Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933072Ab3JOPih (ORCPT ); Tue, 15 Oct 2013 11:38:37 -0400 Received: from mail-vb0-f54.google.com ([209.85.212.54]:39179 "EHLO mail-vb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932828Ab3JOPid (ORCPT ); Tue, 15 Oct 2013 11:38:33 -0400 MIME-Version: 1.0 In-Reply-To: References: <1381490814-20890-1-git-send-email-ch.naveen@samsung.com> <1381818232-12542-1-git-send-email-ch.naveen@samsung.com> Date: Tue, 15 Oct 2013 08:38:32 -0700 X-Google-Sender-Auth: z8IxqpNCI-E_nJ0H0HaV9t9DwVU Message-ID: Subject: Re: [PATCH v2] i2c: s3c2410: dont need CPU_FREQ transitions for exynos series From: Doug Anderson To: Kyungmin Park Cc: Naveen Krishna Chatradhi , "linux-i2c@vger.kernel.org" , Tomasz Figa , Simon Glass , "linux-kernel@vger.kernel.org" , linux-samsung-soc , Wolfram Sang , Ben Dooks , Grant Likely , "broonie@kernel.org" , "cpgs ." Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1833 Lines: 44 Hi, On Mon, Oct 14, 2013 at 11:56 PM, Kyungmin Park wrote: > On Tue, Oct 15, 2013 at 3:23 PM, Naveen Krishna Chatradhi > wrote: >> For Exynos4 and Exynos5 SoCs from Samsung the 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 if CONFIG_CPU_FREQ_S3C24XX is enabled. >> >> This change should save a bunch of cpufreq transitions calls >> which does not apply to exynos SoCs. >> >> Signed-off-by: Naveen Krishna Chatradhi > Acked-by: Kyungmin Park >> --- >> Changes since v1: >> Use CONFIG_CPU_FREQ_S3C24XX instead of (CONFIG_CPU_FREQ & !CONFIG_EXYNOS) >> As commented by Tomasz >> >> drivers/i2c/busses/i2c-s3c2410.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) Looks great to me. Thank you for the suggestions Tomasz, as always. Reviewed-by: Doug Anderson We need to come up with a solution for the CPU_FREQ stuff in s3c2410_wdt too. We could use a similar solution but since the CPU_FREQ stuff in s3c2410_wdt is more than just an optimization it means that it's not good if S3C24XX is included in a multiplatform kernel. (For the watchdog it's more than just an optimization since every frequency transition actually pets the watchdog, making it useless when you transition several times per second). -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/