linux-kernel - Re: [PATCH v8 09/16] clockevents/drivers: Add STM32 Timer driver

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Date:	Tue, 19 May 2015 11:44:03 +0200
From:	Maxime Coquelin <mcoquelin.stm32@...il.com>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>,
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Subject: Re: [PATCH v8 09/16] clockevents/drivers: Add STM32 Timer driver

2015-05-19 11:06 GMT+02:00 Daniel Lezcano <daniel.lezcano@...aro.org>:
> On 05/19/2015 10:55 AM, Maxime Coquelin wrote:
>>
>> 2015-05-19 10:16 GMT+02:00 Daniel Lezcano <daniel.lezcano@...aro.org>:
>>>
>>> On 05/18/2015 04:03 PM, Maxime Coquelin wrote:
>>>>
>>>>
>>>> 2015-05-18 15:10 GMT+02:00 Daniel Lezcano <daniel.lezcano@...aro.org>:
>>>>>
>>>>>
>>>>> On 05/09/2015 09:53 AM, Maxime Coquelin wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> STM32 MCUs feature 16 and 32 bits general purpose timers with
>>>>>> prescalers.
>>>>>> The drivers detects whether the time is 16 or 32 bits, and applies a
>>>>>> 1024 prescaler value if it is 16 bits.
>>>>>>
>>>>>> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>>>>>> Tested-by: Chanwoo Choi <cw00.choi@...sung.com>
>>>>>> Signed-off-by: Maxime Coquelin <mcoquelin.stm32@...il.com>
>>>>>> ---
>>>>>>     drivers/clocksource/Kconfig       |   8 ++
>>>>>>     drivers/clocksource/Makefile      |   1 +
>>>>>>     drivers/clocksource/timer-stm32.c | 184
>>>>>> ++++++++++++++++++++++++++++++++++++++
>>>>>>     3 files changed, 193 insertions(+)
>>>>>>     create mode 100644 drivers/clocksource/timer-stm32.c
>>>>>>
>>>>>> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
>>>>>> index bf9364c..2443520 100644
>>>>>> --- a/drivers/clocksource/Kconfig
>>>>>> +++ b/drivers/clocksource/Kconfig
>>>>>> @@ -106,6 +106,14 @@ config CLKSRC_EFM32
>>>>>>             Support to use the timers of EFM32 SoCs as clock source
>>>>>> and
>>>>>> clock
>>>>>>             event device.
>>>>>>
>>>>>> +config CLKSRC_STM32
>>>>>> +       bool "Clocksource for STM32 SoCs" if !ARCH_STM32
>>>>>> +       depends on OF && ARM && (ARCH_STM32 || COMPILE_TEST)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Are the interactive bool and the 'COMPILE_TEST' necessary ?
>>>>>
>>>>
>>>> The interactive bool is necessary if we want to be able to
>>>> select/deselect it in COMPILE_TEST configuration.
>>>> And personnaly, I think COMPILE_TEST use makes sense.
>>>>
>>>> Note that other timer drivers are doing the same thing today
>>>> (CLKSRC_EFM32, SH_TIMER_CMT, EM_TIMER_STI...).
>>>>
>>>> Do you have a specific concern regarding COMPILE_TEST?
>>>
>>>
>>>
>>> Actually, we try to keep the timer selection non-interactive and let the
>>> platform's Kconfig to select the timer.
>>
>>
>> Ok.
>>
>>>
>>> I like when the code is consistent. The COMPILE_TEST was introduced and
>>> created a precedence. I would like to get rid of the interactive timer
>>> selection but I did not have time to go through this yet.
>>
>>
>> Indeed, consistency is important.
>> On my side, I don't have a strong opinion regarding the COMPILE_TEST
>> thing.
>> IMHO, it is more a subsystem's maintainer choice.
>>
>> So, if as a maintainer you don't use it and prefer not supporting it,
>> I'm fine to provide you a new version without COMPILE_TEST.
>> Doing that, the interactive selection will disappear too.
>>
>> I can provide you a new version this evenning.
>
>
> Ok, great.

Is the below Kconfig entry fine for you?

config CLKSRC_STM32
    def_bool y if ARCH_STM32
    select CLKSRC_MMIO

Best regards,
Maxime


>
> Thanks
>   -- Daniel
>
>
>>>
>>>
>>>
>>> --
>>>   <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>>>
>>> Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
>>> <http://twitter.com/#!/linaroorg> Twitter |
>>> <http://www.linaro.org/linaro-blog/> Blog
>>>
>
>
> --
>  <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
>
> Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
> <http://twitter.com/#!/linaroorg> Twitter |
> <http://www.linaro.org/linaro-blog/> Blog
>
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