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Commit 97144c67 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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rtc_irq_set_freq() requires power-of-two and associated kerneldoc 



RTC periodic IRQs are only defined to work for 2^N Hz values.  This patch
moves that validity check into the infrastructure, so drivers don't need to
check it; and adds kerneldoc for the two interface functions related to
periodic IRQs.  (One of which was quite mysterious until its first use was
recently checked in!)

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d691eb90

drivers/rtc/interface.c

+24 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
*/



#include <linux/rtc.h>

#include <linux/log2.h>



int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)

{
@@ -236,6 +237,16 @@ void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) 
}

EXPORT_SYMBOL_GPL(rtc_irq_unregister);



/**

 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs

 * @rtc: the rtc device

 * @task: currently registered with rtc_irq_register()

 * @enabled: true to enable periodic IRQs

 * Context: any

 *

 * Note that rtc_irq_set_freq() should previously have been used to

 * specify the desired frequency of periodic IRQ task->func() callbacks.

 */

int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)

{

	int err = 0;
@@ -258,6 +269,16 @@ int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled 
}

EXPORT_SYMBOL_GPL(rtc_irq_set_state);



/**

 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ

 * @rtc: the rtc device

 * @task: currently registered with rtc_irq_register()

 * @freq: positive frequency with which task->func() will be called

 * Context: any

 *

 * Note that rtc_irq_set_state() is used to enable or disable the

 * periodic IRQs.

 */

int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)

{

	int err = 0;
@@ -266,6 +287,9 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) 
	if (rtc->ops->irq_set_freq == NULL)

		return -ENXIO;



	if (!is_power_of_2(freq))

		return -EINVAL;



	spin_lock_irqsave(&rtc->irq_task_lock, flags);

	if (rtc->irq_task != NULL && task == NULL)

		err = -EBUSY;

drivers/rtc/rtc-cmos.c

+3 −5
Original line number Diff line number Diff line
@@ -246,11 +246,9 @@ static int cmos_irq_set_freq(struct device *dev, int freq) 


	/* 0 = no irqs; 1 = 2^15 Hz ... 15 = 2^0 Hz */

	f = ffs(freq);

	if (f != 0) {

		if (f-- > 16 || freq != (1 << f))

	if (f-- > 16)

		return -EINVAL;

	f = 16 - f;

	}



	spin_lock_irqsave(&rtc_lock, flags);

	CMOS_WRITE(RTC_REF_CLCK_32KHZ | f, RTC_FREQ_SELECT);