From patchwork Wed Dec 17 19:53:43 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sylvain Rochet X-Patchwork-Id: 5509091 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A7CF7BEEA8 for ; Wed, 17 Dec 2014 19:57:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D19E4209CF for ; Wed, 17 Dec 2014 19:57:07 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 98AD9209CD for ; Wed, 17 Dec 2014 19:57:06 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y1Kg2-0007t7-Kv; Wed, 17 Dec 2014 19:54:30 +0000 Received: from mx-guillaumet.finsecur.com ([91.217.234.131] helo=guillaumet.finsecur.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y1Kfx-0007n3-Ok for linux-arm-kernel@lists.infradead.org; Wed, 17 Dec 2014 19:54:26 +0000 Received: from [172.16.8.13] (helo=spice.lan) by guillaumet.finsecur.com with esmtps (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1Y1KfT-0001r0-IU; Wed, 17 Dec 2014 20:53:56 +0100 Received: from gradator by spice.lan with local (Exim 4.84) (envelope-from ) id 1Y1KfT-0002Fr-Bc; Wed, 17 Dec 2014 20:53:55 +0100 From: Sylvain Rochet To: linux-arm-kernel@lists.infradead.org, Nicolas Ferre , Ludovic Desroches Date: Wed, 17 Dec 2014 20:53:43 +0100 Message-Id: <1418846023-8581-1-git-send-email-sylvain.rochet@finsecur.com> X-Mailer: git-send-email 2.1.3 X-SA-Exim-Connect-IP: 172.16.8.13 X-SA-Exim-Mail-From: sylvain.rochet@finsecur.com X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Subject: [PATCH] ARM: at91/pit: don't suspend/resume if unused X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on guillaumet.finsecur.com) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141217_115425_962317_BE0A6EF7 X-CRM114-Status: UNSURE ( 9.14 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.0 (/) Cc: Sylvain Rochet X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Waiting for PIT to stop counting takes a long time: 1/(Master clock/prescaler/PIVR) = 1/(133 MHz /16 /2^20) = 126 ms Up to 126 ms if master clock is set to 133 MHz, skipping suspend/resume of the unused PIT device reduce (suspend time + resume time) from ~140 ms to ~17 ms. Signed-off-by: Sylvain Rochet Acked-by: Nicolas Ferre --- arch/arm/mach-at91/at91sam926x_time.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm/mach-at91/at91sam926x_time.c b/arch/arm/mach-at91/at91sam926x_time.c index e3344b4..44526aa 100644 --- a/arch/arm/mach-at91/at91sam926x_time.c +++ b/arch/arm/mach-at91/at91sam926x_time.c @@ -106,6 +106,10 @@ pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) static void at91sam926x_pit_suspend(struct clock_event_device *cedev) { + /* Don't suspend PIT if unused */ + if (cedev->mode == CLOCK_EVT_MODE_UNUSED) + return; + /* Disable timer */ pit_write(AT91_PIT_MR, 0); } @@ -125,6 +129,10 @@ static void at91sam926x_pit_reset(void) static void at91sam926x_pit_resume(struct clock_event_device *cedev) { + /* Don't resume PIT if unused */ + if (cedev->mode == CLOCK_EVT_MODE_UNUSED) + return; + at91sam926x_pit_reset(); }