/*
* RTC class driver for "CMOS RTC": PCs, ACPI, etc
*
* Copyright (C) 1996 Paul Gortmaker (drivers/char/rtc.c)
* Copyright (C) 2006 David Brownell (convert to new framework)
*
* 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.
*/
/*
* The original "cmos clock" chip was an MC146818 chip, now obsolete.
* That defined the register interface now provided by all PCs, some
* non-PC systems, and incorporated into ACPI. Modern PC chipsets
* integrate an MC146818 clone in their southbridge, and boards use
* that instead of discrete clones like the DS12887 or M48T86. There
* are also clones that connect using the LPC bus.
*
* That register API is also used directly by various other drivers
* (notably for integrated NVRAM), infrastructure (x86 has code to
* bypass the RTC framework, directly reading the RTC during boot
* and updating minutes/seconds for systems using NTP synch) and
* utilities (like userspace 'hwclock', if no /dev node exists).
*
* So **ALL** calls to CMOS_READ and CMOS_WRITE must be done with
* interrupts disabled, holding the global rtc_lock, to exclude those
* other drivers and utilities on correctly configured systems.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
/* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
#include <asm-generic/rtc.h>
struct cmos_rtc {
struct rtc_device *rtc;
struct device *dev;
int irq;
struct resource *iomem;
u8 suspend_ctrl;
/* newer hardware extends the original register set */
u8 day_alrm;
u8 mon_alrm;
u8 century;
};
/* both platform and pnp busses use negative numbers for invalid irqs */
#define is_valid_irq(n) ((n) >= 0)
static const char driver_name[] = "rtc_cmos";
/*----------------------------------------------------------------*/
static int cmos_read_time(struct device *dev, struct rtc_time *t)
{
/* REVISIT: if the clock has a "century" register, use
* that instead of the heuristic in get_rtc_time().
* That'll make Y3K compatility (year > 2070) easy!
*/
get_rtc_time(t);
return 0;
}
static int cmos_set_time(struct device *dev, struct rtc_time *t)
{
/* REVISIT: set the "century" register if available
*
* NOTE: this ignores the issue whereby updating the seconds
* takes effect exactly 500ms after we write the register.
* (Also queueing and other delays before we get this far.)
*/
return set_rtc_time(t);
}
static int cmos_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char rtc_control;
if (!is_valid_irq(cmos->irq))
return -EIO;
/* Basic alarms only support hour, minute, and seconds fields.
* Some also support day and month, for alarms up to a year in
* the future.
*/
t->time.tm_mday = -1;
t->time.tm_mon = -1;
spin_lock_irq(&rtc_lock);
t->time.tm_sec = CMOS_READ(RTC_SECONDS_ALARM);
t->time.tm_min = CMOS_READ(RTC_MINUTES_ALARM);
t->time.tm_hour = CMOS_READ(RTC_HOURS_ALARM);
if (cmos->day_alrm) {
t->time.tm_mday = CMOS_READ(cmos->day_alrm);
if (!t->time.tm_mday)
t->time.tm_mday = -1;
if (cmos->mon_alrm) {
t->time.tm_mon = CMOS_READ(cmos->mon_alrm);
if (!t->time.tm_mon)
t->time.tm_mon = -1;
}
}
rtc_control = CMOS_READ(RTC_CONTROL);
spin_unlock_irq(&rtc_lock);
/* REVISIT this assumes PC style usage: always BCD */
if (((unsigned)t->time.tm_sec) < 0x60)
t->time.tm_sec = BCD2BIN(t->time.tm_sec);
else
t->time.tm_sec = -1;
if (((unsigned)t->time.tm_min) < 0x60)
t->time.tm_min = BCD2BIN(t->time.tm_min);
else
t->time.tm_min = -1;
if (((unsigned)t->time.tm_hour) < 0x24)
t->time.tm_hour = BCD2BIN(t->time.tm_hour);
else
t->time.tm_hour = -1;
if (cmos->day_alrm) {
if (((unsigned)t->time.tm_mday) <= 0x31)
t->time.tm_mday = BCD2BIN(t->time.tm_mday);
else
t->time.tm_mday = -1;
if (cmos->mon_alrm) {
