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linux/drivers/rtc/rtc-ds1553.c
David Brownell 743e6a504f rtc: file close() consistently disables repeating irqs 
Make the rtc framework consistent about disabling 1/second update IRQs
that may have been activated through the /dev interface, when that /dev
file is closed.  (It may have closed because of coredump, etc.) This was
previously done only for emulated update IRQs ...  now, do it always.

Also comment the current policy: repeating IRQs (periodic, update) that
userspace enabled will be cleanly disabled, but alarms are left alone.
Such repeating IRQs are a constant and pointless system load.

Update some RTC drivers to remove now-needless release() methods.  Most
such methods just enforce that policy.  The others all seem to be buggy,
and mistreat in-kernel clients of periodic or alarm IRQs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Andrew Sharp <andy.sharp@onstor.com>
Cc: Angelo Castello <angelo.castello@st.com>
Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
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>
2008-10-16 11:21:40 -07:00

411 lines
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/*
* An rtc driver for the Dallas DS1553
*
* Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/bcd.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#define DRV_VERSION "0.2"
#define RTC_REG_SIZE 0x2000
#define RTC_OFFSET 0x1ff0
#define RTC_FLAGS (RTC_OFFSET + 0)
#define RTC_SECONDS_ALARM (RTC_OFFSET + 2)
#define RTC_MINUTES_ALARM (RTC_OFFSET + 3)
#define RTC_HOURS_ALARM (RTC_OFFSET + 4)
#define RTC_DATE_ALARM (RTC_OFFSET + 5)
#define RTC_INTERRUPTS (RTC_OFFSET + 6)
#define RTC_WATCHDOG (RTC_OFFSET + 7)
#define RTC_CONTROL (RTC_OFFSET + 8)
#define RTC_CENTURY (RTC_OFFSET + 8)
#define RTC_SECONDS (RTC_OFFSET + 9)
#define RTC_MINUTES (RTC_OFFSET + 10)
#define RTC_HOURS (RTC_OFFSET + 11)
#define RTC_DAY (RTC_OFFSET + 12)
#define RTC_DATE (RTC_OFFSET + 13)
#define RTC_MONTH (RTC_OFFSET + 14)
#define RTC_YEAR (RTC_OFFSET + 15)
#define RTC_CENTURY_MASK 0x3f
#define RTC_SECONDS_MASK 0x7f
#define RTC_DAY_MASK 0x07
/* Bits in the Control/Century register */
#define RTC_WRITE 0x80
#define RTC_READ 0x40
/* Bits in the Seconds register */
#define RTC_STOP 0x80
/* Bits in the Flags register */
#define RTC_FLAGS_AF 0x40
#define RTC_FLAGS_BLF 0x10
/* Bits in the Interrupts register */
#define RTC_INTS_AE 0x80
struct rtc_plat_data {
struct rtc_device *rtc;
void __iomem *ioaddr;
resource_size_t baseaddr;
unsigned long last_jiffies;
int irq;
unsigned int irqen;
int alrm_sec;
int alrm_min;
int alrm_hour;
int alrm_mday;
};
static int ds1553_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
u8 century;
century = BIN2BCD((tm->tm_year + 1900) / 100);
writeb(RTC_WRITE, pdata->ioaddr + RTC_CONTROL);
writeb(BIN2BCD(tm->tm_year % 100), ioaddr + RTC_YEAR);
writeb(BIN2BCD(tm->tm_mon + 1), ioaddr + RTC_MONTH);
writeb(BIN2BCD(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
writeb(BIN2BCD(tm->tm_mday), ioaddr + RTC_DATE);
writeb(BIN2BCD(tm->tm_hour), ioaddr + RTC_HOURS);
writeb(BIN2BCD(tm->tm_min), ioaddr + RTC_MINUTES);
writeb(BIN2BCD(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
/* RTC_CENTURY and RTC_CONTROL share same register */
writeb(RTC_WRITE | (century & RTC_CENTURY_MASK), ioaddr + RTC_CENTURY);
writeb(century & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
return 0;
}
static int ds1553_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned int year, month, day, hour, minute, second, week;
unsigned int century;
/* give enough time to update RTC in case of continuous read */
if (pdata->last_jiffies == jiffies)
msleep(1);
