linux-kernel - Re: [PATCH v4 01/03] clocksource: Add Kconfig entries for CMT, MTU2, TMU and STI

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Message-ID: <CANqRtoSH88L9riQNodA6qBbfvU6DYJc2U-=4KhsjBu-qAjPFjQ@mail.gmail.com>
Date:	Tue, 17 Dec 2013 14:28:13 +0900
From:	Magnus Damm <magnus.damm@...il.com>
To:	Olof Johansson <olof@...om.net>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	Kevin Hilman <khilman@...aro.org>,
	Arnd Bergmann <arnd@...db.de>,
	SH-Linux <linux-sh@...r.kernel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	"Simon Horman [Horms]" <horms@...ge.net.au>,
	John Stultz <john.stultz@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v4 01/03] clocksource: Add Kconfig entries for CMT, MTU2,
 TMU and STI

Hi Olof,

On Mon, Dec 16, 2013 at 2:39 PM, Olof Johansson <olof@...om.net> wrote:
> On Fri, Dec 13, 2013 at 07:12:58PM +0900, Magnus Damm wrote:
>> Hi Olof,
>>
>> On Thu, Dec 12, 2013 at 10:05 AM, Olof Johansson <olof@...om.net> wrote:
>> > Hi,
>> >
>> > A couple of small comments below.
>>
>> Thanks for your feedback!
>>
>> > On Thu, Dec 12, 2013 at 08:56:26AM +0900, Magnus Damm wrote:
>> >> From: Magnus Damm <damm@...nsource.se>
>> >>
>> >> Add Kconfig entries for CMT, MTU2, TMU and STI to
>> >> drivers/clocksource/Kconfig. This will allow us to
>> >> get rid of duplicated entires in architecture code
>> >> such as arch/sh and arch/arm/mach-shmobile.
>> >>
>> >> Signed-off-by: Magnus Damm <damm@...nsource.se>
>> >> ---
>> >>
>> >>  drivers/clocksource/Kconfig |   44 +++++++++++++++++++++++++++++++++++++++++++
>> >>  1 file changed, 44 insertions(+)
>> >>
>> >> --- 0001/drivers/clocksource/Kconfig
>> >> +++ work/drivers/clocksource/Kconfig  2013-12-12 08:41:55.000000000 +0900
>> >> @@ -134,3 +134,47 @@ config VF_PIT_TIMER
>> >>       bool
>> >>       help
>> >>         Support for Period Interrupt Timer on Freescale Vybrid Family SoCs.
>> >> +
>> >> +config SYS_SUPPORTS_CMT
>> >> +        bool
>> >> +
>> >> +config SYS_SUPPORTS_TMU
>> >> +        bool
>> >> +
>> >> +config SYS_SUPPORTS_MTU2
>> >> +        bool
>> >> +
>> >> +config SYS_SUPPORTS_STI
>> >> +        bool
>> >
>> > Maybe a prefix to avoid namespace collissions here?
>>
>> Sure, that is fine with me. I based the ones above on already existing
>> ones used by SH but I don't mind reworking those.
>>
>> How about SYS_SUPPORTS_CLKSRC_xxx?
>
> Oh, I was hoping for something shmobile-specific. Other platforms might have
> some other clock source that they name STI or MTU, for example.

Thanks for the clarification. So how about the following?

SYS_SUPPORTS_SH_CMT
SYS_SUPPORTS_SH_MTU2
SYS_SUPPORTS_SH_TMU
SYS_SUPPORTS_EM_STI

The above match the style of the existing CONFIG_ SH/EM _TIMER_
CMT/MTU2/TMU/STI. Regarding the SH vs EM prefix, the SH ones are
present on arch/sh while EM_STI is only present on Emma Mobile SoCs.

>> >> +config SH_TIMER_CMT
>> >> +     bool "Renesas CMT timer driver" if COMPILE_TEST
>> >> +     default SYS_SUPPORTS_CMT
>> >
>> > It might be useful to have an explicit depends on ARCH_SH || ARCH_SHMOBILE
>> > || COMPILE_TEST on these, just to make it easier for someone reading
>> > the code later on.
>>
>> I have any strong feelings one way or the other about that myself, but
>> I got the impression that John Stultz preferred to not allow manual
>> selection at all, and my compromise here is to allow it only when
>> COMPILE_TEST is selected.
>>
>> Would you be ok to keep it as-is for now? If needed then we can add an
>> incremental patch later to enable more flexible selection.
>
> Yeah, if there's no manual selection at all we might be fine.

Ok, I will keep it as-is then.

Thanks,

/ magnus
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