if (((unsigned)t->time.tm_mon) <= 0x12)
t->time.tm_mon = BCD2BIN(t->time.tm_mon) - 1;
else
t->time.tm_mon = -1;
}
}
t->time.tm_year = -1;
t->enabled = !!(rtc_control & RTC_AIE);
t->pending = 0;
return 0;
}
static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char mon, mday, hrs, min, sec;
unsigned char rtc_control, rtc_intr;
if (!is_valid_irq(cmos->irq))
return -EIO;
/* REVISIT this assumes PC style usage: always BCD */
/* Writing 0xff means "don't care" or "match all". */
mon = t->time.tm_mon;
mon = (mon < 12) ? BIN2BCD(mon) : 0xff;
mon++;
mday = t->time.tm_mday;
mday = (mday >= 1 && mday <= 31) ? BIN2BCD(mday) : 0xff;
hrs = t->time.tm_hour;
hrs = (hrs < 24) ? BIN2BCD(hrs) : 0xff;
min = t->time.tm_min;
min = (min < 60) ? BIN2BCD(min) : 0xff;
sec = t->time.tm_sec;
sec = (sec < 60) ? BIN2BCD(sec) : 0xff;
spin_lock_irq(&rtc_lock);
/* next rtc irq must not be from previous alarm setting */
rtc_control = CMOS_READ(RTC_CONTROL);
rtc_control &= ~RTC_AIE;
CMOS_WRITE(rtc_control, RTC_CONTROL);
rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
if (rtc_intr)
rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
/* update alarm */
CMOS_WRITE(hrs, RTC_HOURS_ALARM);
CMOS_WRITE(min, RTC_MINUTES_ALARM);
CMOS_WRITE(sec, RTC_SECONDS_ALARM);
/* the system may support an "enhanced" alarm */
if (cmos->day_alrm) {
CMOS_WRITE(mday, cmos->day_alrm);
if (cmos->mon_alrm)
CMOS_WRITE(mon, cmos->mon_alrm);
}
if (t->enabled) {
rtc_control |= RTC_AIE;
CMOS_WRITE(rtc_control, RTC_CONTROL);
rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
if (rtc_intr)
rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
}
spin_unlock_irq(&rtc_lock);
return 0;
}
static int cmos_set_freq(struct device *dev, int freq)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
int f;
unsigned long flags;
if (!is_valid_irq(cmos->irq))
return -ENXIO;
/* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */
f = ffs(freq);
if (f != 0) {
if (f-- > 16 || freq != (1 << f))
return -EINVAL;
f = 16 - f;
}
spin_lock_irqsave(&rtc_lock, flags);
CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
#if defined(CONFIG_RTC_INTF_DEV) || defined(CONFIG_RTC_INTF_DEV_MODULE)
static int
cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char rtc_control, rtc_intr;
unsigned long flags;
switch (cmd) {
case RTC_AIE_OFF:
case RTC_AIE_ON:
case RTC_UIE_OFF:
case RTC_UIE_ON:
case RTC_PIE_OFF:
case RTC_PIE_ON:
if (!is_valid_irq(cmos->irq))
return -EINVAL;
break;
default:
return -ENOIOCTLCMD;
}
spin_lock_irqsave(&rtc_lock, flags);
rtc_control = CMOS_READ(RTC_CONTROL);
switch (cmd) {
case RTC_AIE_OFF: /* alarm off */
rtc_control &= ~RTC_AIE;
break;
case RTC_AIE_ON: /* alarm on */
rtc_control |= RTC_AIE;
break;
case RTC_UIE_OFF: /* update off */
rtc_control &= ~RTC_UIE;
break;
case RTC_UIE_ON: /* update on */
rtc_control |= RTC_UIE;
break;
case RTC_PIE_OFF: /* periodic off */
rtc_control &= ~RTC_PIE;
break;
case RTC_PIE_ON: /* periodic on */
rtc_control |= RTC_PIE;
break;
}
CMOS_WRITE(rtc_control, RTC_CONTROL);
rtc_intr = CMOS_READ(RTC_INTR_FLAGS);
if (rtc_intr)
rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
#else
#define cmos_rtc_ioctl NULL
#endif
#if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
static int cmos_procfs(struct device *dev, struct seq_file *seq)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char rtc_control, valid;
spin_lock_irq(&rtc_lock);
rtc_control = CMOS_READ(RTC_CONTROL);
valid = CMOS_READ(RTC_VALID);
spin_unlock_irq(&rtc_lock);
/* NOTE: at least ICH6 reports battery status using a different
* (non-RTC) bit; and SQWE is ignored on many current systems.
