From: tomasz.figa@gmail.com (Tomasz Figa)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v9 6/6] clk: samsung: remove unused clock aliases and update clock flags
Date: Thu, 31 Jul 2014 20:35:28 +0200 [thread overview]
Message-ID: <53DA8C70.2060009@gmail.com> (raw)
In-Reply-To: <CAJuA9ahCVnG8st0t_U+Nw9+eHV3fh57EjUeJw=LxCA0QzSm=AA@mail.gmail.com>
On 31.07.2014 20:24, Thomas Abraham wrote:
> Hi Tomasz,
>
> On Thu, Jul 31, 2014 at 7:43 PM, Tomasz Figa <tomasz.figa@gmail.com> wrote:
>> On 30.07.2014 10:07, Thomas Abraham wrote:
>>> With some of the Exynos SoCs switched over to use the generic CPUfreq drivers,
>>> the unused clock aliases can be removed. In addition to this, the individual
>>> clock blocks which are now encapsulated with the consolidate CPU clock type
>>> can now be marked with read-only flags.
>>
>> [snip]
>>
>>> @@ -1500,6 +1499,7 @@ static void __init exynos4_clk_init(struct device_node *np,
>>> exynos4_soc == EXYNOS4210 ? "Exynos4210" : "Exynos4x12",
>>> _get_rate("sclk_apll"), _get_rate("sclk_mpll"),
>>> _get_rate("sclk_epll"), _get_rate("sclk_vpll"),
>>> + exynos4_soc == EXYNOS4210 ? _get_rate("armclk") :
>>> _get_rate("div_core2"));
>>
>> I believe "div_core2" should work fine here for all SoCs without the
>> need for this if.
>
> The following patch is a pre-requisite for this patch.
> http://www.spinics.net/lists/arm-kernel/msg351540.html
>
> The rate can be obtained from div_core2 as well but with the cpu clock
> now registered, the rate can be obtained from the cpu clock instance
> instead of the div_core2 divider. And when Exynos4412 also add cpu
> clock instance, the 'if' above will be removed.
>
>>
>>> }
>>>
>>> diff --git a/drivers/clk/samsung/clk-exynos5250.c b/drivers/clk/samsung/clk-exynos5250.c
>>> index e19e365..1d958f1 100644
>>> --- a/drivers/clk/samsung/clk-exynos5250.c
>>> +++ b/drivers/clk/samsung/clk-exynos5250.c
>>
>> [snip]
>>
>>> @@ -848,6 +851,6 @@ static void __init exynos5250_clk_init(struct device_node *np)
>>> samsung_clk_of_add_provider(np, ctx);
>>>
>>> pr_info("Exynos5250: clock setup completed, armclk=%ld\n",
>>> - _get_rate("div_arm2"));
>>> + _get_rate("armclk"));
>>
>> Similarly here, no need for this change.
>
> Same here. Instead of getting the rate from div_core2 divider block,
> the cpu clock instance is used to find the rate. I would prefer to use
> cpu clock here. Is there any reason to prefer div_core2 over the cpu
> clock instance?
Well, the reason is simple: if you don't need to change something (i.e.
the change doesn't have any advantages), don't change it.
There is no difference between obtaining the rate from div_{arm,core}2
and armclk, so I don't see the point of changing this.
In fact now when thinking of it, this has revealed one hole that will be
unhandled by your code - if cpufreq is disabled and the bootloader
configures div_{arm,core}{,2} with non-zero values, armclk will return
incorrect rate. However since I haven't observed such case on existing
platforms, fixing this might be done on top of this series, in a
separate patch.
