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linux/drivers/rtc/rtc-at91rm9200.c
David Brownell 7ca1d488ff rtc: suspend()/resume() restores system clock 
RTC class suspend/resume support, re-initializing the system clock on resume
from the clock used to initialize it at boot time.

 - The reinit-on-resume is hooked to the existing RTC_HCTOSYS config
   option, on the grounds that a clock good enough for init must also
   be good enough for re-init.

 - Inlining a version of the code used by ARM, to save and restore the
   delta between a selected RTC and the current system wall-clock time.

 - Removes calls to that ARM code from AT91, OMAP1, and S3C RTCs.  This
   means that systems using those RTCs across suspend/resume will likely
   want to change their kernel configs to enable RTC_HCTOSYS.

   If HCTOSYS isn't using a second RTC (with battery?), this changes the
   system's initial date from Jan 1970 to the epoch this hardware uses:
   1998 for AT91, 2000 for OMAP1 (assuming no split power mode), etc.

This goes on top of the patch series removing "struct class_device" usage
from the RTC framework.  That's all needed for class suspend()/resume().

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-By: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:18 -07:00

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/*
* 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/ioctl.h>
#include <linux/completion.h>
#include <asm/uaccess.h>
#include <asm/rtc.h>
#include <asm/mach/time.h>
#include <asm/arch/at91_rtc.h>
#define AT91_RTC_FREQ 1
#define AT91_RTC_EPOCH 1900UL /* just like arch/arm/common/rtctime.c */
static DECLARE_COMPLETION(at91_rtc_updated);
static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
/*
* 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_sys_read(timereg);
date = at91_sys_read(calreg);
} while ((time != at91_sys_read(timereg)) ||
(date != at91_sys_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 wille 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;
pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
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;
pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
/* Stop Time/Calendar from counting */
cr = at91_sys_read(AT91_RTC_CR);
at91_sys_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
at91_sys_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
at91_sys_write(AT91_RTC_TIMR,
BIN2BCD(tm->tm_sec) << 0
| BIN2BCD(tm->tm_min) << 8
| BIN2BCD(tm->tm_hour) << 16);
at91_sys_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_sys_read(AT91_RTC_CR);
at91_sys_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
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_sys_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
? 1 : 0;
pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
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_hour = alrm->time.tm_hour;
tm.tm_min = alrm->time.tm_min;
tm.tm_sec = alrm->time.tm_sec;
at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
at91_sys_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_sys_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_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __FUNCTION__,
at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
tm.tm_min, tm.tm_sec);
return 0;
}
/*
* Handle commands from user-space
*/
static int at91_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
int ret = 0;
pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __FUNCTION__, cmd, arg);
switch (cmd) {
case RTC_AIE_OFF: /* alarm off */
at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM);
break;
case RTC_AIE_ON: /* alarm on */
at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM);
break;
case RTC_UIE_OFF: /* update off */
case RTC_PIE_OFF: /* periodic off */
at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV);
break;
case RTC_UIE_ON: /* update on */
case RTC_PIE_ON: /* periodic on */
