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=-5.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 0CB4FC31E5C for ; Mon, 17 Jun 2019 21:30:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D33DB2063F for ; Mon, 17 Jun 2019 21:30:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560807036; bh=i9Ko+0/eQ4ec+hUVmpS3MjI3uwmIUDUjQmFTmcYNk1s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=b6GHpuoMghevboqJ44Z8wwjtZcYtyY40fQPQND/vBW8RdY+HAT2zUecKg1tqEaGAO T+Mx/or4uUC0bAK/zYofuwSt5fXNBWViT4rvli0sSnuFGNLx+IkRGWV6fVCqLr4oiz XkB9dEREqqSqm15tLGPQvAhMA+BP3v49A79cavpc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730767AbfFQV36 (ORCPT ); Mon, 17 Jun 2019 17:29:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:57172 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730763AbfFQV36 (ORCPT ); Mon, 17 Jun 2019 17:29:58 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9CB882063F; Mon, 17 Jun 2019 21:29:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806998; bh=i9Ko+0/eQ4ec+hUVmpS3MjI3uwmIUDUjQmFTmcYNk1s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4FuHOyq/LcCOPsvzeVcD9GCx9c1k+kb4wtRuoQqkjEP8RhKolEm66DRGM8QAvJpJ GZeRD02GCp/TSNSmPtE2xvJRXFuH0OUVlVZMfnz23givu6ztumKnfRIbXHV7av9Hpr JMO6ogiiAHDXbNLak6jnS8jypOGrWbcimLPErfTs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Erik=20=C4=8Cuk?= , Baruch Siach , Alexandre Belloni Subject: [PATCH 4.14 53/53] rtc: pcf8523: dont return invalid date when battery is low Date: Mon, 17 Jun 2019 23:10:36 +0200 Message-Id: <20190617210752.684594543@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190617210745.104187490@linuxfoundation.org> References: <20190617210745.104187490@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Baruch Siach commit ecb4a353d3afd45b9bb30c85d03ee113a0589079 upstream. The RTC_VL_READ ioctl reports the low battery condition. Still, pcf8523_rtc_read_time() happily returns invalid dates in this case. Check the battery health on pcf8523_rtc_read_time() to avoid that. Reported-by: Erik Čuk Signed-off-by: Baruch Siach Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-pcf8523.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -82,6 +82,18 @@ static int pcf8523_write(struct i2c_clie return 0; } +static int pcf8523_voltage_low(struct i2c_client *client) +{ + u8 value; + int err; + + err = pcf8523_read(client, REG_CONTROL3, &value); + if (err < 0) + return err; + + return !!(value & REG_CONTROL3_BLF); +} + static int pcf8523_select_capacitance(struct i2c_client *client, bool high) { u8 value; @@ -164,6 +176,14 @@ static int pcf8523_rtc_read_time(struct struct i2c_msg msgs[2]; int err; + err = pcf8523_voltage_low(client); + if (err < 0) { + return err; + } else if (err > 0) { + dev_err(dev, "low voltage detected, time is unreliable\n"); + return -EINVAL; + } + msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = 1; @@ -248,17 +268,13 @@ static int pcf8523_rtc_ioctl(struct devi unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); - u8 value; - int ret = 0, err; + int ret; switch (cmd) { case RTC_VL_READ: - err = pcf8523_read(client, REG_CONTROL3, &value); - if (err < 0) - return err; - - if (value & REG_CONTROL3_BLF) - ret = 1; + ret = pcf8523_voltage_low(client); + if (ret < 0) + return ret; if (copy_to_user((void __user *)arg, &ret, sizeof(int))) return -EFAULT;