From patchwork Thu Jan 31 15:32:00 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Santosh Shilimkar X-Patchwork-Id: 2074151 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 87DB13FCDE for ; Thu, 31 Jan 2013 15:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754876Ab3AaPbJ (ORCPT ); Thu, 31 Jan 2013 10:31:09 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:54937 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754862Ab3AaPbI (ORCPT ); Thu, 31 Jan 2013 10:31:08 -0500 Received: from dbdp20.itg.ti.com ([172.24.170.38]) by arroyo.ext.ti.com (8.13.7/8.13.7) with ESMTP id r0VFUtZf023836; Thu, 31 Jan 2013 09:30:56 -0600 Received: from DBDE71.ent.ti.com (localhost [127.0.0.1]) by dbdp20.itg.ti.com (8.13.8/8.13.8) with ESMTP id r0VFUoMi029642; Thu, 31 Jan 2013 21:00:51 +0530 (IST) Received: from dbdp32.itg.ti.com (172.24.170.251) by DBDE71.ent.ti.com (172.24.170.149) with Microsoft SMTP Server id 14.1.323.3; Thu, 31 Jan 2013 21:00:50 +0530 Received: from ula0393909.apr.dhcp.ti.com (smtpvbd.itg.ti.com [172.24.170.250]) by dbdp32.itg.ti.com (8.13.8/8.13.8) with ESMTP id r0VFUjJ8032098; Thu, 31 Jan 2013 21:00:46 +0530 From: Santosh Shilimkar To: CC: , Santosh Shilimkar , Arnd Bergmann , Russell King , John Stultz , Tony Lindgren Subject: [PATCH] ARM: OMAP2+: Get rid of custom OMAP_32K_TIMER_HZ Date: Thu, 31 Jan 2013 21:02:00 +0530 Message-ID: <1359646320-9086-1-git-send-email-santosh.shilimkar@ti.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org The timekeeping doesn't depend on HZ value in presence of fine grained clocksource and hence there should not be any time drift because of HZ value which was chosen to be divisor of 32768. OMAP has been using HZ = 128 value to avoid any time drift issues because of 32768 HZ clock. But with various measurements performed with HZ = 100, no time drift is observed and it also proves the point about HZ not having impact on time keeping on OMAP. Very informative thread on this topic is here: https://lkml.org/lkml/2013/1/29/435 Special thanks to John Stulz, Arnd Bergmann and Russell King for their valuable suggestions. Cc: Arnd Bergmann Cc: Russell King Cc: John Stultz Cc: Tony Lindgren Signed-off-by: Santosh Shilimkar Tested-by: Lokesh Vutla Acked-by: Arnd Bergmann Acked-by: Igor Grinberg --- arch/arm/Kconfig | 1 - arch/arm/plat-omap/Kconfig | 9 --------- arch/arm/plat-omap/include/plat/timex.h | 8 -------- 3 files changed, 18 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index b35b27f..5493164 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1648,7 +1648,6 @@ config HZ int default 200 if ARCH_EBSA110 || ARCH_S3C24XX || ARCH_S5P64X0 || \ ARCH_S5PV210 || ARCH_EXYNOS4 - default OMAP_32K_TIMER_HZ if ARCH_OMAP && OMAP_32K_TIMER default AT91_TIMER_HZ if ARCH_AT91 default SHMOBILE_TIMER_HZ if ARCH_SHMOBILE default 100 diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig index 67c859c..ce66eb9 100644 --- a/arch/arm/plat-omap/Kconfig +++ b/arch/arm/plat-omap/Kconfig @@ -147,15 +147,6 @@ config OMAP3_L2_AUX_SECURE_SERVICE_SET_ID help PPA routine service ID for setting L2 auxiliary control register. -config OMAP_32K_TIMER_HZ - int "Kernel internal timer frequency for 32KHz timer" - range 32 1024 - depends on OMAP_32K_TIMER - default "128" - help - Kernel internal timer frequency should be a divisor of 32768, - such as 64 or 128. - config OMAP_DM_TIMER bool "Use dual-mode timer" depends on ARCH_OMAP16XX || ARCH_OMAP2PLUS diff --git a/arch/arm/plat-omap/include/plat/timex.h b/arch/arm/plat-omap/include/plat/timex.h index 6d35767..e27d2da 100644 --- a/arch/arm/plat-omap/include/plat/timex.h +++ b/arch/arm/plat-omap/include/plat/timex.h @@ -28,14 +28,6 @@ #if !defined(__ASM_ARCH_OMAP_TIMEX_H) #define __ASM_ARCH_OMAP_TIMEX_H -/* - * OMAP 32KHz timer updates time one jiffie at a time from a secondary timer, - * and that's why the CLOCK_TICK_RATE is not 32768. - */ -#ifdef CONFIG_OMAP_32K_TIMER -#define CLOCK_TICK_RATE (CONFIG_OMAP_32K_TIMER_HZ) -#else #define CLOCK_TICK_RATE (HZ * 100000UL) -#endif #endif /* __ASM_ARCH_OMAP_TIMEX_H */