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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 0FC0AC43219 for ; Tue, 30 Apr 2019 09:28:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA68321670 for ; Tue, 30 Apr 2019 09:28:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727106AbfD3J2w (ORCPT ); Tue, 30 Apr 2019 05:28:52 -0400 Received: from relay8-d.mail.gandi.net ([217.70.183.201]:45763 "EHLO relay8-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726945AbfD3J2d (ORCPT ); Tue, 30 Apr 2019 05:28:33 -0400 X-Originating-IP: 109.213.14.175 Received: from localhost (alyon-652-1-31-175.w109-213.abo.wanadoo.fr [109.213.14.175]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id 0943E1BF21C; Tue, 30 Apr 2019 09:28:30 +0000 (UTC) From: Alexandre Belloni To: linux-rtc@vger.kernel.org Cc: Paul Cercueil , Mathieu Malaterre , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Belloni Subject: [PATCH v2 6/7] rtc: jz4740: rework invalid time detection Date: Tue, 30 Apr 2019 11:28:20 +0200 Message-Id: <20190430092821.27963-6-alexandre.belloni@bootlin.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190430092821.27963-1-alexandre.belloni@bootlin.com> References: <20190430092821.27963-1-alexandre.belloni@bootlin.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The scratchpad register is used to detect an invalid time when power to the RTC has been lost. Instead of deleting that precious information and set the time to the UNIX epoch, forward it to userspace. Tested-by: Mathieu Malaterre Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-jz4740.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c index 32e6b6270efd..6dd00b654f93 100644 --- a/drivers/rtc/rtc-jz4740.c +++ b/drivers/rtc/rtc-jz4740.c @@ -157,6 +157,9 @@ static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time) uint32_t secs, secs2; int timeout = 5; + if (jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD) != 0x12345678) + return -EINVAL; + /* If the seconds register is read while it is updated, it can contain a * bogus value. This can be avoided by making sure that two consecutive * reads have the same value. @@ -180,8 +183,13 @@ static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time) static int jz4740_rtc_set_time(struct device *dev, struct rtc_time *time) { struct jz4740_rtc *rtc = dev_get_drvdata(dev); + int ret; + + ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time)); + if (ret) + return ret; - return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, rtc_tm_to_time64(time)); + return jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678); } static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) @@ -308,7 +316,6 @@ static int jz4740_rtc_probe(struct platform_device *pdev) { int ret; struct jz4740_rtc *rtc; - uint32_t scratchpad; struct resource *mem; const struct platform_device_id *id = platform_get_device_id(pdev); const struct of_device_id *of_id = of_match_device( @@ -376,16 +383,6 @@ static int jz4740_rtc_probe(struct platform_device *pdev) return ret; } - scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD); - if (scratchpad != 0x12345678) { - ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678); - ret = jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0); - if (ret) { - dev_err(&pdev->dev, "Could not write to RTC registers\n"); - return ret; - } - } - if (np && of_device_is_system_power_controller(np)) { if (!pm_power_off) { /* Default: 60ms */ -- 2.20.1