diff options
Diffstat (limited to 'drivers/rtc/rtc-sa1100.c')
-rw-r--r-- | drivers/rtc/rtc-sa1100.c | 187 |
1 files changed, 66 insertions, 121 deletions
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c index e4a44b64170..0b40bb88a88 100644 --- a/drivers/rtc/rtc-sa1100.c +++ b/drivers/rtc/rtc-sa1100.c @@ -39,11 +39,10 @@ #include <mach/regs-ost.h> #endif -#define RTC_DEF_DIVIDER 32768 - 1 +#define RTC_DEF_DIVIDER (32768 - 1) #define RTC_DEF_TRIM 0 -static unsigned long rtc_freq = 1024; -static unsigned long timer_freq; +static const unsigned long RTC_FREQ = 1024; static struct rtc_time rtc_alarm; static DEFINE_SPINLOCK(sa1100_rtc_lock); @@ -61,7 +60,8 @@ static inline int rtc_periodic_alarm(struct rtc_time *tm) * 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) +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; @@ -116,7 +116,23 @@ static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) rtsr = RTSR; /* clear interrupt sources */ RTSR = 0; - RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); + /* 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) @@ -139,80 +155,29 @@ static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } -static int rtc_timer1_count; - -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_freq * ((1 << 30) / (timer_freq >> 2))); - - return IRQ_HANDLED; -} - -static int sa1100_rtc_read_callback(struct device *dev, int data) -{ - if (data & RTC_PF) { - /* interpolate missed periods and set match for the next */ - unsigned long period = timer_freq / rtc_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 platform_device *plat_dev = to_platform_device(dev); + struct rtc_device *rtc = platform_get_drvdata(plat_dev); ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED, - "rtc 1Hz", dev); + "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); + "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; + rtc_irq_set_freq(rtc, NULL, RTC_FREQ); + return 0; - fail_pi: - free_irq(IRQ_RTCAlrm, dev); fail_ai: free_irq(IRQ_RTC1Hz, dev); fail_ui: @@ -227,57 +192,19 @@ static void sa1100_rtc_release(struct device *dev) 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) +static int sa1100_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { - switch(cmd) { - case RTC_AIE_OFF: - spin_lock_irq(&sa1100_rtc_lock); - RTSR &= ~RTSR_ALE; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - case RTC_AIE_ON: - spin_lock_irq(&sa1100_rtc_lock); + spin_lock_irq(&sa1100_rtc_lock); + if (enabled) RTSR |= RTSR_ALE; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - 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; - case RTC_PIE_OFF: - spin_lock_irq(&sa1100_rtc_lock); - OIER &= ~OIER_E1; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - case RTC_PIE_ON: - spin_lock_irq(&sa1100_rtc_lock); - OSMR1 = timer_freq / rtc_freq + OSCR; - OIER |= OIER_E1; - rtc_timer1_count = 1; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - case RTC_IRQP_READ: - return put_user(rtc_freq, (unsigned long *)arg); - case RTC_IRQP_SET: - if (arg < 1 || arg > timer_freq) - return -EINVAL; - rtc_freq = arg; - return 0; - } - return -ENOIOCTLCMD; + 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) @@ -327,34 +254,27 @@ static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) { - 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: %ld\n", rtc_freq); + seq_printf(seq, "trim/divider\t\t: 0x%08x\n", (u32) RTTR); + seq_printf(seq, "RTSR\t\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, + .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. @@ -364,7 +284,8 @@ static int sa1100_rtc_probe(struct platform_device *pdev) */ if (RTTR == 0) { RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); - dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n"); + dev_warn(&pdev->dev, "warning: " + "initializing default clock divider/trim value\n"); /* The current RTC value probably doesn't make sense either */ RCNR = 0; } @@ -372,13 +293,37 @@ static int sa1100_rtc_probe(struct platform_device *pdev) device_init_wakeup(&pdev->dev, 1); rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, - THIS_MODULE); + THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(pdev, rtc); + /* 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; } @@ -386,7 +331,7 @@ static int sa1100_rtc_remove(struct platform_device *pdev) { struct rtc_device *rtc = platform_get_drvdata(pdev); - if (rtc) + if (rtc) rtc_device_unregister(rtc); return 0; |