From patchwork Mon Jun 12 11:30:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rasmus Villemoes X-Patchwork-Id: 106529 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp2522145vqr; Mon, 12 Jun 2023 04:41:31 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4nKfdfx6qVL6wmkVf8/2DYgWoG61nB07UU/RBCTCoVnW7iMxS3V0joBPL4+dslpn6ooLRQ X-Received: by 2002:a05:6a00:1509:b0:65f:2fbd:370a with SMTP id q9-20020a056a00150900b0065f2fbd370amr10119056pfu.30.1686570091020; Mon, 12 Jun 2023 04:41:31 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686570091; cv=none; d=google.com; s=arc-20160816; b=SFnEna494oyUIvI+wJFgHCOk+LpU6TlBs4zONDbKOo0OE6Zgx72mba99sOPJhscDKU 0rZqVo/viJ0xIA0gnFEmqds0m7FPfNlxt+RUb28q37Ns+D2Q7bXqGgUQo4WP7nad/jPD 2HFXr577vraxdc5PDlVilPgtreziqCYgjCHThFxwdbqp+0BBuC70CmtUjaNXrxTLS00z KUyH/hsqkmPr1ngpWI86UcObuZZ4Y9FlIf5OB/47DMqffmY6WDy8tyoTcXggTgOjuesz eBmD8T7pn8so6+HyS5MwmUUxK0Y52iXbQ2yZUfuirgVNJM1JnVrtAySYC3nrClxyAeBO 3rRQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=jgVb0YJLMNEKVO6C16PIZb2dGiXFxsfavrt5+857HKY=; b=emRUOEDGGvHPF6FHS0nEafQd+eVT55mDWBNF4ZuHqR4tQNA+sgJmqgQccBrVHOknxX NwSg3sUgUb7AkJpVmgimag6/1g1I99Rdm9FcF8a8mO7IGb3grL+j35FaTNHDRBScOVTK M8ibAOeTo4U1DS6YAfU18LNLe23e7pXdRYxSCMaEKoTWd/zP0/kTxAQEU4pLlJOHeg5m qSqTerOi6SNjsgh0tJpZ8MVYzhey+h2dJKZPwBqehp5C2hlT4yWefH0AK18A9pFT/CMZ oWpHnBSxxpKj+TD86wtmXD0dOagDCIGrViMTlNBzpXz2PGebgWajiK+ezUbayB51iOuv 1zQA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@rasmusvillemoes.dk header.s=google header.b=i4Mh2nE9; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id z7-20020aa79907000000b00640f330a547si3186545pff.236.2023.06.12.04.41.18; Mon, 12 Jun 2023 04:41:31 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@rasmusvillemoes.dk header.s=google header.b=i4Mh2nE9; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233231AbjFLLjd (ORCPT + 99 others); Mon, 12 Jun 2023 07:39:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233676AbjFLLiY (ORCPT ); Mon, 12 Jun 2023 07:38:24 -0400 Received: from mail-lf1-x12b.google.com (mail-lf1-x12b.google.com [IPv6:2a00:1450:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BC2FF46BB for ; Mon, 12 Jun 2023 04:31:05 -0700 (PDT) Received: by mail-lf1-x12b.google.com with SMTP id 2adb3069b0e04-4f658a17aa4so3961597e87.0 for ; Mon, 12 Jun 2023 04:31:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; t=1686569464; x=1689161464; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=jgVb0YJLMNEKVO6C16PIZb2dGiXFxsfavrt5+857HKY=; b=i4Mh2nE9YuLTcp2XbpN/eOJwtngu0h1LWO9aEmixp8l0pyW240BMU1J8Q5ABCGlWUM jI57wN1NNeplslst7Ooc8X23+g2BbnCZoA+tMrbPziCy7MgKwyoPhIguKO8jGDCei/5e sbEiItj88sX5FlOPjAzWrmWQbWCrHEad1yJ2Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686569464; x=1689161464; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=jgVb0YJLMNEKVO6C16PIZb2dGiXFxsfavrt5+857HKY=; b=iSqb1amk9bquV6dMbsNCJlJbgK2qTuQGheOH+sg4yyq7av1q68atAULLZV3gEhWF1o MsRocG042WcR27r5zEiUYz8D9YKwyQ+df8S8MXkHVb1cWmEHR5WzIkGpNMOWw+uPbvb1 z+sdyUQIsMyOgMQEQIg1GIJ7HzlHKvLl+fZaiaIjCaPF7QMjBg3a3X5M6P3mFU3GLmFe 0gC+C012VZGseAuLbbrNLjQCRBxEqbQ+AwS3kFmR0zr0ZeHSLuSBL0x4BYjSAfSdf9F5 Ogd1pTZkCAdxbvaXNbygvgIHFKkTSsMJ45p9tnVBI5LWAGFeYJDQqevT274iLBXfX+FX 6gTQ== X-Gm-Message-State: AC+VfDzbl+V8e2o/SkgONloMVBhrqP1oQpUs0oXPFujxEzbv3f+a0rhV DCTACNl7vs11loVH9688y2wdlQ== X-Received: by 2002:a19:7712:0:b0:4e8:c5d:42a5 with SMTP id s18-20020a197712000000b004e80c5d42a5mr3117418lfc.24.1686569463965; Mon, 12 Jun 2023 04:31:03 -0700 (PDT) Received: from prevas-ravi.prevas.se ([81.216.59.226]) by smtp.gmail.com with ESMTPSA id w26-20020a19c51a000000b004edb8fac1cesm1399320lfe.215.2023.06.12.04.31.