--- /dev/null
+/*
+ * 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
+ *
+ * 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 <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/time.h>
+#include <linux/rtc.h>
+#include <linux/bcd.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <linux/ioctl.h>
+#include <linux/completion.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/suspend.h>
+#include <linux/uaccess.h>
+
+#include "rtc-at91rm9200.h"
+
+#define at91_rtc_read(field) \
+ readl_relaxed(at91_rtc_regs + field)
+#define at91_rtc_write(field, val) \
+ writel_relaxed((val), at91_rtc_regs + field)
+
+#define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
+
+struct at91_rtc_config {
+ bool use_shadow_imr;
+};
+
+static const struct at91_rtc_config *at91_rtc_config;
+static DECLARE_COMPLETION(at91_rtc_updated);
+static DECLARE_COMPLETION(at91_rtc_upd_rdy);
+static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
+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 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 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((time & AT91_RTC_SEC) >> 0);
+ tm->tm_min = bcd2bin((time & AT91_RTC_MIN) >> 8);
+ tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
+
+ /*
+ * The Calendar Alarm register does not have a field for
+ * the year - so these will return an invalid value. When an
+ * alarm is set, at91_alarm_year will store the current year.
+ */
+ tm->tm_year = bcd2bin(date & AT91_RTC_CENT) * 100; /* century */
+ tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8); /* year */
+
+ tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
+ tm->tm_mon = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
+ tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
+}
+
+/*
+ * 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(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
+ 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+ 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(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
+ 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+ 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,
+ bin2bcd(tm->tm_sec) << 0
+ | bin2bcd(tm->tm_min) << 8
+ | bin2bcd(tm->tm_hour) << 16);
+
+ at91_rtc_write(AT91_RTC_CALR,
+ bin2bcd((tm->tm_year + 1900) / 100) /* century */
+ | bin2bcd(tm->tm_year % 100) << 8 /* year */
+ | bin2bcd(tm->tm_mon + 1) << 16 /* tm_mon starts at zero */
+ | bin2bcd(tm->tm_wday + 1) << 21 /* day of the week [0-6], Sunday=0 */
+ | bin2bcd(tm->tm_mday) << 24);
+
+ /* 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_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
+ tm->tm_year = at91_alarm_year - 1900;
+
+ alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
+ ? 1 : 0;
+
+ dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
+ 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+ 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;
+
+ at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
+
+ at91_alarm_year = tm.tm_year;
+
+ tm.tm_mon = alrm->time.tm_mon;
+ tm.tm_mday = alrm->time.tm_mday;
+ tm.tm_hour = alrm->time.tm_hour;
+ tm.tm_min = alrm->time.tm_min;
+ tm.tm_sec = alrm->time.tm_sec;
+
+ at91_rtc_write_idr(AT91_RTC_ALARM);
+ at91_rtc_write(AT91_RTC_TIMALR,
+ bin2bcd(tm.tm_sec) << 0
+ | bin2bcd(tm.tm_min) << 8
+ | bin2bcd(tm.tm_hour) << 16
+ | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
+ at91_rtc_write(AT91_RTC_CALALR,
+ bin2bcd(tm.tm_mon + 1) << 16 /* tm_mon starts at zero */
+ | bin2bcd(tm.tm_mday) << 24
+ | 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(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
+ at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
+ tm.tm_min, tm.tm_sec);
+
+ 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;
+}
+/*
+ * Provide additional RTC information in /proc/driver/rtc
+ */
+static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+ unsigned long imr = at91_rtc_read_imr();
+
+ seq_printf(seq, "update_IRQ\t: %s\n",
+ (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
+ seq_printf(seq, "periodic_IRQ\t: %s\n",
+ (imr & AT91_RTC_SECEV) ? "yes" : "no");
+
+ 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,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id at91_rtc_dt_ids[] = {
+ {
+ .compatible = "atmel,at91rm9200-rtc",
+ .data = &at91rm9200_config,
+ }, {
+ .compatible = "atmel,at91sam9x5-rtc",
+ .data = &at91sam9x5_config,
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
+#endif
+
+static const struct at91_rtc_config *
+at91_rtc_get_config(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+
+ if (pdev->dev.of_node) {
+ match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
+ if (!match)
+ return NULL;
+ return (const struct at91_rtc_config *)match->data;
+ }
+
+ return &at91rm9200_config;
+}
+
+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,
+ .proc = at91_rtc_proc,
+ .alarm_irq_enable = at91_rtc_alarm_irq_enable,
+};
+
+/*
+ * 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 = at91_rtc_get_config(pdev);
+ 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) {
+ dev_err(&pdev->dev, "no irq resource defined\n");
+ 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;
+ }
+
+ at91_rtc_write(AT91_RTC_CR, 0);
+ at91_rtc_write(AT91_RTC_MR, 0); /* 24 hour mode */
+
+ /* 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);
+ return ret;
+ }
+
+ /* 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);
+
+ rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
+ &at91_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+ platform_set_drvdata(pdev, rtc);
+
+ /* 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;
+}
+
+/*
+ * Disable and remove the RTC driver
+ */
+static int __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);
+
+ return 0;
+}
+
+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_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);
+
+static struct platform_driver at91_rtc_driver = {
+ .remove = __exit_p(at91_rtc_remove),
+ .shutdown = at91_rtc_shutdown,
+ .driver = {
+ .name = "at91_rtc",
+ .pm = &at91_rtc_pm_ops,
+ .of_match_table = of_match_ptr(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");
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