pdata->last_jiffies = jiffies;
writeb(RTC_READ, ioaddr + RTC_CONTROL);
second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
minute = readb(ioaddr + RTC_MINUTES);
hour = readb(ioaddr + RTC_HOURS);
day = readb(ioaddr + RTC_DATE);
week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
month = readb(ioaddr + RTC_MONTH);
year = readb(ioaddr + RTC_YEAR);
century = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
writeb(0, ioaddr + RTC_CONTROL);
tm->tm_sec = BCD2BIN(second);
tm->tm_min = BCD2BIN(minute);
tm->tm_hour = BCD2BIN(hour);
tm->tm_mday = BCD2BIN(day);
tm->tm_wday = BCD2BIN(week);
tm->tm_mon = BCD2BIN(month) - 1;
/* year is 1900 + tm->tm_year */
tm->tm_year = BCD2BIN(year) + BCD2BIN(century) * 100 - 1900;
if (rtc_valid_tm(tm) < 0) {
dev_err(dev, "retrieved date/time is not valid.\n");
rtc_time_to_tm(0, tm);
}
return 0;
}
static void ds1553_rtc_update_alarm(struct rtc_plat_data *pdata)
{
void __iomem *ioaddr = pdata->ioaddr;
unsigned long flags;
spin_lock_irqsave(&pdata->rtc->irq_lock, flags);
writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
0x80 : BIN2BCD(pdata->alrm_mday),
ioaddr + RTC_DATE_ALARM);
writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
0x80 : BIN2BCD(pdata->alrm_hour),
ioaddr + RTC_HOURS_ALARM);
writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
0x80 : BIN2BCD(pdata->alrm_min),
ioaddr + RTC_MINUTES_ALARM);
writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
0x80 : BIN2BCD(pdata->alrm_sec),
ioaddr + RTC_SECONDS_ALARM);
writeb(pdata->irqen ? RTC_INTS_AE : 0, ioaddr + RTC_INTERRUPTS);
readb(ioaddr + RTC_FLAGS); /* clear interrupts */
spin_unlock_irqrestore(&pdata->rtc->irq_lock, flags);
}
static int ds1553_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq < 0)
return -EINVAL;
pdata->alrm_mday = alrm->time.tm_mday;
pdata->alrm_hour = alrm->time.tm_hour;
pdata->alrm_min = alrm->time.tm_min;
pdata->alrm_sec = alrm->time.tm_sec;
if (alrm->enabled)
pdata->irqen |= RTC_AF;
ds1553_rtc_update_alarm(pdata);
return 0;
}
static int ds1553_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq < 0)
return -EINVAL;
alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
return 0;
}
static irqreturn_t ds1553_rtc_interrupt(int irq, void *dev_id)
{
struct platform_device *pdev = dev_id;
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
unsigned long events = RTC_IRQF;
/* read and clear interrupt */
if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
return IRQ_NONE;
if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
events |= RTC_UF;
else
events |= RTC_AF;
rtc_update_irq(pdata->rtc, 1, events);
return IRQ_HANDLED;
}
static int ds1553_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
struct platform_device *pdev = to_platform_device(dev);
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
if (pdata->irq < 0)
return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
switch (cmd) {
case RTC_AIE_OFF:
pdata->irqen &= ~RTC_AF;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_AIE_ON:
pdata->irqen |= RTC_AF;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_UIE_OFF:
pdata->irqen &= ~RTC_UF;
ds1553_rtc_update_alarm(pdata);
break;
case RTC_UIE_ON:
pdata->irqen |= RTC_UF;
ds1553_rtc_update_alarm(pdata);
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static const struct rtc_class_ops ds1553_rtc_ops = {
.read_time = ds1553_rtc_read_time,
.set_time = ds1553_rtc_set_time,
.read_alarm = ds1553_rtc_read_alarm,
.set_alarm = ds1553_rtc_set_alarm,
.ioctl = ds1553_rtc_ioctl,
};
static ssize_t ds1553_nvram_read(struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
struct platform_device *pdev =
to_platform_device(container_of(kobj, struct device, kobj));
