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[209.132.180.67]) by mx.google.com with ESMTP id g8si12907488plp.325.2019.08.20.13.19.55; Tue, 20 Aug 2019 13:20:10 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730718AbfHTURv (ORCPT + 99 others); Tue, 20 Aug 2019 16:17:51 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:44169 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727358AbfHTURv (ORCPT ); Tue, 20 Aug 2019 16:17:51 -0400 X-Originating-IP: 90.65.161.137 Received: from localhost (lfbn-1-1545-137.w90-65.abo.wanadoo.fr [90.65.161.137]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id 0D46760007; Tue, 20 Aug 2019 20:17:44 +0000 (UTC) Date: Tue, 20 Aug 2019 22:17:44 +0200 From: Alexandre Belloni To: Ran Bi Cc: Rob Herring , Matthias Brugger , Alessandro Zummo , Mark Rutland , Mauro Carvalho Chehab , "David S . Miller" , Greg Kroah-Hartman , Jonathan Cameron , Linus Walleij , Nicolas Ferre , linux-rtc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, YT Shen , Eddie Huang , Yingjoe Chen , Flora Fu , Sean Wang Subject: Re: [PATCH v2 2/4] rtc: Add support for the MediaTek MT2712 RTC Message-ID: <20190820201744.GZ3545@piout.net> References: <20190801110122.26834-1-ran.bi@mediatek.com> <20190801110122.26834-3-ran.bi@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190801110122.26834-3-ran.bi@mediatek.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 01/08/2019 19:01:20+0800, Ran Bi wrote: > diff --git a/drivers/rtc/rtc-mt2712.c b/drivers/rtc/rtc-mt2712.c > new file mode 100644 > index 000000000000..1eb71ca64c2c > --- /dev/null > +++ b/drivers/rtc/rtc-mt2712.c > @@ -0,0 +1,444 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright (c) 2019 MediaTek Inc. > + * Author: Ran Bi > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define MTK_RTC_DEV KBUILD_MODNAME You probably shouldn't do that and have a static string for the driver name. I probably doesn't matter much though because DT is used to probe the driver. > +#define MT2712_WRTGR 0x0078 > + > +/* we map HW YEAR 0 to 2000 because 2000 is the leap year */ > +#define MT2712_MIN_YEAR 2000 > +#define MT2712_BASE_YEAR 1900 > +#define MT2712_MIN_YEAR_OFFSET (MT2712_MIN_YEAR - MT2712_BASE_YEAR) > +#define MT2712_MAX_YEAR_OFFSET (MT2712_MIN_YEAR_OFFSET + 127) > + All those defines are unecessary, see below. > +struct mt2712_rtc { > + struct device *dev; Looking at the code closely, it seems this is only used for debug and error messages. Maybe you could use rtc_dev->dev instead. > + struct rtc_device *rtc_dev; > + void __iomem *base; > + int irq; > + u8 irq_wake_enabled; > +}; > + > +static inline u32 mt2712_readl(struct mt2712_rtc *rtc, u32 reg) > +{ > + return readl(rtc->base + reg); > +} > + > +static inline void mt2712_writel(struct mt2712_rtc *rtc, u32 reg, u32 val) > +{ > + writel(val, rtc->base + reg); > +} > + > +static void mt2712_rtc_write_trigger(struct mt2712_rtc *rtc) > +{ > + unsigned long timeout = jiffies + HZ/10; > + > + mt2712_writel(rtc, MT2712_WRTGR, 1); > + while (1) { > + if (!(mt2712_readl(rtc, MT2712_BBPU) & MT2712_BBPU_CBUSY)) > + break; > + > + if (time_after(jiffies, timeout)) { > + dev_err(rtc->dev, "%s time out!