/* * Real Time Clock interface for StrongARM SA1x00 and XScale PXA2xx * * Copyright (c) 2000 Nils Faerber * * Based on rtc.c by Paul Gortmaker * * Original Driver by Nils Faerber * * Modifications from: * CIH * Nicolas Pitre * Andrew Christian * * Converted to the RTC subsystem and Driver Model * by Richard Purdie * * 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. */ #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_ARCH_PXA #include #include #endif #define RTC_DEF_DIVIDER (32768 - 1) #define RTC_DEF_TRIM 0 static const unsigned long RTC_FREQ = 1024; static unsigned long timer_freq; static struct rtc_time rtc_alarm; static DEFINE_SPINLOCK(sa1100_rtc_lock); static inline int rtc_periodic_alarm(struct rtc_time *tm) { return (tm->tm_year == -1) || ((unsigned)tm->tm_mon >= 12) || ((unsigned)(tm->tm_mday - 1) >= 31) || ((unsigned)tm->tm_hour > 23) || ((unsigned)tm->tm_min > 59) || ((unsigned)tm->tm_sec > 59); } /* * Calculate the next alarm time given the requested alarm time mask * and the current time. */ static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm) { unsigned long next_time; unsigned long now_time; next->tm_year = now->tm_year; next->tm_mon = now->tm_mon; next->tm_mday = now->tm_mday; next->tm_hour = alrm->tm_hour; next->tm_min = alrm->tm_min; next->tm_sec = alrm->tm_sec; rtc_tm_to_time(now, &now_time); rtc_tm_to_time(next, &next_time); if (next_time < now_time) { /* Advance one day */ next_time += 60 * 60 * 24; rtc_time_to_tm(next_time, next); } } static int rtc_update_alarm(struct rtc_time *alrm) { struct rtc_time alarm_tm, now_tm; unsigned long now, time; int ret; do { now = RCNR; rtc_time_to_tm(now, &now_tm); rtc_next_alarm_time(&alarm_tm, &now_tm, alrm); ret = rtc_tm_to_time(&alarm_tm, &time); if (ret != 0) break; RTSR = RTSR & (RTSR_HZE|RTSR_ALE|RTSR_AL); RTAR = time; } while (now != RCNR); return ret; } static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) { struct platform_device *pdev = to_platform_device(dev_id); struct rtc_device *rtc = platform_get_drvdata(pdev); unsigned int rtsr; unsigned long events = 0; spin_lock(&sa1100_rtc_lock); rtsr = RTSR; /* clear interrupt sources */ RTSR = 0; /* Fix for a nasty initialization problem the in SA11xx RTSR register. * See also the comments in sa1100_rtc_probe(). */ if (rtsr & (RTSR_ALE | RTSR_HZE)) { /* This is the original code, before there was the if test * above. This code does not clear interrupts that were not * enabled. */ RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); } else { /* For some reason, it is possible to enter this routine * without interruptions enabled, it has been tested with * several units (Bug in SA11xx chip?). * * This situation leads to an infinite "loop" of interrupt * routine calling and as a result the processor seems to * lock on its first call to open(). */ RTSR = RTSR_AL | RTSR_HZ; } /* clear alarm interrupt if it has occurred */ if (rtsr & RTSR_AL) rtsr &= ~RTSR_ALE; RTSR = rtsr & (RTSR_ALE | RTSR_HZE); /* update irq data & counter */ if (rtsr & RTSR_AL) events |= RTC_AF | RTC_IRQF; if (rtsr & RTSR_HZ) events |= RTC_UF | RTC_IRQF; rtc_update_irq(rtc, 1, events); if (rtsr & RTSR_AL && rtc_periodic_alarm(&rtc_alarm)) rtc_update_alarm(&rtc_alarm); spin_unlock(&sa1100_rtc_lock); return IRQ_HANDLED; } static int sa1100_irq_set_freq(struct device *dev, int freq) { if (freq < 1 || freq > timer_freq) { return -EINVAL; } else { struct rtc_device *rtc = (struct rtc_device *)dev; rtc->irq_freq = freq; return 0; } } static int rtc_timer1_count; static int sa1100_irq_set_state(struct device *dev, int enabled) { spin_lock_irq(&sa1100_rtc_lock); if (enabled) { struct rtc_device *rtc = (struct rtc_device *)dev; OSMR1 = timer_freq / rtc->irq_freq + OSCR; OIER |= OIER_E1; rtc_timer1_count = 1; } else { OIER &= ~OIER_E1; } spin_unlock_irq(&sa1100_rtc_lock); return 0; } static inline int sa1100_timer1_retrigger(struct rtc_device *rtc) { unsigned long diff; unsigned long period = timer_freq / rtc->irq_freq; spin_lock_irq(&sa1100_rtc_lock); do { OSMR1 += period; diff = OSMR1 - OSCR; /* If OSCR > OSMR1, diff is a very large number (unsigned * math). This means we have a lost interrupt. */ } while (diff > period); OIER |= OIER_E1; spin_unlock_irq(&sa1100_rtc_lock); return 0; } static irqreturn_t timer1_interrupt(int irq, void *dev_id) { struct platform_device *pdev = to_platform_device(dev_id); struct rtc_device *rtc = platform_get_drvdata(pdev); /* * If we match for the first time, rtc_timer1_count will be 1. * Otherwise, we wrapped around (very unlikely but * still possible) so compute the amount of missed periods. * The match reg is updated only when the data is actually retrieved * to avoid unnecessary interrupts. */ OSSR = OSSR_M1; /* clear match on timer1 */ rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF); if (rtc_timer1_count == 1) rtc_timer1_count = (rtc->irq_freq * ((1 << 30) / (timer_freq >> 2))); /* retrigger. */ sa1100_timer1_retrigger(rtc); return IRQ_HANDLED; } static int sa1100_rtc_read_callback(struct device *dev, int data) { if (data & RTC_PF) { struct rtc_device *rtc = (struct rtc_device *)dev; /* interpolate missed periods and set match for the next */ unsigned long period = timer_freq / rtc->irq_freq; unsigned long oscr = OSCR; unsigned long osmr1 = OSMR1; unsigned long missed = (oscr - osmr1)/period; data += missed << 8; OSSR = OSSR_M1; /* clear match on timer 1 */ OSMR1 = osmr1 + (missed + 1)*period; /* Ensure we didn't miss another match in the mean time. * Here we compare (match - OSCR) 8 instead of 0 -- * see comment in pxa_timer_interrupt() for explanation. */ while ((signed long)((osmr1 = OSMR1) - OSCR) <= 8) { data += 0x100; OSSR = OSSR_M1; /* clear match on timer 1 */ OSMR1 = osmr1 + period; } } return data; } static int sa1100_rtc_open(struct device *dev) { int ret; struct rtc_device *rtc = (struct rtc_device *)dev; ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED, "rtc 1Hz", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz); goto fail_ui; } ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED, "rtc Alrm", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm); goto fail_ai; } ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED, "rtc timer", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1); goto fail_pi; } rtc->max_user_freq = RTC_FREQ; sa1100_irq_set_freq(dev, RTC_FREQ); return 0; fail_pi: free_irq(IRQ_RTCAlrm, dev); fail_ai: free_irq(IRQ_RTC1Hz, dev); fail_ui: return ret; } static void sa1100_rtc_release(struct device *dev) { spin_lock_irq(&sa1100_rtc_lock); RTSR = 0; OIER &= ~OIER_E1; OSSR = OSSR_M1; spin_unlock_irq(&sa1100_rtc_lock); free_irq(IRQ_OST1, dev); free_irq(IRQ_RTCAlrm, dev); free_irq(IRQ_RTC1Hz, dev); } static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { switch (cmd) { case RTC_UIE_OFF: spin_lock_irq(&sa1100_rtc_lock); RTSR &= ~RTSR_HZE; spin_unlock_irq(&sa1100_rtc_lock); return 0; case RTC_UIE_ON: spin_lock_irq(&sa1100_rtc_lock); RTSR |= RTSR_HZE; spin_unlock_irq(&sa1100_rtc_lock); return 0; } return -ENOIOCTLCMD; } static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { spin_lock_irq(&sa1100_rtc_lock); if (enabled) RTSR |= RTSR_ALE; else RTSR &= ~RTSR_ALE; spin_unlock_irq(&sa1100_rtc_lock); return 0; } static int sa1100_rtc_read_time(struct device *dev, struct rtc_time *tm) { rtc_time_to_tm(RCNR, tm); return 0; } static int sa1100_rtc_set_time(struct device *dev, struct rtc_time *tm) { unsigned long time; int ret; ret = rtc_tm_to_time(tm, &time); if (ret == 0) RCNR = time; return ret; } static int sa1100_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { u32 rtsr; memcpy(&alrm->time, &rtc_alarm, sizeof(struct rtc_time)); rtsr = RTSR; alrm->enabled = (rtsr & RTSR_ALE) ? 1 : 0; alrm->pending = (rtsr & RTSR_AL) ? 