linux-kernel - Re: [PATCH v2 3/6] clocksource/drivers: atmel-pit: allow unselecting ATMEL

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Message-ID: <20180108092255.7e0f9f07@bbrezillon>
Date:   Mon, 8 Jan 2018 09:22:55 +0100
From:   Boris Brezillon <boris.brezillon@...e-electrons.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/6] clocksource/drivers: atmel-pit: allow
 unselecting ATMEL_PIT

On Mon, 8 Jan 2018 08:23:02 +0100
Daniel Lezcano <daniel.lezcano@...aro.org> wrote:

> On 07/01/2018 19:44, Alexandre Belloni wrote:
> > On 07/01/2018 at 19:07:13 +0100, Daniel Lezcano wrote:  
> >> On 05/01/2018 15:30, Alexandre Belloni wrote:  
> >>> With the new TCB clocksource driver, atmel platforms are now able to boot
> >>> without the PIT driver. Allow unselecting it.
> >>>
> >>> Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
> >>> ---
> >>>  drivers/clocksource/Kconfig | 9 ++++++++-
> >>>  1 file changed, 8 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> >>> index 5609572e0236..55ccfa0ba63b 100644
> >>> --- a/drivers/clocksource/Kconfig
> >>> +++ b/drivers/clocksource/Kconfig
> >>> @@ -381,7 +381,14 @@ config ARMV7M_SYSTICK
> >>>  
> >>>  config ATMEL_PIT
> >>>  	select TIMER_OF if OF
> >>> -	def_bool SOC_AT91SAM9 || SOC_SAMA5
> >>> +	bool "Atmel Periodic Interval Timer (PIT)"
> >>> +	depends on SOC_AT91SAM9 || SOC_SAMA5
> >>> +	default SOC_AT91SAM9 || SOC_SAMA5
> >>> +	help
> >>> +	  Select this to get a clocksource based on the Atmel Periodic Interval
> >>> +	  Timer. It has a relatively low resolution and the TC Block clocksource
> >>> +	  should be preferred.
> >>> +	  It also provides a clock event device.  
> >>
> >> Please conform to the format:
> >>
> >> config ATMEL_PIT
> >> 	bool "Atmel Periodic Interval Timer (PIT)" if COMPILE_TEST
> >> 	select ...
> >> 	help
> >> 	    bla bla
> >>
> >> and select ATMEL_PIT from the platform's Kconfig.
> >>  
> > 
> > Well, the goal is actually to allow people to unselect it so we don't
> > want the platform to select it.  
> 
> Why do you need people to unselect it?

Because we have 2 possible clocksource for atmel platforms: the PIT or
the TCB, if the TCB is selected there's no point in compiling the PIT
driver.

> 
> The goal of the Kconfig here is to be silent except in the case the
> COMPILE_TEST option is set for cross-compilation test coverage.
> 
> We are migrating all these options to this format. Please make it silent.
> 
>