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[PATCH] RTC: rtc-dev UIE emulation

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Import genrtc's RTC UIE emulation (CONFIG_GEN_RTC_X) to rtc-dev driver with
slight adjustments/refinements.  This makes UIE-less rtc drivers work
better with programs doing read/poll on /dev/rtc, such as hwclock.  This
emulation should not harm rtc drivers with UIE support, since
rtc_dev_ioctl() calls underlaying rtc driver's ioctl() first.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Atsushi Nemoto 2006-06-25 05:48:17 -07:00 committed by Linus Torvalds
parent 1abb0dc92d
commit 655066c383
3 changed files with 119 additions and 0 deletions
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7
drivers/rtc/Kconfig
View file

@ -73,6 +73,13 @@ config RTC_INTF_DEV
This driver can also be built as a module. If so, the module
will be called rtc-dev.
config RTC_INTF_DEV_UIE_EMUL
bool "RTC UIE emulation on dev interface"
depends on RTC_INTF_DEV
help
Provides an emulation for RTC_UIE if the underlaying rtc chip
driver did not provide RTC_UIE ioctls.
comment "RTC drivers"
depends on RTC_CLASS

102
drivers/rtc/rtc-dev.c
View file

@ -48,6 +48,93 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
return err;
}
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
/*
* Routine to poll RTC seconds field for change as often as possible,
* after first RTC_UIE use timer to reduce polling
*/
static void rtc_uie_task(void *data)
{
struct rtc_device *rtc = data;
struct rtc_time tm;
int num = 0;
int err;
err = rtc_read_time(&rtc->class_dev, &tm);
spin_lock_irq(&rtc->irq_lock);
if (rtc->stop_uie_polling || err) {
rtc->uie_task_active = 0;
} else if (rtc->oldsecs != tm.tm_sec) {
num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;
rtc->oldsecs = tm.tm_sec;
rtc->uie_timer.expires = jiffies + HZ - (HZ/10);
rtc->uie_timer_active = 1;
rtc->uie_task_active = 0;
add_timer(&rtc->uie_timer);
} else if (schedule_work(&rtc->uie_task) == 0) {
rtc->uie_task_active = 0;
}
spin_unlock_irq(&rtc->irq_lock);
if (num)
rtc_update_irq(&rtc->class_dev, num, RTC_UF | RTC_IRQF);
}
static void rtc_uie_timer(unsigned long data)
{
struct rtc_device *rtc = (struct rtc_device *)data;
unsigned long flags;
spin_lock_irqsave(&rtc->irq_lock, flags);
rtc->uie_timer_active = 0;
rtc->uie_task_active = 1;
if ((schedule_work(&rtc->uie_task) == 0))
rtc->uie_task_active = 0;
spin_unlock_irqrestore(&rtc->irq_lock, flags);
}
static void clear_uie(struct rtc_device *rtc)
{
spin_lock_irq(&rtc->irq_lock);
if (rtc->irq_active) {
rtc->stop_uie_polling = 1;
if (rtc->uie_timer_active) {
spin_unlock_irq(&rtc->irq_lock);
del_timer_sync(&rtc->uie_timer);
spin_lock_irq(&rtc->irq_lock);
rtc->uie_timer_active = 0;
}
if (rtc->uie_task_active) {
spin_unlock_irq(&rtc->irq_lock);
flush_scheduled_work();
spin_lock_irq(&rtc->irq_lock);
}
rtc->irq_active = 0;
}
spin_unlock_irq(&rtc->irq_lock);
}
static int set_uie(struct rtc_device *rtc)
{
struct rtc_time tm;
int err;
err = rtc_read_time(&rtc->class_dev, &tm);
if (err)
return err;
spin_lock_irq(&rtc->irq_lock);
if (!rtc->irq_active) {
rtc->irq_active = 1;
rtc->stop_uie_polling = 0;
rtc->oldsecs = tm.tm_sec;
rtc->uie_task_active = 1;
if (schedule_work(&rtc->uie_task) == 0)
rtc->uie_task_active = 0;
}
rtc->irq_data = 0;
spin_unlock_irq(&rtc->irq_lock);
return 0;
}
#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */
static ssize_t
rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
@ -232,6 +319,14 @@ static int rtc_dev_ioctl(struct inode *inode, struct file *file,
return -EFAULT;
break;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
case RTC_UIE_OFF:
clear_uie(rtc);
return 0;
case RTC_UIE_ON:
return set_uie(rtc);
#endif
default:
err = -ENOTTY;
break;
@ -244,6 +339,9 @@ static int rtc_dev_release(struct inode *inode, struct file *file)
{
struct rtc_device *rtc = to_rtc_device(file->private_data);
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
clear_uie(rtc);
#endif
if (rtc->ops->release)
rtc->ops->release(rtc->class_dev.dev);
@ -284,6 +382,10 @@ static int rtc_dev_add_device(struct class_device *class_dev,
mutex_init(&rtc->char_lock);
spin_lock_init(&rtc->irq_lock);
init_waitqueue_head(&rtc->irq_queue);
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
INIT_WORK(&rtc->uie_task, rtc_uie_task, rtc);
setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc);
#endif
cdev_init(&rtc->char_dev, &rtc_dev_fops);
rtc->char_dev.owner = rtc->owner;

10
include/linux/rtc.h
View file

@ -155,6 +155,16 @@ struct rtc_device
struct rtc_task *irq_task;
spinlock_t irq_task_lock;
int irq_freq;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
/* Those fields are protected by rtc->irq_lock */
unsigned int oldsecs;
unsigned int irq_active:1;
unsigned int stop_uie_polling:1;
unsigned int uie_task_active:1;
unsigned int uie_timer_active:1;
#endif
};
#define to_rtc_device(d) container_of(d, struct rtc_device, class_dev)