// SPDX-License-Identifier: GPL-2.0-or-later /* * Real Time Clock interface for Linux on Atmel AT91RM9200 * * Copyright (C) 2002 Rick Bronson * * Converted to RTC class model by Andrew Victor * * Ported to Linux 2.6 by Steven Scholz * Based on s3c2410-rtc.c Simtec Electronics * * Based on sa1100-rtc.c by Nils Faerber * Based on rtc.c by Paul Gortmaker */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define AT91_RTC_CR 0x00 /* Control Register */ #define AT91_RTC_UPDTIM BIT(0) /* Update Request Time Register */ #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 */ #define AT91_RTC_MIN GENMASK(14, 8) /* Current Minute */ #define AT91_RTC_HOUR GENMASK(21, 16) /* Current Hour */ #define AT91_RTC_AMPM BIT(22) /* Ante Meridiem Post Meridiem Indicator */ #define AT91_RTC_CALR 0x0c /* Calendar Register */ #define AT91_RTC_CENT GENMASK(6, 0) /* Current Century */ #define AT91_RTC_YEAR GENMASK(15, 8) /* Current Year */ #define AT91_RTC_MONTH GENMASK(20, 16) /* Current Month */ #define AT91_RTC_DAY GENMASK(23, 21) /* Current Day */ #define AT91_RTC_DATE GENMASK(29, 24) /* Current Date */ #define AT91_RTC_TIMALR 0x10 /* Time Alarm Register */ #define AT91_RTC_SECEN BIT(7) /* Second Alarm Enable */ #define AT91_RTC_MINEN BIT(15) /* Minute Alarm Enable */ #define AT91_RTC_HOUREN BIT(23) /* Hour Alarm Enable */ #define AT91_RTC_CALALR 0x14 /* Calendar Alarm Register */ #define AT91_RTC_MTHEN BIT(23) /* Month Alarm Enable */ #define AT91_RTC_DATEEN BIT(31) /* Date Alarm Enable */ #define AT91_RTC_SR 0x18 /* Status Register */ #define AT91_RTC_ACKUPD BIT(0) /* Acknowledge for Update */ #define AT91_RTC_ALARM BIT(1) /* Alarm Flag */ #define AT91_RTC_SECEV BIT(2) /* Second Event */ #define AT91_RTC_TIMEV BIT(3) /* Time Event */ #define AT91_RTC_CALEV BIT(4) /* Calendar Event */ #define AT91_RTC_SCCR 0x1c /* Status Clear Command Register */ #define AT91_RTC_IER 0x20 /* Interrupt Enable Register */ #define AT91_RTC_IDR 0x24 /* Interrupt Disable Register */ #define AT91_RTC_IMR 0x28 /* Interrupt Mask Register */ #define AT91_RTC_VER 0x2c /* Valid Entry Register */ #define AT91_RTC_NVTIM BIT(0) /* Non valid Time */ #define AT91_RTC_NVCAL BIT(1) /* Non valid Calendar */ #define AT91_RTC_NVTIMALR BIT(2) /* Non valid Time Alarm */ #define AT91_RTC_NVCALALR BIT(3) /* Non valid Calendar Alarm */ #define AT91_RTC_CORR_DIVIDEND 3906000 #define AT91_RTC_CORR_LOW_RATIO 20 #define at91_rtc_read(field) \ readl_relaxed(at91_rtc_regs + field) #define at91_rtc_write(field, val) \ writel_relaxed((val), at91_rtc_regs + field) struct at91_rtc_config { bool use_shadow_imr; bool has_correction; }; static const struct at91_rtc_config *at91_rtc_config; static DECLARE_COMPLETION(at91_rtc_updated); static DECLARE_COMPLETION(at91_rtc_upd_rdy); static void __iomem *at91_rtc_regs; static int irq; static DEFINE_SPINLOCK(at91_rtc_lock); static u32 at91_rtc_shadow_imr; static bool suspended; static DEFINE_SPINLOCK(suspended_lock); static unsigned long cached_events; static u32 at91_rtc_imr; static struct clk *sclk; static void at91_rtc_write_ier(u32 mask) { unsigned long flags; spin_lock_irqsave(&at91_rtc_lock, flags); at91_rtc_shadow_imr |= mask; at91_rtc_write(AT91_RTC_IER, mask); spin_unlock_irqrestore(&at91_rtc_lock, flags); } static void at91_rtc_write_idr(u32 mask) { unsigned long flags; spin_lock_irqsave(&at91_rtc_lock, flags); at91_rtc_write(AT91_RTC_IDR, mask); /* * Register read back (of any RTC-register) needed to make sure * IDR-register write has reached the peripheral before updating * shadow mask. * * Note that there is still a possibility that the mask is updated * before interrupts have actually been disabled