\n", __func__); > + break; > + } > + cpu_relax(); > + } > +} > + > +static void mt2712_rtc_writeif_unlock(struct mt2712_rtc *rtc) > +{ > + mt2712_writel(rtc, MT2712_PROT, MT2712_PROT_UNLOCK1); > + mt2712_rtc_write_trigger(rtc); > + mt2712_writel(rtc, MT2712_PROT, MT2712_PROT_UNLOCK2); > + mt2712_rtc_write_trigger(rtc); > +} > + > +static irqreturn_t rtc_irq_handler_thread(int irq, void *data) > +{ > + struct mt2712_rtc *rtc = data; > + u16 irqsta, irqen; > + > + mutex_lock(&rtc->rtc_dev->ops_lock); > + > + irqsta = mt2712_readl(rtc, MT2712_IRQ_STA); Do you have to lock that read? Is the register cleared on read? > + if (irqsta & MT2712_IRQ_STA_AL) { > + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); > + irqen = irqsta & ~MT2712_IRQ_EN_AL; > + > + mt2712_writel(rtc, MT2712_IRQ_EN, irqen); > + mt2712_rtc_write_trigger(rtc); > + > + mutex_unlock(&rtc->rtc_dev->ops_lock); > + return IRQ_HANDLED; > + } > + > + mutex_unlock(&rtc->rtc_dev->ops_lock); > + return IRQ_NONE; > +} > + > +static void __mt2712_rtc_read_time(struct mt2712_rtc *rtc, > + struct rtc_time *tm, int *sec) > +{ > + tm->tm_sec = mt2712_readl(rtc, MT2712_TC_SEC) & MT2712_SEC_MASK; > + tm->tm_min = mt2712_readl(rtc, MT2712_TC_MIN) & MT2712_MIN_MASK; > + tm->tm_hour = mt2712_readl(rtc, MT2712_TC_HOU) & MT2712_HOU_MASK; > + tm->tm_mday = mt2712_readl(rtc, MT2712_TC_DOM) & MT2712_DOM_MASK; > + tm->tm_mon = mt2712_readl(rtc, MT2712_TC_MTH) & MT2712_MTH_MASK; > + tm->tm_year = mt2712_readl(rtc, MT2712_TC_YEA) & MT2712_YEA_MASK; > + > + *sec = mt2712_readl(rtc, MT2712_TC_SEC) & MT2712_SEC_MASK; > +} > + > +static int mt2712_rtc_read_time(struct device *dev, struct rtc_time *tm) > +{ > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + int sec; > + > + do { > + __mt2712_rtc_read_time(rtc, tm, &sec); > + } while (sec < tm->tm_sec); /* SEC has carried */ Shouldn't that be while (tm->tm_sec < sec)? > + > + /* HW register use 7 bits to store year data, minus > + * MT2712_MIN_YEAR_OFFSET brfore write year data to register, and plus > + * MT2712_MIN_YEAR_OFFSET back after read year from register > + */ > + tm->tm_year += MT2712_MIN_YEAR_OFFSET; Simply add 100 in __mt2712_rtc_read_time > + > + /* HW register start mon from one, but tm_mon start from zero. */ > + tm->tm_mon--; > + You can also do that in __mt2712_rtc_read_time. > + if (rtc_valid_tm(tm)) { This check is unnecessary, the validity is always checked by the core. > + dev_dbg(rtc->dev, "%s: invalid time %ptR\n", __func__, tm); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int mt2712_rtc_set_time(struct device *dev, struct rtc_time *tm) > +{ > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + > + if (tm->tm_year > MT2712_MAX_YEAR_OFFSET) { > + dev_dbg(rtc->dev, "Set year %d out of range. (%d - %d)\n", > + 1900 + tm->tm_year, 1900 + MT2712_MIN_YEAR_OFFSET, > + 1900 + MT2712_MAX_YEAR_OFFSET); > + return -EINVAL; > + } This check is unnecessary, see below. > + > + tm->tm_year -= MT2712_MIN_YEAR_OFFSET; > + tm->tm_mon++; You should probably avoid modifying tm, move the substraction and addition in the mt2712_writel calls. > + > + mt2712_writel(rtc, MT2712_TC_SEC, tm->tm_sec & MT2712_SEC_MASK); > + mt2712_writel(rtc, MT2712_TC_MIN, tm->tm_min & MT2712_MIN_MASK); > + mt2712_writel(rtc, MT2712_TC_HOU, tm->tm_hour & MT2712_HOU_MASK); > + mt2712_writel(rtc, MT2712_TC_DOM, tm->tm_mday & MT2712_DOM_MASK); > + mt2712_writel(rtc, MT2712_TC_MTH, tm->tm_mon & MT2712_MTH_MASK); > + mt2712_writel(rtc, MT2712_TC_YEA, tm->tm_year & MT2712_YEA_MASK); > + > + mt2712_rtc_write_trigger(rtc); > + > + return 0; > +} > + > +static int mt2712_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) > +{ > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + struct rtc_time *tm = &alm->time; > + u16 irqen; > + > + irqen = mt2712_readl(rtc, MT2712_IRQ_EN); > + alm->enabled = !!