linux-kernel - Re: [PATCH v3 3/5] ARM: Exynos: switch to using generic cpufreq driver for Exynos4x12

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Date:	Tue, 04 Aug 2015 09:43:41 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc:	Viresh Kumar <viresh.kumar@...aro.org>,
	Thomas Abraham <thomas.ab@...sung.com>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Michael Turquette <mturquette@...libre.com>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Kukjin Kim <kgene@...nel.org>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Lukasz Majewski <l.majewski@...sung.com>,
	Heiko Stuebner <heiko@...ech.de>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Kevin Hilman <khilman@...aro.org>,
	Javier Martinez Canillas <javier@...hile0.org>,
	Tobias Jakobi <tjakobi@...h.uni-bielefeld.de>,
	Anand Moon <linux.amoon@...il.com>,
	linux-samsung-soc@...r.kernel.org, linux-clk@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Javier Martinez Canillas <javier@....samsung.com>,
	Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <edubezval@...il.com>
Subject: Re: [PATCH v3 3/5] ARM: Exynos: switch to using generic cpufreq driver
 for Exynos4x12

On 03.08.2015 22:55, Bartlomiej Zolnierkiewicz wrote:
> 
> Hi,
> 
> On Monday, August 03, 2015 08:15:13 PM Krzysztof Kozlowski wrote:
>> W dniu 03.08.2015 o 19:36, Bartlomiej Zolnierkiewicz pisze:
>>> On Monday, August 03, 2015 03:59:26 PM Viresh Kumar wrote:
>>>> On 03-08-15, 12:17, Bartlomiej Zolnierkiewicz wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> On Saturday, August 01, 2015 04:47:21 PM Viresh Kumar wrote:
>>>>>> On 31-07-15, 20:49, Bartlomiej Zolnierkiewicz wrote:
>>>>>>> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
>>>>>>> index 659879a..bf6d596 100644
>>>>>>> --- a/drivers/cpufreq/Kconfig
>>>>>>> +++ b/drivers/cpufreq/Kconfig
>>>>>>> @@ -191,6 +191,7 @@ config CPUFREQ_DT
>>>>>>>  	# if CPU_THERMAL is on and THERMAL=m, CPUFREQ_DT cannot be =y:
>>>>>>>  	depends on !CPU_THERMAL || THERMAL
>>>>>>>  	select PM_OPP
>>>>>>> +	select EXYNOS_THERMAL if ARCH_EXYNOS
>>>>>>>  	help
>>>>>>>  	  This adds a generic DT based cpufreq driver for frequency management.
>>>>>>>  	  It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
>>>>>>
>>>>>> No, we shouldn't pollute generic Kconfig options with platform specific stuff.
>>>>>
>>>>> The old code depended on this.  You couldn't enable boost support
>>>>> without enabling thermal support (ARM_EXYNOS_CPU_FREQ_BOOST_SW
>>>>> config option selected EXYNOS_THERMAL).
>>>>>
>>>>>> Why don't you enable thermal in your .config?
>>>>>
>>>>> It is enabled in exynos_defconfig but without the above change it
>>>>> can disabled manually which is something that we don't want.
>>>>
>>>> You are not getting it. I am not asking you to not select thermal, but
>>>> to select it from within your architecture Kconfig option if you want.
>>>
>>> OK.  Krzysztof/Kukjin do you agree with selecting EXYNOS_THERMAL
>>> from ARCH_EXYNOS in the platform code?
>>
>> I agree, with your explanation it seems good. Can you just add this
>> justification to the commit message?
> 
> Updated patch below (I'm not resending the whole series as all other
> patches remain unchanged).
> 
>>>
>>>> Over that, thermal is really an option, not a dependency. So, if
>>>> someone manually disables it, its his problem not yours :)
>>>
>>> I would really like it to be dependency not an option (+ I think
>>> that ideally it should be checked at runtime, IOW we should be
>>> checking from cpufreq-dt driver if the thermal support is enabled
>>> before enabling boost support).
>>
>> That would be the best. It is fine with me if you want to do this in
>> consecutive patches (after applying patch selecting/depending on it in
>> mach-exynos code).
> 
> ---------------------8<-------------------
> 
>>>From 2595b5e6164a2d1b76626e14302b148b7af5e050 Mon Sep 17 00:00:00 2001
> From: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> Date: Mon, 3 Aug 2015 15:49:06 +0200
> Subject: [PATCH] ARM: Exynos: switch to using generic cpufreq driver for
>  Exynos4x12
> 
> The new CPU clock type allows the use of generic CPUfreq driver.
> Switch Exynos4x12 to using generic cpufreq driver.
> 
> Previously (when exynos-cpufreq driver was used with boost
> functionality) ARM_EXYNOS_CPU_FREQ_BOOST_SW config option
> (which enabled boost functionality) selected EXYNOS_THERMAL
> one.  After switching Exynos4x12 platforms to use cpufreq-dt
> driver boost support is enabled in the cpufreq-dt driver
> itself (because there are turbo OPPs defined in the board's
> DTS file).  However we still would like to allow enabling
> boost support only if thermal support is also enabled for
> Exynos platforms.  To achieve this make ARCH_EXYNOS config
> option select THERMAL and EXYNOS_THERMAL ones.
> 
> Please also note that the switch to use the generic cpufreq-dt
> driver fixes the minor issue present with the old code (support
> for 'boost' mode in the exynos-cpufreq driver was enabled for
> all supported SoCs even though 'boost' frequency was provided
> only for Exynos4x12 ones).
> 
> Cc: Tomasz Figa <tomasz.figa@...il.com>
> Cc: Kukjin Kim <kgene.kim@...sung.com>
> Cc: Thomas Abraham <thomas.ab@...sung.com>
> Cc: Javier Martinez Canillas <javier@....samsung.com>
> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
> ---
>  arch/arm/mach-exynos/Kconfig  | 2 ++
>  arch/arm/mach-exynos/exynos.c | 2 ++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
> index 81064cd..491914c 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -25,6 +25,8 @@ menuconfig ARCH_EXYNOS
>  	select S5P_DEV_MFC
>  	select SRAM
>  	select MFD_SYSCON
> +	select THERMAL
> +	select EXYNOS_THERMAL
>  	help
>  	  Support for SAMSUNG EXYNOS SoCs (EXYNOS4/5)
>  
> diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
> index 77ac021..1c47aee 100644
> --- a/arch/arm/mach-exynos/exynos.c
> +++ b/arch/arm/mach-exynos/exynos.c
> @@ -227,6 +227,8 @@ static void __init exynos_init_irq(void)
>  static const struct of_device_id exynos_cpufreq_matches[] = {
>  	{ .compatible = "samsung,exynos3250", .data = "cpufreq-dt" },
>  	{ .compatible = "samsung,exynos4210", .data = "cpufreq-dt" },
> +	{ .compatible = "samsung,exynos4212", .data = "cpufreq-dt" },
> +	{ .compatible = "samsung,exynos4412", .data = "cpufreq-dt" },
>  	{ .compatible = "samsung,exynos5250", .data = "cpufreq-dt" },
>  	{ /* sentinel */ }
>  };
> 

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

Best regards,
Krzysztof

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