From patchwork Wed Jul 5 17:43:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Caron X-Patchwork-Id: 13302529 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7C1E5EB64DA for ; Wed, 5 Jul 2023 17:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=b+NAQoXRvTjixU5GMUbYQmXOARfPYirZKj8DfllFxGs=; b=Q1ZaXJCslMtz4M 84ur+/bfFUhKgb09fuIpyLuqPlA+4h0P3JpwigjLm9/fExwBLJyoqCcuFQeMi4TrPoXJ5VPA4Ev/O HuFqftu7N3jxVpzqRU1iT9Ju356SeFPPRfVbJbd66dUuD1n7be3OoU2zgkyaIos4nO3HwrywmLLmR jYaTeY4CuGXJUku5hLNSeEy8KEW2Odks8AUzGzXQ2S1yShMhTWRs27XbSvSxhXl9mQq5QGuzY8c6A TrVijvGfyP19XKrnditObV0j2K5iYVAoq9h0K/h1hAKO9i4v5cZ3++5c1kxK6Veyd8OU21RSBkjv3 H73xpbkEVu2+VKnFcRbA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qH6Y0-00GeXe-0t; Wed, 05 Jul 2023 17:44:12 +0000 Received: from mx08-00178001.pphosted.com ([91.207.212.93] helo=mx07-00178001.pphosted.com) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qH6Xu-00GeUs-10 for linux-arm-kernel@lists.infradead.org; Wed, 05 Jul 2023 17:44:08 +0000 Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 365F65mL010379; Wed, 5 Jul 2023 19:44:04 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=selector1; bh=3uBLJmxq5VVWC2o5xkCW/MuK8POUJa1lY65SLOrbAlI=; b=edBzDynwoKrL06YBlXLhYm9JjqJ3LfQXKjC8Z+aCySbYs5mNOoPIM0a2Gp2wTdeerB8H skHCanwEAc81hc6V1rEhBuhUn+cqopwkUSErmlOUcx8VBlWGzLLCBy12qMHSdESl9wpp yPpqdWACKo5bpTDboaCQSdpmzI0tXNgzDYKOROZZlQlcsncceBV3Xrs7Xs2CMpmqrOZC CxeLQ+ZERe20AvJy4yvPSULdS7casrW39ormhchu0GL5IGsSP/DJ7MaFxyyJxai6cgKq XO8ryjCl9n12v5ZKkRBgn8c7JEBngZ+FMLfexD9ZSJVWTQrksT4mUrtFS4gyOlSVgRpU bg== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3rn7wp2bsg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 05 Jul 2023 19:44:04 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id E6C9410005E; Wed, 5 Jul 2023 19:44:03 +0200 (CEST) Received: from Webmail-eu.st.com (shfdag1node1.st.com [10.75.129.69]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id DF420252250; Wed, 5 Jul 2023 19:44:03 +0200 (CEST) Received: from localhost (10.201.20.168) by SHFDAG1NODE1.st.com (10.75.129.69) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Wed, 5 Jul 2023 19:44:03 +0200 From: Valentin Caron To: Alexandre Belloni , Alessandro Zummo CC: Alexandre Torgue , Antonio Borneo , Christophe Guibout , Gabriel Fernandez , , , , , Valentin Caron Subject: [PATCH v2 2/7] rtc: stm32: don't stop time counter if not needed Date: Wed, 5 Jul 2023 19:43:52 +0200 Message-ID: <20230705174357.353616-3-valentin.caron@foss.st.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230705174357.353616-1-valentin.caron@foss.st.com> References: <20230705174357.353616-1-valentin.caron@foss.st.com> MIME-Version: 1.0 X-Originating-IP: [10.201.20.168] X-ClientProxiedBy: SHFCAS1NODE2.st.com (10.75.129.73) To SHFDAG1NODE1.st.com (10.75.129.69) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-07-05_09,2023-07-05_01,2023-05-22_02 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230705_104406_621323_EEF2313C X-CRM114-Status: GOOD ( 21.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Antonio Borneo RTC counters are stopped when INIT bit in ISR register is set and start counting from the (eventual) new value when INIT is reset. In stm32_rtc_init(), called during probe, the INIT bit is set to program the prescaler and the 24h mode. This halts the RTC counter at each probe tentative causing the RTC time to loose from 0.3s to 0.8s at each kernel boot. If the RTC is battery powered, both prescaler value and 24h mode are kept during power cycle and there is no need to program them again. Check if the desired prescaler value and the 24h mode are already programmed, then skip reprogramming them to avoid halting the time counter. Signed-off-by: Antonio Borneo Signed-off-by: Valentin Caron --- drivers/rtc/rtc-stm32.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c index abb77ad774a1..bd7a59a07537 100644 --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -628,7 +628,7 @@ static int stm32_rtc_init(struct platform_device *pdev, const struct stm32_rtc_registers *regs = &rtc->data->regs; unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr; unsigned int rate; - int ret = 0; + int ret; rate = clk_get_rate(rtc->rtc_ck); @@ -656,6 +656,20 @@ static int stm32_rtc_init(struct platform_device *pdev, "fast" : "slow"); } + cr = readl_relaxed(rtc->base + regs->cr); + + prer = readl_relaxed(rtc->base + regs->prer); + prer &= STM32_RTC_PRER_PRED_S | STM32_RTC_PRER_PRED_A; + + pred_s = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & + STM32_RTC_PRER_PRED_S; + pred_a = (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & + STM32_RTC_PRER_PRED_A; + + /* quit if there is nothing to initialize */ + if ((cr & STM32_RTC_CR_FMT) == 0 && prer == (pred_s | pred_a)) + return 0; + stm32_rtc_wpr_unlock(rtc); ret = stm32_rtc_enter_init_mode(rtc); @@ -665,13 +679,10 @@ static int stm32_rtc_init(struct platform_device *pdev, goto end; } - prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S; - writel_relaxed(prer, rtc->base + regs->prer); - prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A; - writel_relaxed(prer, rtc->base + regs->prer); + writel_relaxed(pred_s, rtc->base + regs->prer); + writel_relaxed(pred_a | pred_s, rtc->base + regs->prer); /* Force 24h time format */ - cr = readl_relaxed(rtc->base + regs->cr); cr &= ~STM32_RTC_CR_FMT; writel_relaxed(cr, rtc->base + regs->cr);