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
*buf++ = readb(ioaddr + pos++);
return count;
}
static ssize_t ds1553_nvram_write(struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t size)
{
struct platform_device *pdev =
to_platform_device(container_of(kobj, struct device, kobj));
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
void __iomem *ioaddr = pdata->ioaddr;
ssize_t count;
for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
writeb(*buf++, ioaddr + pos++);
return count;
}
static struct bin_attribute ds1553_nvram_attr = {
.attr = {
.name = "nvram",
.mode = S_IRUGO | S_IWUSR,
},
.size = RTC_OFFSET,
.read = ds1553_nvram_read,
.write = ds1553_nvram_write,
};
static int __devinit ds1553_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
struct resource *res;
unsigned int cen, sec;
struct rtc_plat_data *pdata = NULL;
void __iomem *ioaddr = NULL;
int ret = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENODEV;
pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
if (!pdata)
return -ENOMEM;
pdata->irq = -1;
if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
ret = -EBUSY;
goto out;
}
pdata->baseaddr = res->start;
ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);
if (!ioaddr) {
ret = -ENOMEM;
goto out;
}
pdata->ioaddr = ioaddr;
pdata->irq = platform_get_irq(pdev, 0);
/* turn RTC on if it was not on */
sec = readb(ioaddr + RTC_SECONDS);
if (sec & RTC_STOP) {
sec &= RTC_SECONDS_MASK;
cen = readb(ioaddr + RTC_CENTURY) & RTC_CENTURY_MASK;
writeb(RTC_WRITE, ioaddr + RTC_CONTROL);
writeb(sec, ioaddr + RTC_SECONDS);
writeb(cen & RTC_CENTURY_MASK, ioaddr + RTC_CONTROL);
}
if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_BLF)
dev_warn(&pdev->dev, "voltage-low detected.\n");
if (pdata->irq >= 0) {
writeb(0, ioaddr + RTC_INTERRUPTS);
if (request_irq(pdata->irq, ds1553_rtc_interrupt,
IRQF_DISABLED | IRQF_SHARED,
pdev->name, pdev) < 0) {
dev_warn(&pdev->dev, "interrupt not available.\n");
pdata->irq = -1;
}
}
rtc = rtc_device_register(pdev->name, &pdev->dev,
&ds1553_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc)) {
ret = PTR_ERR(rtc);
goto out;
}
pdata->rtc = rtc;
pdata->last_jiffies = jiffies;
platform_set_drvdata(pdev, pdata);
ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
if (ret)
goto out;
return 0;
out:
if (pdata->rtc)
rtc_device_unregister(pdata->rtc);
if (pdata->irq >= 0)
free_irq(pdata->irq, pdev);
if (ioaddr)
iounmap(ioaddr);
if (pdata->baseaddr)
release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
kfree(pdata);
return ret;
}
static int __devexit ds1553_rtc_remove(struct platform_device *pdev)
{
struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
sysfs_remove_bin_file(&pdev->dev.kobj, &ds1553_nvram_attr);
rtc_device_unregister(pdata->rtc);
if (pdata->irq >= 0) {
writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
free_irq(pdata->irq, pdev);
}
iounmap(pdata->ioaddr);
release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
kfree(pdata);
return 0;
}
/* work with hotplug and coldplug */
MODULE_ALIAS("platform:rtc-ds1553");
static struct platform_driver ds1553_rtc_driver = {
.probe = ds1553_rtc_probe,
.remove = __devexit_p(ds1553_rtc_remove),
.driver = {
.name = "rtc-ds1553",
.owner = THIS_MODULE,
},
};
static __init int ds1553_init(void)
{
return platform_driver_register(&ds1553_rtc_driver);
}
static __exit void ds1553_exit(void)
{
platform_driver_unregister(&ds1553_rtc_driver);
}
module_init(ds1553_init);
module_exit(ds1553_exit);
MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
MODULE_DESCRIPTION("Dallas DS1553 RTC driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);
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