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=ham 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 BC5E8C282C2 for ; Fri, 25 Jan 2019 14:36:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E324218D0 for ; Fri, 25 Jan 2019 14:36:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726216AbfAYOgG (ORCPT ); Fri, 25 Jan 2019 09:36:06 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:54949 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726238AbfAYOgF (ORCPT ); Fri, 25 Jan 2019 09:36:05 -0500 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gn2aR-0001ke-IM; Fri, 25 Jan 2019 15:36:03 +0100 Received: from ukl by dude.hi.pengutronix.de with local (Exim 4.92-RC4) (envelope-from ) id 1gn2aQ-0007BE-4M; Fri, 25 Jan 2019 15:36:02 +0100 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= To: Alexandre Belloni Cc: Marek Vasut , kernel@pengutronix.de, linux-rtc@vger.kernel.org Subject: [PATCH 4/5] rtc: ds1307: rx8130: honor Voltage Loss Flag when reading the time Date: Fri, 25 Jan 2019 15:35:57 +0100 Message-Id: <20190125143558.27450-4-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190125143558.27450-1-u.kleine-koenig@pengutronix.de> References: <20190125143558.27450-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-rtc@vger.kernel.org Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.org When voltage dropped since the RTC was last set the reported time is not reliable. In this case return an error indicator instead of a bogus time. Signed-off-by: Uwe Kleine-König --- drivers/rtc/rtc-ds1307.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index 81e20653700d..974eafda9de4 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -194,6 +194,20 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t) const struct chip_desc *chip = &chips[ds1307->type]; u8 regs[7]; + if (ds1307->type == rx_8130) { + unsigned int regflag; + ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, ®flag); + if (ret) { + dev_err(dev, "%s error %d\n", "read", ret); + return ret; + } + + if (regflag & RX8130_REG_FLAG_VLF) { + dev_warn_once(dev, "oscillator failed, set time!\n"); + return -EINVAL; + } + } + /* read the RTC date and time registers all at once */ ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs, sizeof(regs)); @@ -293,6 +307,17 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t) dev_err(dev, "%s error %d\n", "write", result); return result; } + + if (ds1307->type == rx_8130) { + /* clear Voltage Loss Flag as data is available now */ + result = regmap_write(ds1307->regmap, RX8130_REG_FLAG, + ~(u8)RX8130_REG_FLAG_VLF); + if (result) { + dev_err(dev, "%s error %d\n", "write", result); + return result; + } + } + return 0; } -- 2.20.1