*/
return seq_printf(seq,
"periodic_IRQ\t: %s\n"
"update_IRQ\t: %s\n"
// "square_wave\t: %s\n"
// "BCD\t\t: %s\n"
"DST_enable\t: %s\n"
"periodic_freq\t: %d\n"
"batt_status\t: %s\n",
(rtc_control & RTC_PIE) ? "yes" : "no",
(rtc_control & RTC_UIE) ? "yes" : "no",
// (rtc_control & RTC_SQWE) ? "yes" : "no",
// (rtc_control & RTC_DM_BINARY) ? "no" : "yes",
(rtc_control & RTC_DST_EN) ? "yes" : "no",
cmos->rtc->irq_freq,
(valid & RTC_VRT) ? "okay" : "dead");
}
#else
#define cmos_procfs NULL
#endif
static const struct rtc_class_ops cmos_rtc_ops = {
.ioctl = cmos_rtc_ioctl,
.read_time = cmos_read_time,
.set_time = cmos_set_time,
.read_alarm = cmos_read_alarm,
.set_alarm = cmos_set_alarm,
.proc = cmos_procfs,
.irq_set_freq = cmos_set_freq,
};
/*----------------------------------------------------------------*/
static struct cmos_rtc cmos_rtc;
static irqreturn_t cmos_interrupt(int irq, void *p)
{
u8 irqstat;
spin_lock(&rtc_lock);
irqstat = CMOS_READ(RTC_INTR_FLAGS);
spin_unlock(&rtc_lock);
if (irqstat) {
/* NOTE: irqstat may have e.g. RTC_PF set
* even when RTC_PIE is clear...
*/
rtc_update_irq(p, 1, irqstat);
return IRQ_HANDLED;
} else
return IRQ_NONE;
}
#ifdef CONFIG_PNPACPI
#define is_pnpacpi() 1
#define INITSECTION
#else
#define is_pnpacpi() 0
#define INITSECTION __init
#endif
static int INITSECTION
cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
{
struct cmos_rtc_board_info *info = dev->platform_data;
int retval = 0;
unsigned char rtc_control;
/* there can be only one ... */
if (cmos_rtc.dev)
return -EBUSY;
if (!ports)
return -ENODEV;
cmos_rtc.irq = rtc_irq;
cmos_rtc.iomem = ports;
/* For ACPI systems the info comes from the FADT. On others,
* board specific setup provides it as appropriate.
*/
if (info) {
cmos_rtc.day_alrm = info->rtc_day_alarm;
cmos_rtc.mon_alrm = info->rtc_mon_alarm;
cmos_rtc.century = info->rtc_century;
}
cmos_rtc.rtc = rtc_device_register(driver_name, dev,
&cmos_rtc_ops, THIS_MODULE);
if (IS_ERR(cmos_rtc.rtc))
return PTR_ERR(cmos_rtc.rtc);
cmos_rtc.dev = dev;
dev_set_drvdata(dev, &cmos_rtc);
/* platform and pnp busses handle resources incompatibly.
*
* REVISIT for non-x86 systems we may need to handle io memory
* resources: ioremap them, and request_mem_region().
*/
if (is_pnpacpi()) {
retval = request_resource(&ioport_resource, ports);
if (retval < 0) {
dev_dbg(dev, "i/o registers already in use\n");
goto cleanup0;
}
}
rename_region(ports, cmos_rtc.rtc->class_dev.class_id);
spin_lock_irq(&rtc_lock);
/* force periodic irq to CMOS reset default of 1024Hz;
*
* REVISIT it's been reported that at least one x86_64 ALI mobo
* doesn't use 32KHz here ... for portability we might need to
* do something about other clock frequencies.