in hardware. The only * way to be certain would be to poll the IMR-register, which is * the very register we are trying to emulate. The register read back * is a reasonable heuristic. */ at91_rtc_read(AT91_RTC_SR); at91_rtc_shadow_imr &= ~mask; spin_unlock_irqrestore(&at91_rtc_lock, flags); } static u32 at91_rtc_read_imr(void) { unsigned long flags; u32 mask; if (at91_rtc_config->use_shadow_imr) { spin_lock_irqsave(&at91_rtc_lock, flags); mask = at91_rtc_shadow_imr; spin_unlock_irqrestore(&at91_rtc_lock, flags); } else { mask = at91_rtc_read(AT91_RTC_IMR); } return mask; } /* * Decode time/date into rtc_time structure */ static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg, struct rtc_time *tm) { unsigned int time, date; /* must read twice in case it changes */ do { time = at91_rtc_read(timereg); date = at91_rtc_read(calreg); } while ((time != at91_rtc_read(timereg)) || (date != at91_rtc_read(calreg))); tm->tm_sec = bcd2bin(FIELD_GET(AT91_RTC_SEC, time)); tm->tm_min = bcd2bin(FIELD_GET(AT91_RTC_MIN, time)); tm->tm_hour = bcd2bin(FIELD_GET(AT91_RTC_HOUR, time)); /* * The Calendar Alarm register does not have a field for * the year - so these will return an invalid value. */ tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */ tm->tm_year += bcd2bin(FIELD_GET(AT91_RTC_YEAR, date)); /* year */ tm->tm_wday = bcd2bin(FIELD_GET(AT91_RTC_DAY, date)) - 1; /* day of the week [0-6], Sunday=0 */ tm->tm_mon = bcd2bin(FIELD_GET(AT91_RTC_MONTH, date)) - 1; tm->tm_mday = bcd2bin(FIELD_GET(AT91_RTC_DATE, date)); } /* * Read current time and date in RTC */ static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm) { at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm); tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year); tm->tm_year = tm->tm_year - 1900; dev_dbg(dev, "%s(): %ptR\n", __func__, tm); return 0; } /* * Set current time and date in RTC */ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm) { unsigned long cr; dev_dbg(dev, "%s(): %ptR\n", __func__, tm); wait_for_completion(&at91_rtc_upd_rdy); /* Stop Time/Calendar from counting */ cr = at91_rtc_read(AT91_RTC_CR); at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM); at91_rtc_write_ier(AT91_RTC_ACKUPD); wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */ at91_rtc_write_idr(AT91_RTC_ACKUPD); at91_rtc_write(AT91_RTC_TIMR, FIELD_PREP(AT91_RTC_SEC, bin2bcd(tm->tm_sec)) | FIELD_PREP(AT91_RTC_MIN, bin2bcd(tm->tm_min)) | FIELD_PREP(AT91_RTC_HOUR, bin2bcd(tm->tm_hour))); at91_rtc_write(AT91_RTC_CALR, FIELD_PREP(AT91_RTC_CENT, bin2bcd((tm->tm_year + 1900) / 100)) | FIELD_PREP(AT91_RTC_YEAR, bin2bcd(tm->tm_year % 100)) | FIELD_PREP(AT91_RTC_MONTH, bin2bcd(tm->tm_mon + 1)) | FIELD_PREP(AT91_RTC_DAY, bin2bcd(tm->tm_wday + 1)) | FIELD_PREP(AT91_RTC_DATE, bin2bcd(tm->tm_mday))); /* Restart Time/Calendar */ cr = at91_rtc_read(AT91_RTC_CR); at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_SECEV); at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM)); at91_rtc_write_ier(AT91_RTC_SECEV); return 0; } /* * Read alarm time and date in RTC */ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rtc_time *tm = &alrm->time; at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm); tm->tm_year = -1; alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM) ? 