/* * Driver for MediaTek SoC based RTC * * Copyright (C) 2017 Sean Wang * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #define MTK_RTC_DEV KBUILD_MODNAME #define MTK_RTC_PWRCHK1 0x4 #define RTC_PWRCHK1_MAGIC 0xc6 #define MTK_RTC_PWRCHK2 0x8 #define RTC_PWRCHK2_MAGIC 0x9a #define MTK_RTC_KEY 0xc #define RTC_KEY_MAGIC 0x59 #define MTK_RTC_PROT1 0x10 #define RTC_PROT1_MAGIC 0xa3 #define MTK_RTC_PROT2 0x14 #define RTC_PROT2_MAGIC 0x57 #define MTK_RTC_PROT3 0x18 #define RTC_PROT3_MAGIC 0x67 #define MTK_RTC_PROT4 0x1c #define RTC_PROT4_MAGIC 0xd2 #define MTK_RTC_CTL 0x20 #define RTC_RC_STOP BIT(0) #define MTK_RTC_DEBNCE 0x2c #define RTC_DEBNCE_MASK GENMASK(2, 0) #define MTK_RTC_INT 0x30 #define RTC_INT_AL_STA BIT(4) /* * Ranges from 0x40 to 0x78 provide RTC time setup for year, month, * day of month, day of week, hour, minute and second. */ #define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20)) #define MTK_RTC_AL_CTL 0x7c #define RTC_AL_EN BIT(0) #define RTC_AL_ALL GENMASK(7, 0) /* * The offset is used in the translation for the year between in struct * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA) */ #define MTK_RTC_TM_YR_OFFSET 100 /* * The lowest value for the valid tm_year. RTC hardware would take incorrectly * tm_year 100 as not a leap year and thus it is also required being excluded * from the valid options. */ #define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1) /* * The most year the RTC can hold is 99 and the next to 99 in year register * would be wraparound to 0, for MT7622. */ #define MTK_RTC_HW_YR_LIMIT 99 /* The highest value for the valid tm_year */ #define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT) /* Simple macro helps to check whether the hardware supports the tm_year */ #define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \ (_y) <= MTK_RTC_TM_YR_H) /* Types of the function the RTC provides are time counter and alarm. */ enum { MTK_TC, MTK_AL, }; /* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */ enum { MTK_YEA, MTK_MON, MTK_DOM, MTK_DOW, MTK_HOU, MTK_MIN, MTK_SEC }; struct mtk_rtc { struct rtc_device *rtc; void __iomem *base; int irq; struct clk *clk; }; static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val) { writel_relaxed(val, rtc->base + reg); } static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg) { return readl_relaxed(rtc->base + reg); } static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set) { u32 val; val = mtk_r32(rtc, reg); val &= ~mask; val |= set; mtk_w32(rtc, reg, val); } static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val) { mtk_rmw(rtc, reg, 0, val); } static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val) { mtk_rmw(rtc, reg, val, 0); } static void mtk_rtc_hw_init(struct mtk_rtc *hw) { /* The setup of the init sequence is for allowing RTC got to work */ mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC); mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC); mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC); mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC); mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC); mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC); mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC); mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0); mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); } static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, int time_alarm) { u32 year, mon, mday, wday, hour, min, sec; /* * Read again until the field of the second is not changed which * ensures all fields in the consistent state. Note that MTK_SEC must * be read first. In this way, it guarantees the others remain not * changed when the results for two MTK_SEC consecutive reads are same. */ do { sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)); min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN)); hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU)); wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW)); mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM)); mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON)); year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA)); } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC))); tm->tm_sec = sec; tm->tm_min = min; tm->tm_hour = hour; tm->tm_wday = wday; tm->tm_mday = mday; tm->tm_mon = mon - 1; /* Rebase to the absolute year which userspace queries */ tm->tm_year = year + MTK_RTC_TM_YR_OFFSET; } static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm, int time_alarm) { u32 year; /* Rebase to the relative year which RTC hardware requires */ year = tm->tm_year - MTK_RTC_TM_YR_OFFSET; mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min); mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec); } static