*/
CMOS_WRITE(RTC_REF_CLCK_32KHZ | 0x06, RTC_FREQ_SELECT);
cmos_rtc.rtc->irq_freq = 1024;
/* disable irqs.
*
* NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
* allegedly some older rtcs need that to handle irqs properly
*/
rtc_control = CMOS_READ(RTC_CONTROL);
rtc_control &= ~(RTC_PIE | RTC_AIE | RTC_UIE);
CMOS_WRITE(rtc_control, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
spin_unlock_irq(&rtc_lock);
/* FIXME teach the alarm code how to handle binary mode;
* <asm-generic/rtc.h> doesn't know 12-hour mode either.
*/
if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) {
dev_dbg(dev, "only 24-hr BCD mode supported\n");
retval = -ENXIO;
goto cleanup1;
}
if (is_valid_irq(rtc_irq))
retval = request_irq(rtc_irq, cmos_interrupt, IRQF_DISABLED,
cmos_rtc.rtc->class_dev.class_id,
&cmos_rtc.rtc->class_dev);
if (retval < 0) {
dev_dbg(dev, "IRQ %d is already in use\n", rtc_irq);
goto cleanup1;
}
/* REVISIT optionally make 50 or 114 bytes NVRAM available,
* like rtc-ds1553, rtc-ds1742 ... this will often include
* registers for century, and day/month alarm.
*/
pr_info("%s: alarms up to one %s%s\n",
cmos_rtc.rtc->class_dev.class_id,
is_valid_irq(rtc_irq)
? (cmos_rtc.mon_alrm
? "year"
: (cmos_rtc.day_alrm
? "month" : "day"))
: "no",
cmos_rtc.century ? ", y3k" : ""
);
return 0;
cleanup1:
rename_region(ports, NULL);
cleanup0:
rtc_device_unregister(cmos_rtc.rtc);
return retval;
}
static void cmos_do_shutdown(void)
{
unsigned char rtc_control;
spin_lock_irq(&rtc_lock);
rtc_control = CMOS_READ(RTC_CONTROL);
rtc_control &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
CMOS_WRITE(rtc_control, RTC_CONTROL);
CMOS_READ(RTC_INTR_FLAGS);
spin_unlock_irq(&rtc_lock);
}
static void __exit cmos_do_remove(struct device *dev)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
cmos_do_shutdown();
if (is_pnpacpi())
release_resource(cmos->iomem);
rename_region(cmos->iomem, NULL);
if (is_valid_irq(cmos->irq))
free_irq(cmos->irq, &cmos_rtc.rtc->class_dev);
rtc_device_unregister(cmos_rtc.rtc);
cmos_rtc.dev = NULL;
dev_set_drvdata(dev, NULL);
}
#ifdef CONFIG_PM
static int cmos_suspend(struct device *dev, pm_message_t mesg)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
int do_wake = device_may_wakeup(dev);
unsigned char tmp, irqstat;
/* only the alarm might be a wakeup event source */
spin_lock_irq(&rtc_lock);
cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);
if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
if (do_wake)
tmp &= ~(RTC_PIE|RTC_UIE);
else
tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);
CMOS_WRITE(tmp, RTC_CONTROL);
irqstat = CMOS_READ(RTC_INTR_FLAGS);
} else
irqstat = 0;
spin_unlock_irq(&rtc_lock);
if (irqstat)
rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat);
/* ACPI HOOK: enable ACPI_EVENT_RTC when (tmp & RTC_AIE)
* ... it'd be best if we could do that under rtc_lock.
*/
pr_debug("%s: suspend%s, ctrl %02x\n",
cmos_rtc.rtc->class_dev.class_id,
(tmp & RTC_AIE) ? ", alarm may wake" : "",
tmp);
return 0;
}
static int cmos_resume(struct device *dev)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char tmp = cmos->suspend_ctrl;
/* REVISIT: a mechanism to resync the system clock (jiffies)
* on resume should be portable between platforms ...
