From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Re: [PATCH] watchdog: s3c2410_wdt: Only register for cpufreq on CPU_FREQ_S3C24XX Date: Tue, 26 Nov 2013 00:08:31 +0000 Message-ID: <20131126000831.GW12108@trinity.fluff.org> References: <1385420137-32725-1-git-send-email-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1385420137-32725-1-git-send-email-dianders@chromium.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Doug Anderson Cc: Kukjin Kim , linux-watchdog@vger.kernel.org, Leela Krishna Amudala , Tomasz Figa , linux-kernel@vger.kernel.org, Wim Van Sebroeck , linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Ben Dooks , Olof Johansson , Guenter Roeck List-Id: linux-samsung-soc@vger.kernel.org On Mon, Nov 25, 2013 at 02:55:37PM -0800, Doug Anderson wrote: > On modern SoCs the watchdog timer is parented on a clock that doesn't > change every time we have a cpufreq change. That means we don't need > to constantly adjust the watchdog timer, so avoid registering for and > dealing with cpufreq transitions unless we've actually got > CPU_FREQ_S3C24XX defined. The S3C2410 to at-least S3C2440 there is only one PLL/clock-divider set so changing any part of that can change frequency supplied to the watchdog. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 26 Nov 2013 00:08:31 +0000 From: Ben Dooks To: Doug Anderson Cc: Wim Van Sebroeck , Guenter Roeck , Leela Krishna Amudala , Olof Johansson , Tomasz Figa , Kukjin Kim , Ben Dooks , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] watchdog: s3c2410_wdt: Only register for cpufreq on CPU_FREQ_S3C24XX Message-ID: <20131126000831.GW12108@trinity.fluff.org> References: <1385420137-32725-1-git-send-email-dianders@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1385420137-32725-1-git-send-email-dianders@chromium.org> List-ID: On Mon, Nov 25, 2013 at 02:55:37PM -0800, Doug Anderson wrote: > On modern SoCs the watchdog timer is parented on a clock that doesn't > change every time we have a cpufreq change. That means we don't need > to constantly adjust the watchdog timer, so avoid registering for and > dealing with cpufreq transitions unless we've actually got > CPU_FREQ_S3C24XX defined. The S3C2410 to at-least S3C2440 there is only one PLL/clock-divider set so changing any part of that can change frequency supplied to the watchdog. From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben@trinity.fluff.org (Ben Dooks) Date: Tue, 26 Nov 2013 00:08:31 +0000 Subject: [PATCH] watchdog: s3c2410_wdt: Only register for cpufreq on CPU_FREQ_S3C24XX In-Reply-To: <1385420137-32725-1-git-send-email-dianders@chromium.org> References: <1385420137-32725-1-git-send-email-dianders@chromium.org> Message-ID: <20131126000831.GW12108@trinity.fluff.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Nov 25, 2013 at 02:55:37PM -0800, Doug Anderson wrote: > On modern SoCs the watchdog timer is parented on a clock that doesn't > change every time we have a cpufreq change. That means we don't need > to constantly adjust the watchdog timer, so avoid registering for and > dealing with cpufreq transitions unless we've actually got > CPU_FREQ_S3C24XX defined. The S3C2410 to at-least S3C2440 there is only one PLL/clock-divider set so changing any part of that can change frequency supplied to the watchdog.