(irqen & MT2712_IRQ_EN_AL); > + > + tm->tm_sec = mt2712_readl(rtc, MT2712_AL_SEC) & MT2712_SEC_MASK; > + tm->tm_min = mt2712_readl(rtc, MT2712_AL_MIN) & MT2712_MIN_MASK; > + tm->tm_hour = mt2712_readl(rtc, MT2712_AL_HOU) & MT2712_HOU_MASK; > + tm->tm_mday = mt2712_readl(rtc, MT2712_AL_DOM) & MT2712_DOM_MASK; > + tm->tm_mon = mt2712_readl(rtc, MT2712_AL_MTH) & MT2712_MTH_MASK; > + tm->tm_year = mt2712_readl(rtc, MT2712_AL_YEA) & MT2712_YEA_MASK; > + > + tm->tm_year += MT2712_MIN_YEAR_OFFSET; > + tm->tm_mon--; > + > + if (rtc_valid_tm(tm)) { > + dev_dbg(rtc->dev, "%s: invalid alarm %ptR\n", __func__, tm); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int mt2712_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) > +{ > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + struct rtc_time *tm = &alm->time; > + u16 irqen; > + > + if (tm->tm_year > MT2712_MAX_YEAR_OFFSET) { > + dev_dbg(rtc->dev, "Set year %d out of range. (%d - %d)\n", > + 1900 + tm->tm_year, 1900 + MT2712_MIN_YEAR_OFFSET, > + 1900 + MT2712_MAX_YEAR_OFFSET); > + return -EINVAL; > + } > + Unnecessary check. > + dev_dbg(rtc->dev, "set al time: %ptR, alm en: %d\n", tm, alm->enabled); > + > + tm->tm_year -= MT2712_MIN_YEAR_OFFSET; > + tm->tm_mon++; > + > + irqen = mt2712_readl(rtc, MT2712_IRQ_EN) & ~(MT2712_IRQ_EN_ONESHOT_AL); > + mt2712_writel(rtc, MT2712_IRQ_EN, irqen); > + mt2712_rtc_write_trigger(rtc); > + > + mt2712_writel(rtc, MT2712_AL_SEC, > + (mt2712_readl(rtc, MT2712_AL_SEC) & ~(MT2712_SEC_MASK)) | > + (tm->tm_sec & MT2712_SEC_MASK)); > + mt2712_writel(rtc, MT2712_AL_MIN, > + (mt2712_readl(rtc, MT2712_AL_MIN) & ~(MT2712_MIN_MASK)) | > + (tm->tm_min & MT2712_MIN_MASK)); > + mt2712_writel(rtc, MT2712_AL_HOU, > + (mt2712_readl(rtc, MT2712_AL_HOU) & ~(MT2712_HOU_MASK)) | > + (tm->tm_hour & MT2712_HOU_MASK)); > + mt2712_writel(rtc, MT2712_AL_DOM, > + (mt2712_readl(rtc, MT2712_AL_DOM) & ~(MT2712_DOM_MASK)) | > + (tm->tm_mday & MT2712_DOM_MASK)); > + mt2712_writel(rtc, MT2712_AL_MTH, > + (mt2712_readl(rtc, MT2712_AL_MTH) & ~(MT2712_MTH_MASK)) | > + (tm->tm_mon & MT2712_MTH_MASK)); > + mt2712_writel(rtc, MT2712_AL_YEA, > + (mt2712_readl(rtc, MT2712_AL_YEA) & ~(MT2712_YEA_MASK)) | > + (tm->tm_year & MT2712_YEA_MASK)); > + > + mt2712_writel(rtc, MT2712_AL_MASK, MT2712_AL_MASK_DOW); /* mask DOW */ > + > + if (alm->enabled) { > + irqen = mt2712_readl(rtc, MT2712_IRQ_EN) | > + MT2712_IRQ_EN_ONESHOT_AL; > + mt2712_writel(rtc, MT2712_IRQ_EN, irqen); > + } else { > + irqen = mt2712_readl(rtc, MT2712_IRQ_EN) & > + ~(MT2712_IRQ_EN_ONESHOT_AL); > + mt2712_writel(rtc, MT2712_IRQ_EN, irqen); > + } > + mt2712_rtc_write_trigger(rtc); > + > + return 0; > +} > + > +/* Init RTC register */ > +static void mt2712_rtc_hw_init(struct mt2712_rtc *rtc) > +{ > + u32 p1, p2; > + > + mt2712_writel(rtc, MT2712_BBPU, MT2712_BBPU_KEY | MT2712_BBPU_RELOAD); > + > + mt2712_writel(rtc, MT2712_CII_EN, 0); > + mt2712_writel(rtc, MT2712_AL_MASK, 0); > + /* necessary before set MT2712_POWERKEY */ > + mt2712_writel(rtc, MT2712_CON0, 0x4848); > + mt2712_writel(rtc, MT2712_CON1, 0x0048); > + > + mt2712_rtc_write_trigger(rtc); > + > + mt2712_readl(rtc, MT2712_IRQ_STA); /* read clear */ > + > + p1 = mt2712_readl(rtc, MT2712_POWERKEY1); > + p2 = mt2712_readl(rtc, MT2712_POWERKEY2); > + if (p1 != MT2712_POWERKEY1_KEY || p2 != MT2712_POWERKEY2_KEY) > + dev_dbg(rtc->dev, "powerkey not set (lost power)\n"); > + This info is valuable, you should check that when reading the time and return -EINVAL if power was lost. > + /* RTC need POWERKEY1/2 match, then goto normal work mode */ > + mt2712_writel(rtc, MT2712_POWERKEY1, MT2712_POWERKEY1_KEY); > + mt2712_writel(rtc, MT2712_POWERKEY2, MT2712_POWERKEY2_KEY); This should be written when setting the time after power was lost. > + mt2712_rtc_write_trigger(rtc); > + > + mt2712_rtc_writeif_unlock(rtc); > +} > + > +static const struct rtc_class_ops mt2712_rtc_ops = { > + .read_time = mt2712_rtc_read_time, > + .set_time = mt2712_rtc_set_time, > + .read_alarm = mt2712_rtc_read_alarm, > + .set_alarm = mt2712_rtc_set_alarm, For proper operations, you should also provide the .alarm_irq_enable callback. > +}; > + > +static int mt2712_rtc_probe(struct platform_device *pdev) > +{ > + struct resource *res; > + struct mt2712_rtc *rtc; > + int ret; > + > + rtc = devm_kzalloc(&pdev->dev, sizeof(struct mt2712_rtc), GFP_KERNEL); > + if (!rtc) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + rtc->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(rtc->base)) > + return PTR_ERR(rtc->base); > + > + rtc->irq = platform_get_irq(pdev, 0); > + if (rtc->irq < 0) { > + dev_err(&pdev->dev, "No IRQ resource\n"); > + return rtc->irq; > + } > + > + rtc->dev = &pdev->dev; > + platform_set_drvdata(pdev, rtc); > + > + rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev); > + if (IS_ERR(rtc->rtc_dev)) > + return PTR_ERR(rtc->rtc_dev); > + > + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq, NULL, > + rtc_irq_handler_thread, > + IRQF_ONESHOT | IRQF_TRIGGER_LOW, > + dev_name(rtc->dev), rtc); > + if (ret) { > + dev_err(&pdev->dev, "Failed to request alarm IRQ: %d: %d\n", > + rtc->irq, ret); > + return ret; > + } > + > + /* rtc hw init */ > + mt2712_rtc_hw_init(rtc); > + > + device_init_wakeup(&pdev->dev, true); > + > + rtc->rtc_dev->ops = &mt2712_rtc_ops; If you set the range properly here using rtc_dev->range_min and rtc_dev->range_max, then the core will be able to do range checking and will also take care of the year offset/windowing calculations instead of having to hardcode that in the driver. > + > + ret = rtc_register_device(rtc->rtc_dev); > + if (ret) { > + dev_err(&pdev->dev, "register rtc device failed\n"); > + return ret; > + } > + > + return 0; > +} > + > +#ifdef CONFIG_PM_SLEEP > +static int mt2712_rtc_suspend(struct device *dev) > +{ > + int wake_status = 0; > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + > + if (device_may_wakeup(dev)) { > + wake_status = enable_irq_wake(rtc->irq); > + if (!wake_status) > + rtc->irq_wake_enabled = true; > + } > + > + return 0; > +} > + > +static int mt2712_rtc_resume(struct device *dev) > +{ > + int wake_status = 0; > + struct mt2712_rtc *rtc = dev_get_drvdata(dev); > + > + if (device_may_wakeup(dev) && rtc->irq_wake_enabled) { > + wake_status = disable_irq_wake(rtc->irq); > + if (!wake_status) > + rtc->irq_wake_enabled = false; > + } > + > + return 0; > +} > + > +static SIMPLE_DEV_PM_OPS(mt2712_pm_ops, mt2712_rtc_suspend, > + mt2712_rtc_resume); > +#endif > + > +static const struct of_device_id mt2712_rtc_of_match[] = { > + { .compatible = "mediatek,mt2712-rtc", }, > + { }, > +}; > + > +MODULE_DEVICE_TABLE(of, mt2712_rtc_of_match) > + > +static struct platform_driver mt2712_rtc_driver = { > + .driver = { > + .name = MTK_RTC_DEV, > + .of_match_table = mt2712_rtc_of_match, > + .pm = &mt2712_pm_ops, > + }, > + .probe = mt2712_rtc_probe, > +}; > + > +module_platform_driver(mt2712_rtc_driver); > + > +MODULE_DESCRIPTION("MediaTek MT2712 SoC based RTC Driver"); > +MODULE_AUTHOR("Ran Bi "); > +MODULE_LICENSE("GPL"); > -- > 2.21.0 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com