Best regards,
Tomasz
next prev parent reply other threads:[~2014-07-31 18:35 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 8:07 [PATCH v9 0/6] cpufreq: use generic cpufreq drivers for exynos platforms Thomas Abraham
2014-07-30 8:07 ` [PATCH v9 1/6] clk: samsung: add infrastructure to register cpu clocks Thomas Abraham
2014-09-01 22:29 ` Mike Turquette
2014-09-02 13:53 ` Thomas Abraham
2014-07-30 8:07 ` [PATCH v9 2/6] clk: samsung: add cpu clock configuration data and instantiate cpu clock Thomas Abraham
2014-09-01 22:29 ` Mike Turquette
2014-07-30 8:07 ` [PATCH v9 3/6] ARM: dts: Exynos: add CPU OPP and regulator supply property Thomas Abraham
2014-07-30 11:28 ` Andreas Färber
2014-07-31 2:55 ` Thomas Abraham
2014-07-31 0:37 ` Doug Anderson
2014-07-31 3:21 ` Thomas Abraham
2014-07-31 3:53 ` Doug Anderson
2014-07-31 4:06 ` Thomas Abraham
2014-07-31 4:08 ` Doug Anderson
2014-07-31 4:18 ` Thomas Abraham
2014-08-02 3:49 ` Javier Martinez Canillas
2014-08-04 3:00 ` Thomas Abraham
2014-07-30 8:07 ` [PATCH v9 4/6] ARM: Exynos: switch to using generic cpufreq driver for Exynos4210/5250/5420 Thomas Abraham
2014-07-31 18:32 ` Kukjin Kim
2014-07-31 18:40 ` Tomasz Figa
2014-07-31 18:54 ` Tomasz Figa
2014-07-31 19:25 ` Thomas Abraham
2014-07-31 19:30 ` Tomasz Figa
2014-08-04 3:24 ` Thomas Abraham
2014-08-22 23:54 ` Kevin Hilman
2014-08-23 0:02 ` Tomasz Figa
2014-08-25 6:53 ` Lukasz Majewski
2014-08-25 12:15 ` Chander Kashyap
2014-08-25 15:32 ` Kevin Hilman
2014-08-25 15:56 ` Tomasz Figa
2014-08-26 4:54 ` Viresh Kumar
2014-08-26 5:25 ` Chander Kashyap
2014-08-26 15:15 ` Kevin Hilman
2014-08-26 22:25 ` Kevin Hilman
2014-08-29 12:52 ` Thomas Abraham
2014-08-29 15:03 ` Kevin Hilman
2014-09-01 8:47 ` Thomas Abraham
2014-09-02 19:32 ` Kevin Hilman
2014-09-03 4:26 ` Thomas Abraham
2014-09-03 13:18 ` Thomas Abraham
2014-09-03 23:15 ` Kevin Hilman
2014-09-04 10:22 ` Thomas Abraham
2014-09-04 13:30 ` Kevin Hilman
2014-09-05 13:41 ` Thomas Abraham
2014-08-25 8:11 ` Sjoerd Simons
2014-07-30 8:07 ` [PATCH v9 5/6] cpufreq: exynos: remove exynos4210/5250 specific cpufreq driver support Thomas Abraham
2014-07-30 8:07 ` [PATCH v9 6/6] clk: samsung: remove unused clock aliases and update clock flags Thomas Abraham
2014-07-31 14:13 ` Tomasz Figa
2014-07-31 18:24 ` Thomas Abraham
2014-07-31 18:35 ` Tomasz Figa [this message]
2014-07-31 18:41 ` Thomas Abraham
2014-07-31 18:46 ` Tomasz Figa
2014-07-31 18:49 ` Thomas Abraham
2014-09-01 22:31 ` Mike Turquette
2014-07-31 6:20 ` [PATCH v9 0/6] cpufreq: use generic cpufreq drivers for exynos platforms Chander M. Kashyap
2014-07-31 10:59 ` Thomas Abraham
2014-07-31 12:24 ` Chander M. Kashyap
2014-07-31 14:15 ` Tomasz Figa
2014-07-31 18:25 ` Thomas Abraham
2014-07-31 18:34 ` Thomas Abraham
2014-08-01 9:42 ` Viresh Kumar
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