1 : 0; return 0; } static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { int ret; spin_lock_irq(&sa1100_rtc_lock); ret = rtc_update_alarm(&alrm->time); if (ret == 0) { if (alrm->enabled) RTSR |= RTSR_ALE; else RTSR &= ~RTSR_ALE; } spin_unlock_irq(&sa1100_rtc_lock); return ret; } static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) { struct rtc_device *rtc = (struct rtc_device *)dev; seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR); seq_printf(seq, "update_IRQ\t: %s\n", (RTSR & RTSR_HZE) ? "yes" : "no"); seq_printf(seq, "periodic_IRQ\t: %s\n", (OIER & OIER_E1) ? "yes" : "no"); seq_printf(seq, "periodic_freq\t: %d\n", rtc->irq_freq); seq_printf(seq, "RTSR\t\t: 0x%08x\n", (u32)RTSR); return 0; } static const struct rtc_class_ops sa1100_rtc_ops = { .open = sa1100_rtc_open, .read_callback = sa1100_rtc_read_callback, .release = sa1100_rtc_release, .ioctl = sa1100_rtc_ioctl, .read_time = sa1100_rtc_read_time, .set_time = sa1100_rtc_set_time, .read_alarm = sa1100_rtc_read_alarm, .set_alarm = sa1100_rtc_set_alarm, .proc = sa1100_rtc_proc, .irq_set_freq = sa1100_irq_set_freq, .irq_set_state = sa1100_irq_set_state, .alarm_irq_enable = sa1100_rtc_alarm_irq_enable, }; static int sa1100_rtc_probe(struct platform_device *pdev) { struct rtc_device *rtc; timer_freq = get_clock_tick_rate(); /* * According to the manual we should be able to let RTTR be zero * and then a default diviser for a 32.768KHz clock is used. * Apparently this doesn't work, at least for my SA1110 rev 5. * If the clock divider is uninitialized then reset it to the * default value to get the 1Hz clock. */ if (RTTR == 0) { RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); dev_warn(&pdev->dev, "warning: " "initializing default clock divider/trim value\n"); /* The current RTC value probably doesn't make sense either */ RCNR = 0; } device_init_wakeup(&pdev->dev, 1); rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(pdev, rtc); /* Set the irq_freq */ /*TODO: Find out who is messing with this value after we initialize * it here.*/ rtc->irq_freq = RTC_FREQ; /* Fix for a nasty initialization problem the in SA11xx RTSR register. * See also the comments in sa1100_rtc_interrupt(). * * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an * interrupt pending, even though interrupts were never enabled. * In this case, this bit it must be reset before enabling * interruptions to avoid a nonexistent interrupt to occur. * * In principle, the same problem would apply to bit 0, although it has * never been observed to happen. * * This issue is addressed both here and in sa1100_rtc_interrupt(). * If the issue is not addressed here, in the times when the processor * wakes up with the bit set there will be one spurious interrupt. * * The issue is also dealt with in sa1100_rtc_interrupt() to be on the * safe side, once the condition that lead to this strange * initialization is unknown and could in principle happen during * normal processing. * * Notice that clearing bit 1 and 0 is accomplished by writting ONES to * the corresponding bits in RTSR. */ RTSR = RTSR_AL | RTSR_HZ; return 0; } static int sa1100_rtc_remove(struct platform_device *pdev) { struct rtc_device *rtc = platform_get_drvdata(pdev); if (rtc) rtc_device_unregister(rtc); return 0; } #ifdef CONFIG_PM static int sa1100_rtc_suspend(struct device *dev) { if (device_may_wakeup(dev)) enable_irq_wake(IRQ_RTCAlrm); return 0; } static int sa1100_rtc_resume(struct device *dev) { if (device_may_wakeup(dev)) disable_irq_wake(IRQ_RTCAlrm); return 0; } static const struct dev_pm_ops sa1100_rtc_pm_ops = { .suspend = sa1100_rtc_suspend, .resume = sa1100_rtc_resume, }; #endif static struct platform_driver sa1100_rtc_driver = { .probe = sa1100_rtc_probe, .remove = sa1100_rtc_remove, .driver = { .name = "sa1100-rtc", #ifdef CONFIG_PM .pm = &sa1100_rtc_pm_ops, #endif }, }; static int __init sa1100_rtc_init(void) { return platform_driver_register(&sa1100_rtc_driver); } static void __exit sa1100_rtc_exit(void) { platform_driver_unregister(&sa1100_rtc_driver); } module_init(sa1100_rtc_init); module_exit(sa1100_rtc_exit); MODULE_AUTHOR("Richard Purdie "); MODULE_DESCRIPTION("SA11x0/PXA2xx Realtime Clock Driver (RTC)"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:sa1100-rtc");