From patchwork Sun Dec 29 20:44:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Belloni X-Patchwork-Id: 11312455 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A71CE1395 for ; Sun, 29 Dec 2019 20:46:44 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 85657207E0 for ; Sun, 29 Dec 2019 20:46:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="q7aXXkOe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 85657207E0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5HIsRWF1CAc9/d0ipxQpFI2lYh7Nk6APvUdPGyuzrNU=; b=q7aXXkOe7GbDOr GcYMaylIvUB6DEpeotiwORK2ue+m5M5M7Eq2cxB75jDSnIQT+f8o/cy8oN+jyMTnRUBwiQmE2YLZR pbnIJwkP/vMxipH+9YlUKZKBq00nIzEjTZOtGKSRFau1mFXeLXBEuWKqoc+Oj8Gwib8D+8sy1ERHG vO3sAUtO5HRk0j2TiNtoouwpomKLHgHHcgt3gr1g1039pFbiIFZ2HPt7IyL828EBip38Kux9oKpmg DEfMHYHCb9FWGiWlW9ZJGkJK/x9YM+LMXkivAOp4IHlxX6A6Hp3JKAlmEkSraKE0o0JTcibOgovm4 CmYVN5H/+0ytaNdpsEVQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ilfSV-0002Xj-1i; Sun, 29 Dec 2019 20:46:43 +0000 Received: from relay4-d.mail.gandi.net ([217.70.183.196]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ilfRJ-0001aO-P0 for linux-arm-kernel@lists.infradead.org; Sun, 29 Dec 2019 20:45:32 +0000 X-Originating-IP: 92.184.100.83 Received: from localhost (unknown [92.184.100.83]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay4-d.mail.gandi.net (Postfix) with ESMTPSA id 897D9E0003; Sun, 29 Dec 2019 20:45:27 +0000 (UTC) From: Alexandre Belloni To: linux-rtc@vger.kernel.org Subject: [PATCH 7/9] rtc: at91rm9200: add correction support Date: Sun, 29 Dec 2019 21:44:19 +0100 Message-Id: <20191229204421.337612-7-alexandre.belloni@bootlin.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191229204421.337612-1-alexandre.belloni@bootlin.com> References: <20191229204421.337612-1-alexandre.belloni@bootlin.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191229_124530_135756_D7A25B43 X-CRM114-Status: GOOD ( 15.35 ) X-Spam-Score: -0.7 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [217.70.183.196 listed in list.dnswl.org] -0.0 RCVD_IN_MSPIKE_H3 RBL: Good reputation (+3) [217.70.183.196 listed in wl.mailspike.net] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eugen.Hristev@microchip.com, Alexandre Belloni , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The sama5d4 and sama5d2 RTCs are able to correct for imprecise crystals, up to 1953 ppm. Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-at91rm9200.c | 95 ++++++++++++++++++++++++++++++++++-- 1 file changed, 91 insertions(+), 4 deletions(-) diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c index 5e811e04cb21..fe4823e1fd60 100644 --- a/drivers/rtc/rtc-at91rm9200.c +++ b/drivers/rtc/rtc-at91rm9200.c @@ -36,6 +36,10 @@ #define AT91_RTC_UPDCAL BIT(1) /* Update Request Calendar Register */ #define AT91_RTC_MR 0x04 /* Mode Register */ +#define AT91_RTC_HRMOD BIT(0) /* 12/24 hour mode */ +#define AT91_RTC_NEGPPM BIT(4) /* Negative PPM correction */ +#define AT91_RTC_CORRECTION GENMASK(14, 8) /* Slow clock correction */ +#define AT91_RTC_HIGHPPM BIT(15) /* High PPM correction */ #define AT91_RTC_TIMR 0x08 /* Time Register */ #define AT91_RTC_SEC GENMASK(6, 0) /* Current Second */ @@ -77,6 +81,9 @@ #define AT91_RTC_NVTIMALR BIT(2) /* Non valid Time Alarm */ #define AT91_RTC_NVCALALR BIT(3) /* Non valid Calendar Alarm */ +#define AT91_RTC_CORR_STEP 1526 +#define AT91_RTC_CORR_STEP_HIGH 30516 + #define at91_rtc_read(field) \ readl_relaxed(at91_rtc_regs + field) #define at91_rtc_write(field, val) \ @@ -84,6 +91,7 @@ struct at91_rtc_config { bool use_shadow_imr; + bool has_correction; }; static const struct at91_rtc_config *at91_rtc_config; @@ -293,6 +301,66 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) return 0; } +static int at91_rtc_readoffset(struct device *dev, long *offset) +{ + u32 mr = at91_rtc_read(AT91_RTC_MR); + long val = FIELD_GET(AT91_RTC_CORRECTION, mr); + + if (!val) { + *offset = 0; + return 0; + } + + val++; + + if (mr & AT91_RTC_NEGPPM) + val = -val; + + if (mr & AT91_RTC_HIGHPPM) + *offset = val * AT91_RTC_CORR_STEP_HIGH; + else + *offset = val * AT91_RTC_CORR_STEP; + + return 0; +} + +static int at91_rtc_setoffset(struct device *dev, long offset) +{ + long mode0, mode1, error0, error1; + u32 mr; + + + if (offset > AT91_RTC_CORR_STEP_HIGH * 128) + return -ERANGE; + if (offset < AT91_RTC_CORR_STEP_HIGH * -128) + return -ERANGE; + + mr = at91_rtc_read(AT91_RTC_MR); + mr &= ~(AT91_RTC_NEGPPM | AT91_RTC_CORRECTION | AT91_RTC_HIGHPPM); + + if (offset < 0) { + mr |= AT91_RTC_NEGPPM; + offset = -offset; + } + + mode0 = DIV_ROUND_CLOSEST(offset, AT91_RTC_CORR_STEP); + mode1 = DIV_ROUND_CLOSEST(offset, AT91_RTC_CORR_STEP_HIGH); + + error0 = abs(offset - (mode0 * AT91_RTC_CORR_STEP)); + error1 = abs(offset - (mode1 * AT91_RTC_CORR_STEP_HIGH)); + + if (mode0 > 128 || error0 > error1) { + mr |= AT91_RTC_HIGHPPM; + mr |= FIELD_PREP(AT91_RTC_CORRECTION, mode1 - 1); + } else { + mr |= FIELD_PREP(AT91_RTC_CORRECTION, mode0 - 1); + } + + at91_rtc_write(AT91_RTC_MR, mr); + + return 0; +} + /* * IRQ handler for the RTC */ @@ -343,6 +411,10 @@ static const struct at91_rtc_config at91sam9x5_config = { .use_shadow_imr = true, }; +static const struct at91_rtc_config sama5d4_config = { + .has_correction = true, +}; + static const struct of_device_id at91_rtc_dt_ids[] = { { .compatible = "atmel,at91rm9200-rtc", @@ -352,10 +424,10 @@ static const struct of_device_id at91_rtc_dt_ids[] = { .data = &at91sam9x5_config, }, { .compatible = "atmel,sama5d4-rtc", - .data = &at91rm9200_config, + .data = &sama5d4_config, }, { .compatible = "atmel,sama5d2-rtc", - .data = &at91rm9200_config, + .data = &sama5d4_config, }, { /* sentinel */ } @@ -370,6 +442,16 @@ static const struct rtc_class_ops at91_rtc_ops = { .alarm_irq_enable = at91_rtc_alarm_irq_enable, }; +static const struct rtc_class_ops sama5d4_rtc_ops = { + .read_time = at91_rtc_readtime, + .set_time = at91_rtc_settime, + .read_alarm = at91_rtc_readalarm, + .set_alarm = at91_rtc_setalarm, + .alarm_irq_enable = at91_rtc_alarm_irq_enable, + .set_offset = at91_rtc_setoffset, + .read_offset = at91_rtc_readoffset, +}; + /* * Initialize and install RTC driver */ @@ -416,7 +498,8 @@ static int __init at91_rtc_probe(struct platform_device *pdev) } at91_rtc_write(AT91_RTC_CR, 0); - at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */ + at91_rtc_write(AT91_RTC_MR, + at91_rtc_read(AT91_RTC_MR) & ~AT91_RTC_HRMOD); /* Disable all interrupts */ at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | @@ -437,7 +520,11 @@ static int __init at91_rtc_probe(struct platform_device *pdev) if (!device_can_wakeup(&pdev->dev)) device_init_wakeup(&pdev->dev, 1); - rtc->ops = &at91_rtc_ops; + if (at91_rtc_config->has_correction) + rtc->ops = &sama5d4_rtc_ops; + else + rtc->ops = &at91_rtc_ops; + rtc->range_min = RTC_TIMESTAMP_BEGIN_1900; rtc->range_max = RTC_TIMESTAMP_END_2099; ret = rtc_register_device(rtc);