-02-20 at 20:54 +0100, Uwe Kleine-König wrote:
> On Fri, Feb 20, 2015 at 07:01:03PM +0100, Maxime Coquelin wrote:
> > This patch adds clocksource support for ARMv7-M's System timer,
> > also known as SysTick.
> >
> > Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
> > ---
> > drivers/clocksource/Kconfig | 7 ++++
> > drivers/clocksource/Makefile | 1 +
> > drivers/clocksource/armv7m_systick.c | 78 ++++++++++++++++++++++++++++++++++++
> > 3 files changed, 86 insertions(+)
> > create mode 100644 drivers/clocksource/armv7m_systick.c
> >
> > diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> > index fc01ec2..fb6011e 100644
> > --- a/drivers/clocksource/Kconfig
> > +++ b/drivers/clocksource/Kconfig
> > @@ -124,6 +124,13 @@ config CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
> > help
> > Use ARM global timer clock source as sched_clock
> >
> > +config ARMV7M_SYSTICK
> > + bool
> I assume this symbol is enabled later in the series.

Yes, I noticed it was selected in 14/18 ("ARM: Add STM32 family
machine").

> Would it make sense
> to allow enabing the symbol for compile test coverage?
>
> > + select CLKSRC_OF if OF
> What happens if ARMV7M_SYSTICK=y but OF=n? Doesn't the driver fail to
> compile?
>
> > + select CLKSRC_MMIO
> > + help
> > + This options enables support for the ARMv7M system timer unit
> the right spelling is ARMv7-M.

This Kconfig entry has no prompt, so no one is going to see this text
during make *config. Perhaps this should be made a comment. In that case
the right spelling should still be used.

Thanks,

Paul Bolle