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: 1216153 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-rtc-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bootlin.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47mCHv0HLKz9sPW for ; Mon, 30 Dec 2019 07:45:31 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726867AbfL2Upa (ORCPT ); Sun, 29 Dec 2019 15:45:30 -0500 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:55195 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726444AbfL2Up3 (ORCPT ); Sun, 29 Dec 2019 15:45:29 -0500 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 Cc: Nicolas Ferre , Eugen.Hristev@microchip.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Alexandre Belloni 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 Sender: linux-rtc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rtc@vger.kernel.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);