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jun 2023 04:31:03 -0700 (PDT) From: Rasmus Villemoes To: Alessandro Zummo , Alexandre Belloni Cc: Andy Shevchenko , devicetree@vger.kernel.org, Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-rtc@vger.kernel.org, Rasmus Villemoes , linux-kernel@vger.kernel.org Subject: [PATCH 1/8] rtc: isl12022: remove wrong warning for low battery level Date: Mon, 12 Jun 2023 13:30:51 +0200 Message-Id: <20230612113059.247275-2-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20230612113059.247275-1-linux@rasmusvillemoes.dk> References: <20230612113059.247275-1-linux@rasmusvillemoes.dk> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768496919683347456?= X-GMAIL-MSGID: =?utf-8?q?1768496919683347456?= There are multiple problems with this warning. First of all, it triggers way too often, in fact nearly on every boot, because the SR_LBAT85/SR_LBAT75 bits have another meaning when in battery backup mode. Quoting from the data sheet: LOW BATTERY INDICATOR 85% BIT (LBAT85) In Normal Mode (VDD), this bit indicates when the battery level has dropped below the pre-selected trip levels. [...] The LBAT85 detection happens automatically once every minute when seconds register reaches 59. In Battery Mode (VBAT), this bit indicates the device has entered into battery mode by polling once every 10 minutes. The LBAT85 detection happens automatically once when the minute register reaches x9h or x0h minutes. Similar wording applies to the LBAT75 bit. This means that if the device is powered off for more than 10 minutes, the LBAT85 bit is guaranteed to be set. Upon power-on, unless we're close enough to the end of a minute and/or the boot is slow enough that the second register passes 59, the LBAT85 bit is still set when the kernel (or early userspace) reads the RTC to set the system's wallclock time. Another minor problem is with the bit logic. If the 75% level is reached, logically we're also below 85%, so both bits would most likely be set. So even if the battery is below 75%, the warning would still say "voltage dropped below 85%". A third problem is that the driver and current DT binding offer no way to indicate the nominal battery level and/or settings of the Battery Level Monitor Trip Bits. Since the default value of the VB85TP[2:0] and VB75TP[2:0] bits are 000, this means the actual setting of the LBAT85/LBAT75 bits in VDD mode doesn't happen until the battery is below 2.125V/1.875V, which for a standard 3V battery is way too late. A fourth problem is emitting this warning from ->read_time: util-linux' hwclock will, in the absence of support for getting an interrupt when the seconds counter is updated, issue ioctl(RTC_RD_TIME) in a busy-loop until it sees a change in the seconds field. In that case, if the battery low bits are set (either genuinely, more than a minute after boot, due to the battery actually being low, or as above, bogusly shortly after boot), the kernel log is swamped with hundreds of identical warnings. Subsequent patches will add such bindings and driver support, and also proper support for RTC_VL_READ. For now, remove the broken warning. Signed-off-by: Rasmus Villemoes --- drivers/rtc/rtc-isl12022.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/rtc/rtc-isl12022.c b/drivers/rtc/rtc-isl12022.c index e68a79b5e00e..ebd66b835cef 100644 --- a/drivers/rtc/rtc-isl12022.c +++ b/drivers/rtc/rtc-isl12022.c @@ -141,12 +141,6 @@ static int isl12022_rtc_read_time(struct device *dev, struct rtc_time *tm) if (ret) return ret; - if (buf[ISL12022_REG_SR] & (ISL12022_SR_LBAT85 | ISL12022_SR_LBAT75)) { - dev_warn(dev, - "voltage dropped below %u%%, date and time is not reliable.\n", - buf[ISL12022_REG_SR] & ISL12022_SR_LBAT85 ? 85 : 75); - } - dev_dbg(dev, "raw data is sec=%02x, min=%02x, hr=%02x, mday=%02x, mon=%02x, year=%02x, wday=%02x, sr=%02x, int=%02x", buf[ISL12022_REG_SC],