*/
/* re-enable any irqs previously active */
if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {
/* ACPI HOOK: disable ACPI_EVENT_RTC when (tmp & RTC_AIE) */
spin_lock_irq(&rtc_lock);
CMOS_WRITE(tmp, RTC_CONTROL);
tmp = CMOS_READ(RTC_INTR_FLAGS);
spin_unlock_irq(&rtc_lock);
if (tmp)
rtc_update_irq(&cmos->rtc->class_dev, 1, tmp);
}
pr_debug("%s: resume, ctrl %02x\n",
cmos_rtc.rtc->class_dev.class_id,
cmos->suspend_ctrl);
return 0;
}
#else
#define cmos_suspend NULL
#define cmos_resume NULL
#endif
/*----------------------------------------------------------------*/
/* The "CMOS" RTC normally lives on the platform_bus. On ACPI systems,
* the device node may alternatively be created as a PNP device.
*/
#ifdef CONFIG_PNPACPI
#include <linux/pnp.h>
static int __devinit
cmos_pnp_probe(struct pnp_dev *pnp, const struct pnp_device_id *id)
{
/* REVISIT paranoia argues for a shutdown notifier, since PNP
* drivers can't provide shutdown() methods to disable IRQs.
* Or better yet, fix PNP to allow those methods...
*/
return cmos_do_probe(&pnp->dev,
&pnp->res.port_resource[0],
pnp->res.irq_resource[0].start);
}
static void __exit cmos_pnp_remove(struct pnp_dev *pnp)
{
cmos_do_remove(&pnp->dev);
}
#ifdef CONFIG_PM
static int cmos_pnp_suspend(struct pnp_dev *pnp, pm_message_t mesg)
{
return cmos_suspend(&pnp->dev, mesg);
}
static int cmos_pnp_resume(struct pnp_dev *pnp)
{
return cmos_resume(&pnp->dev);
}
#else
#define cmos_pnp_suspend NULL
#define cmos_pnp_resume NULL
#endif
static const struct pnp_device_id rtc_ids[] = {
{ .id = "PNP0b00", },
{ .id = "PNP0b01", },
{ .id = "PNP0b02", },
{ },
};
MODULE_DEVICE_TABLE(pnp, rtc_ids);
static struct pnp_driver cmos_pnp_driver = {
.name = (char *) driver_name,
.id_table = rtc_ids,
.probe = cmos_pnp_probe,
.remove = __exit_p(cmos_pnp_remove),
/* flag ensures resume() gets called, and stops syslog spam */
.flags = PNP_DRIVER_RES_DO_NOT_CHANGE,
.suspend = cmos_pnp_suspend,
.resume = cmos_pnp_resume,
};
static int __init cmos_init(void)
{
return pnp_register_driver(&cmos_pnp_driver);
}
module_init(cmos_init);
static void __exit cmos_exit(void)
{
pnp_unregister_driver(&cmos_pnp_driver);
}
module_exit(cmos_exit);
#else /* no PNPACPI */
/*----------------------------------------------------------------*/
/* Platform setup should have set up an RTC device, when PNPACPI is
* unavailable ... this is the normal case, common even on PCs.
*/
static int __init cmos_platform_probe(struct platform_device *pdev)
{
return cmos_do_probe(&pdev->dev,
platform_get_resource(pdev, IORESOURCE_IO, 0),
platform_get_irq(pdev, 0));
}
static int __exit cmos_platform_remove(struct platform_device *pdev)
{
cmos_do_remove(&pdev->dev);
return 0;
}
static void cmos_platform_shutdown(struct platform_device *pdev)
{
cmos_do_shutdown();
}
static struct platform_driver cmos_platform_driver = {
.remove = __exit_p(cmos_platform_remove),
.shutdown = cmos_platform_shutdown,
.driver = {
.name = (char *) driver_name,
.suspend = cmos_suspend,
.resume = cmos_resume,
}
};
static int __init cmos_init(void)
{
return platform_driver_probe(&cmos_platform_driver,
cmos_platform_probe);
}
module_init(cmos_init);
static void __exit cmos_exit(void)
{
platform_driver_unregister(&cmos_platform_driver);
}
module_exit(cmos_exit);
#endif /* !PNPACPI */
MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("Driver for PC-style 'CMOS' RTCs");
MODULE_LICENSE("GPL");