1 : 0; dev_dbg(dev, "%s(): %ptR %sabled\n", __func__, tm, alrm->enabled ? "en" : "dis"); return 0; } /* * Set alarm time and date in RTC */ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) { struct rtc_time tm = alrm->time; at91_rtc_write_idr(AT91_RTC_ALARM); at91_rtc_write(AT91_RTC_TIMALR, FIELD_PREP(AT91_RTC_SEC, bin2bcd(alrm->time.tm_sec)) | FIELD_PREP(AT91_RTC_MIN, bin2bcd(alrm->time.tm_min)) | FIELD_PREP(AT91_RTC_HOUR, bin2bcd(alrm->time.tm_hour)) | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN); at91_rtc_write(AT91_RTC_CALALR, FIELD_PREP(AT91_RTC_MONTH, bin2bcd(alrm->time.tm_mon + 1)) | FIELD_PREP(AT91_RTC_DATE, bin2bcd(alrm->time.tm_mday)) | AT91_RTC_DATEEN | AT91_RTC_MTHEN); if (alrm->enabled) { at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); at91_rtc_write_ier(AT91_RTC_ALARM); } dev_dbg(dev, "%s(): %ptR\n", __func__, &tm); return 0; } static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled); if (enabled) { at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); at91_rtc_write_ier(AT91_RTC_ALARM); } else at91_rtc_write_idr(AT91_RTC_ALARM); 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)) val *= AT91_RTC_CORR_LOW_RATIO; *offset = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, val); return 0; } static int at91_rtc_setoffset(struct device *dev, long offset) { long corr; u32 mr; if (offset > AT91_RTC_CORR_DIVIDEND / 2) return -ERANGE; if (offset < -AT91_RTC_CORR_DIVIDEND / 2) 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; else offset = -offset; /* offset less than 764 ppb, disable correction*/ if (offset < 764) { at91_rtc_write(AT91_RTC_MR, mr & ~AT91_RTC_NEGPPM); return 0; } /* * 29208 ppb is the perfect cutoff between low range and high range * low range values are never better than high range value after that. */ if (offset < 29208) { corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset * AT91_RTC_CORR_LOW_RATIO); } else { corr = DIV_ROUND_CLOSEST(AT91_RTC_CORR_DIVIDEND, offset); mr |= AT91_RTC_HIGHPPM; } if (corr > 128) corr = 128; mr |= FIELD_PREP(AT91_RTC_CORRECTION, corr - 1); at91_rtc_write(AT91_RTC_MR, mr); return 0; } /* * IRQ handler for the RTC */ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id) { struct platform_device *pdev = dev_id; struct rtc_device *rtc = platform_get_drvdata(pdev); unsigned int rtsr; unsigned long events = 0; int ret = IRQ_NONE; spin_lock(&suspended_lock); rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr(); if (rtsr) { /* this interrupt is shared! Is it ours? */ if (rtsr & AT91_RTC_ALARM) events |= (RTC_AF | RTC_IRQF); if (rtsr & AT91_RTC_SECEV) { complete(&at91_rtc_upd_rdy); at91_rtc_write_idr(AT91_RTC_SECEV); } if (rtsr & AT91_RTC_ACKUPD) complete(&at91_rtc_updated); at91_rtc_write(AT91_RTC_SCCR, rtsr); /* clear status reg */ if (!suspended) { rtc_update_irq(rtc, 1, events); dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__, events >> 8, events & 0x000000FF); } else { cached_events |= events; at91_rtc_write_idr(at91_rtc_imr); pm_system_wakeup(); } ret = IRQ_HANDLED; } spin_unlock(&suspended_lock); return ret; } static const struct at91_rtc_config at91rm9200_config = { }; 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", .data = &at91rm9200_config, }, { .compatible = "atmel,at91sam9x5-rtc", .data = &at91sam9x5_config, }, { .compatible = "atmel,sama5d4-rtc", .data = &sama5d4_config, }, { .compatible = "atmel,sama5d2-rtc", .data = &sama5d4_config, }, { .compatible = "microchip,sam9x60-rtc", .data = &sama5d4_config, }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids); static const struct rtc_class_ops at91_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, }; 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 */ static int __init at91_rtc_probe(struct platform_device *pdev) { struct rtc_device *rtc; struct resource *regs; int ret = 0; at91_rtc_config = of_device_get_match_data(&pdev->dev); if (!at91_rtc_config) return -ENODEV; regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) { dev_err(&pdev->dev, "no mmio resource defined\n"); return -ENXIO; } irq = platform_get_irq(pdev, 0); if (irq < 0) return -ENXIO; at91_rtc_regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs)); if (!at91_rtc_regs) { dev_err(&pdev->dev, "failed to map registers, aborting.