From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6C98C3A5A1 for ; Thu, 22 Aug 2019 07:44:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 826AD206BB for ; Thu, 22 Aug 2019 07:44:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728332AbfHVHoS (ORCPT ); Thu, 22 Aug 2019 03:44:18 -0400 Received: from mga12.intel.com ([192.55.52.136]:55136 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727875AbfHVHoS (ORCPT ); Thu, 22 Aug 2019 03:44:18 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Aug 2019 00:44:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,415,1559545200"; d="scan'208";a="378414146" Received: from sgsxdev001.isng.intel.com (HELO localhost) ([10.226.88.11]) by fmsmga005.fm.intel.com with ESMTP; 22 Aug 2019 00:44:13 -0700 From: Rahul Tanwar To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, tony.luck@intel.com, x86@kernel.org, a.zummo@towertech.it, alexandre.belloni@bootlin.com, robh+dt@kernel.org, mark.rutland@arm.com Cc: linux-rtc@vger.kernel.org, devicetree@vger.kernel.org, andriy.shevchenko@intel.com, alan@linux.intel.com, linux-kernel@vger.kernel.org, qi-ming.wu@intel.com, cheol.yong.kim@intel.com, rahul.tanwar@intel.com, Rahul Tanwar Subject: [PATCH v1 1/2] x86/rtc: Add option to skip using RTC Date: Thu, 22 Aug 2019 15:44:03 +0800 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org Use a newly introduced optional "status" property of "motorola,mc146818" compatible DT node to determine if RTC is supported. Skip read/write from RTC device only when this node is present and status is "disabled". In all other cases, proceed as before. Suggested-by: Alan Cox Signed-off-by: Rahul Tanwar --- arch/x86/kernel/rtc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index 586f718b8e95..f9f760a8e76a 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -32,6 +32,11 @@ EXPORT_SYMBOL(cmos_lock); DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL(rtc_lock); +static const struct of_device_id of_cmos_match[] = { + { .compatible = "motorola,mc146818" }, + {} +}; + /* * In order to set the CMOS clock precisely, set_rtc_mmss has to be * called 500 ms after the second nowtime has started, because when @@ -42,9 +47,14 @@ EXPORT_SYMBOL(rtc_lock); int mach_set_rtc_mmss(const struct timespec64 *now) { unsigned long long nowtime = now->tv_sec; + struct device_node *node; struct rtc_time tm; int retval = 0; + node = of_find_matching_node(NULL, of_cmos_match); + if (node && !of_device_is_available(node)) + return -EINVAL; + rtc_time64_to_tm(nowtime, &tm); if (!rtc_valid_tm(&tm)) { retval = mc146818_set_time(&tm); @@ -63,8 +73,15 @@ int mach_set_rtc_mmss(const struct timespec64 *now) void mach_get_cmos_time(struct timespec64 *now) { unsigned int status, year, mon, day, hour, min, sec, century = 0; + struct device_node *node; unsigned long flags; + node = of_find_matching_node(NULL, of_cmos_match); + if (node && !of_device_is_available(node)) { + now->tv_sec = now->tv_nsec = 0; + return; + } + /* * If pm_trace abused the RTC as storage, set the timespec to 0, * which tells the caller that this RTC value is unusable. -- 2.11.0