at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV);
break;
case RTC_IRQP_READ: /* read periodic alarm frequency */
ret = put_user(AT91_RTC_FREQ, (unsigned long *) arg);
break;
case RTC_IRQP_SET: /* set periodic alarm frequency */
if (arg != AT91_RTC_FREQ)
ret = -EINVAL;
break;
default:
ret = -ENOIOCTLCMD;
break;
}
return ret;
}
/*
* Provide additional RTC information in /proc/driver/rtc
*/
static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
{
unsigned long imr = at91_sys_read(AT91_RTC_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");
seq_printf(seq, "periodic_freq\t: %ld\n",
(unsigned long) AT91_RTC_FREQ);
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;
rtsr = at91_sys_read(AT91_RTC_SR) & at91_sys_read(AT91_RTC_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)
events |= (RTC_UF | RTC_IRQF);
if (rtsr & AT91_RTC_ACKUPD)
complete(&at91_rtc_updated);
at91_sys_write(AT91_RTC_SCCR, rtsr); /* clear status reg */
rtc_update_irq(rtc, 1, events);
pr_debug("%s(): num=%ld, events=0x%02lx\n", __FUNCTION__,
events >> 8, events & 0x000000FF);
return IRQ_HANDLED;
}
return IRQ_NONE; /* not handled */
}
static const struct rtc_class_ops at91_rtc_ops = {
.ioctl = at91_rtc_ioctl,
.read_time = at91_rtc_readtime,
.set_time = at91_rtc_settime,
.read_alarm = at91_rtc_readalarm,
.set_alarm = at91_rtc_setalarm,
.proc = at91_rtc_proc,
};
/*
* Initialize and install RTC driver
*/
static int __init at91_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
int ret;
at91_sys_write(AT91_RTC_CR, 0);
at91_sys_write(AT91_RTC_MR, 0); /* 24 hour mode */
/* Disable all interrupts */
at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
AT91_RTC_SECEV | AT91_RTC_TIMEV |
AT91_RTC_CALEV);
ret = request_irq(AT91_ID_SYS, at91_rtc_interrupt,
IRQF_DISABLED | IRQF_SHARED,
"at91_rtc", pdev);
if (ret) {
printk(KERN_ERR "at91_rtc: IRQ %d already in use.\n",
AT91_ID_SYS);
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 = rtc_device_register(pdev->name, &pdev->dev,
&at91_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
free_irq(AT91_ID_SYS, pdev);
return PTR_ERR(rtc);
}
platform_set_drvdata(pdev, rtc);
printk(KERN_INFO "AT91 Real Time Clock driver.\n");
return 0;
}
/*
* Disable and remove the RTC driver
*/
static int __exit at91_rtc_remove(struct platform_device *pdev)
{
struct rtc_device *rtc = platform_get_drvdata(pdev);
/* Disable all interrupts */
at91_sys_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
AT91_RTC_SECEV | AT91_RTC_TIMEV |
AT91_RTC_CALEV);
free_irq(AT91_ID_SYS, pdev);
rtc_device_unregister(rtc);
platform_set_drvdata(pdev, NULL);
return 0;
}
#ifdef CONFIG_PM
/* AT91RM9200 RTC Power management control */
static u32 at91_rtc_imr;
static int at91_rtc_suspend(struct platform_device *pdev, pm_message_t state)
{
/* this IRQ is shared with DBGU and other hardware which isn't
* necessarily doing PM like we are...
*/
at91_rtc_imr = at91_sys_read(AT91_RTC_IMR)
& (AT91_RTC_ALARM|AT91_RTC_SECEV);
if (at91_rtc_imr) {
if (device_may_wakeup(&pdev->dev))
enable_irq_wake(AT91_ID_SYS);
else
at91_sys_write(AT91_RTC_IDR, at91_rtc_imr);
}
return 0;
}
static int at91_rtc_resume(struct platform_device *pdev)
{
if (at91_rtc_imr) {
if (device_may_wakeup(&pdev->dev))
disable_irq_wake(AT91_ID_SYS);
else
at91_sys_write(AT91_RTC_IER, at91_rtc_imr);
}
return 0;
}
#else
#define at91_rtc_suspend NULL
#define at91_rtc_resume NULL
#endif
static struct platform_driver at91_rtc_driver = {
.remove = __exit_p(at91_rtc_remove),
.suspend = at91_rtc_suspend,
.resume = at91_rtc_resume,
.driver = {
.name = "at91_rtc",
.owner = THIS_MODULE,
},
};
static int __init at91_rtc_init(void)
{
return platform_driver_probe(&at91_rtc_driver, at91_rtc_probe);
}
static void __exit at91_rtc_exit(void)
{
platform_driver_unregister(&at91_rtc_driver);
}
module_init(at91_rtc_init);
module_exit(at91_rtc_exit);
MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
MODULE_LICENSE("GPL");
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