irqreturn_t mtk_rtc_alarmirq(int irq, void *id) { struct mtk_rtc *hw = (struct mtk_rtc *)id; u32 irq_sta; irq_sta = mtk_r32(hw, MTK_RTC_INT); if (irq_sta & RTC_INT_AL_STA) { /* Stop alarm also implicitly disables the alarm interrupt */ mtk_w32(hw, MTK_RTC_AL_CTL, 0); rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF); /* Ack alarm interrupt status */ mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA); return IRQ_HANDLED; } return IRQ_NONE; } static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm) { struct mtk_rtc *hw = dev_get_drvdata(dev); mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC); return rtc_valid_tm(tm); } static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm) { struct mtk_rtc *hw = dev_get_drvdata(dev); if (!MTK_RTC_TM_YR_VALID(tm->tm_year)) return -EINVAL; /* Stop time counter before setting a new one*/ mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP); mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC); /* Restart the time counter */ mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP); return 0; } static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm) { struct mtk_rtc *hw = dev_get_drvdata(dev); struct rtc_time *alrm_tm = &wkalrm->time; mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL); wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN); wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA); return 0; } static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm) { struct mtk_rtc *hw = dev_get_drvdata(dev); struct rtc_time *alrm_tm = &wkalrm->time; if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year)) return -EINVAL; /* * Stop the alarm also implicitly including disables interrupt before * setting a new one. */ mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN); /* * Avoid contention between mtk_rtc_setalarm and IRQ handler so that * disabling the interrupt and awaiting for pending IRQ handler to * complete. */ synchronize_irq(hw->irq); mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL); /* Restart the alarm with the new setup */ mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL); return 0; } static const struct rtc_class_ops mtk_rtc_ops = { .read_time = mtk_rtc_gettime, .set_time = mtk_rtc_settime, .read_alarm = mtk_rtc_getalarm, .set_alarm = mtk_rtc_setalarm, }; static const struct of_device_id mtk_rtc_match[] = { { .compatible = "mediatek,mt7622-rtc" }, { .compatible = "mediatek,soc-rtc" }, {}, }; static int mtk_rtc_probe(struct platform_device *pdev) { struct mtk_rtc *hw; struct resource *res; int ret; hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL); if (!hw) return -ENOMEM; platform_set_drvdata(pdev, hw); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); hw->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(hw->base)) return PTR_ERR(hw->base); hw->clk = devm_clk_get(&pdev->dev, "rtc"); if (IS_ERR(hw->clk)) { dev_err(&pdev->dev, "No clock\n"); return PTR_ERR(hw->clk); } ret = clk_prepare_enable(hw->clk); if (ret) return ret; hw->irq = platform_get_irq(pdev, 0); if (hw->irq < 0) { dev_err(&pdev->dev, "No IRQ resource\n"); ret = hw->irq; goto err; } ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq, 0, dev_name(&pdev->dev), hw); if (ret) { dev_err(&pdev->dev, "Can't request IRQ\n"); goto err; } mtk_rtc_hw_init(hw); device_init_wakeup(&pdev->dev, true); hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &mtk_rtc_ops, THIS_MODULE); if (IS_ERR(hw->rtc)) { ret = PTR_ERR(hw->rtc); dev_err(&pdev->dev, "Unable to register device\n"); goto err; } return 0; err: clk_disable_unprepare(hw->clk); return ret; } static int mtk_rtc_remove(struct platform_device *pdev) { struct mtk_rtc *hw = platform_get_drvdata(pdev); clk_disable_unprepare(hw->clk); return 0; } #ifdef CONFIG_PM_SLEEP static int mtk_rtc_suspend(struct device *dev) { struct mtk_rtc *hw = dev_get_drvdata(dev); if (device_may_wakeup(dev)) enable_irq_wake(hw->irq); return 0; } static int mtk_rtc_resume(struct device *dev) { struct mtk_rtc *hw = dev_get_drvdata(dev); if (device_may_wakeup(dev)) disable_irq_wake(hw->irq); return 0; } static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume); #define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops) #else /* CONFIG_PM */ #define MTK_RTC_PM_OPS NULL #endif /* CONFIG_PM */ static struct platform_driver mtk_rtc_driver = { .probe = mtk_rtc_probe, .remove = mtk_rtc_remove, .driver = { .name = MTK_RTC_DEV, .of_match_table = mtk_rtc_match, .pm = MTK_RTC_PM_OPS, }, }; module_platform_driver(mtk_rtc_driver); MODULE_DESCRIPTION("MediaTek SoC based RTC Driver"); MODULE_AUTHOR("Sean Wang "); MODULE_LICENSE("GPL");