From mboxrd@z Thu Jan 1 00:00:00 1970 From: Naveen Krishna Ch Subject: Re: [PATCH] i2c: s3c2410: dont need CPU_FREQ transitions for exynos series Date: Sat, 12 Oct 2013 12:06:34 +0530 Message-ID: References: <1381490814-20890-1-git-send-email-ch.naveen@samsung.com> <3245175.os31ym2KFi@amdn883> <2030813.WOPcW68yit@amdn883> <5982877.kDV2Xg8Ocr@amdn883> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: In-Reply-To: <5982877.kDV2Xg8Ocr@amdn883> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tomasz Figa Cc: Naveen Krishna Chatradhi , sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org, khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org, Ben Dooks , grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org, broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, cpgs-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 12 October 2013 11:12, Tomasz Figa wrote: > On Saturday 12 of October 2013 04:28:51 Tomasz Figa wrote: >> [Fixing incorrent mail addresses and dropping the old DT ML.] >> >> On Saturday 12 of October 2013 04:22:04 Tomasz Figa wrote: >> > Hi Naveen, >> > >> > On Friday 11 of October 2013 16:56:54 Naveen Krishna Chatradhi wrote: >> > > The exynos5 i2c clock is based on a fixed 66 MHz peripheral clock, and >> > > therefore is completely independent of the cpu frequency. >> > > Thus, registering for a CPU freq notifier is very wasteful. >> > > >> > > This patch modifes the code such that, i2c bus registers to >> > > cpu_freq_transition only for non Exynos SoCs. >> > > >> > > This change should save a bunch of cpufreq transitions calls >> > > which does not apply to exynos SoCs. >> > >> > The idea is fine, although... >> > >> > > Signed-off-by: Naveen Krishna Chatradhi >> > > --- >> > > drivers/i2c/busses/i2c-s3c2410.c | 4 ++-- >> > > 1 file changed, 2 insertions(+), 2 deletions(-) >> > > >> > > diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c >> > > index cab1c91..d062fa7 100644 >> > > --- a/drivers/i2c/busses/i2c-s3c2410.c >> > > +++ b/drivers/i2c/busses/i2c-s3c2410.c >> > > @@ -123,7 +123,7 @@ struct s3c24xx_i2c { >> > > struct s3c2410_platform_i2c *pdata; >> > > int gpios[2]; >> > > struct pinctrl *pctrl; >> > > -#ifdef CONFIG_CPU_FREQ >> > > +#if defined(CONFIG_CPU_FREQ) && !defined(CONFIG_ARCH_EXYNOS) >> > >> > ...this is not a good coding practice, especially when already having >> > multiplatform kernels in sight. >> > >> > The best way would be to check on which SoC we are running at runtime, >> > but since this might need changing a lot of code, then at least I would >> > change this from !defined(EXYNOS) to defined(S3C24XX), so it is not being >> > compiled in when S3C24XX support is not enabled and if it's enabled then >> > the notifier will be registered as a safe fallback that will run correctly >> > on all platforms. > > Actually you can simply check for CONFIG_CPU_FREQ_S3C24XX here. sure, this makes it more meaningful. will make the modifications and resubmit. > > Best regards, > Tomasz > -- Shine bright, (: Nav :)