\n"); return -ENOMEM; } rtc = devm_rtc_allocate_device(&pdev->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(pdev, rtc); sclk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(sclk)) return PTR_ERR(sclk); ret = clk_prepare_enable(sclk); if (ret) { dev_err(&pdev->dev, "Could not enable slow clock\n"); return ret; } at91_rtc_write(AT91_RTC_CR, 0); 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 | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV); ret = devm_request_irq(&pdev->dev, irq, at91_rtc_interrupt, IRQF_SHARED | IRQF_COND_SUSPEND, "at91_rtc", pdev); if (ret) { dev_err(&pdev->dev, "IRQ %d already in use.\n", irq); goto err_clk; } /* cpu init code should really have flagged this device as * being wake-capable; if it didn't, do that here. */ if (!device_can_wakeup(&pdev->dev)) device_init_wakeup(&pdev->dev, 1); 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 = devm_rtc_register_device(rtc); if (ret) goto err_clk; /* enable SECEV interrupt in order to initialize at91_rtc_upd_rdy * completion. */ at91_rtc_write_ier(AT91_RTC_SECEV); dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n"); return 0; err_clk: clk_disable_unprepare(sclk); return ret; } /* * Disable and remove the RTC driver */ static void __exit at91_rtc_remove(struct platform_device *pdev) { /* Disable all interrupts */ at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV); clk_disable_unprepare(sclk); } static void at91_rtc_shutdown(struct platform_device *pdev) { /* Disable all interrupts */ at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM | AT91_RTC_SECEV | AT91_RTC_TIMEV | AT91_RTC_CALEV); } #ifdef CONFIG_PM_SLEEP /* AT91RM9200 RTC Power management control */ static int at91_rtc_suspend(struct device *dev) { /* this IRQ is shared with DBGU and other hardware which isn't * necessarily doing PM like we are... */ at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM); at91_rtc_imr = at91_rtc_read_imr() & (AT91_RTC_ALARM|AT91_RTC_SECEV); if (at91_rtc_imr) { if (device_may_wakeup(dev)) { unsigned long flags; enable_irq_wake(irq); spin_lock_irqsave(&suspended_lock, flags); suspended = true; spin_unlock_irqrestore(&suspended_lock, flags); } else { at91_rtc_write_idr(at91_rtc_imr); } } return 0; } static int at91_rtc_resume(struct device *dev) { struct rtc_device *rtc = dev_get_drvdata(dev); if (at91_rtc_imr) { if (device_may_wakeup(dev)) { unsigned long flags; spin_lock_irqsave(&suspended_lock, flags); if (cached_events) { rtc_update_irq(rtc, 1, cached_events); cached_events = 0; } suspended = false; spin_unlock_irqrestore(&suspended_lock, flags); disable_irq_wake(irq); } at91_rtc_write_ier(at91_rtc_imr); } return 0; } #endif static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume); /* * at91_rtc_remove() lives in .exit.text. For drivers registered via * module_platform_driver_probe() this is ok because they cannot get unbound at * runtime. So mark the driver struct with __refdata to prevent modpost * triggering a section mismatch warning. */ static struct platform_driver at91_rtc_driver __refdata = { .remove = __exit_p(at91_rtc_remove), .shutdown = at91_rtc_shutdown, .driver = { .name = "at91_rtc", .pm = &at91_rtc_pm_ops, .of_match_table = at91_rtc_dt_ids, }, }; module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe); MODULE_AUTHOR("Rick Bronson"); MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:at91_rtc");