Commit 0ac85241 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
Browse files

[PATCH] driver model wakeup flags 



This is a refresh of an earlier patch to add "wakeup" support to the
PM core model.  This provides per-device bus-neutral control of the
use of wakeup events.

  * "struct device_pm_info" has two bits that are initialized as
    part of setting up the enclosing struct device:
      - "can_wakeup", reflecting hardware capabilities
      - "may_wakeup", the policy setting (when CONFIG_PM)

  * There's a writeable sysfs "wakeup" file, with one of two values:
      - "enabled", when the policy is to allow wakeup
      - "disabled", when the policy is not to allow it
      - "" if the device can't currently issue wakeups

By default, wakeup is enabled on all devices that support it.  If its
driver doesn't support it ... treat it as a bug.  :)

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 2a7ff1fe

drivers/base/core.c

+1 −0
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ void device_initialize(struct device *dev) 
		   klist_children_put);

	INIT_LIST_HEAD(&dev->dma_pools);

	init_MUTEX(&dev->sem);

	device_init_wakeup(dev, 0);

}



/**

drivers/base/power/sysfs.c

+73 −0
Original line number Diff line number Diff line
@@ -48,8 +48,81 @@ static ssize_t state_store(struct device * dev, struct device_attribute *attr, c 
static DEVICE_ATTR(state, 0644, state_show, state_store);





/*

 *	wakeup - Report/change current wakeup option for device

 *

 *	Some devices support "wakeup" events, which are hardware signals

 *	used to activate devices from suspended or low power states.  Such

 *	devices have one of three values for the sysfs power/wakeup file:

 *

 *	 + "enabled\n" to issue the events;

 *	 + "disabled\n" not to do so; or

 *	 + "\n" for temporary or permanent inability to issue wakeup.

 *

 *	(For example, unconfigured USB devices can't issue wakeups.)

 *

 *	Familiar examples of devices that can issue wakeup events include

 *	keyboards and mice (both PS2 and USB styles), power buttons, modems,

 *	"Wake-On-LAN" Ethernet links, GPIO lines, and more.  Some events

 *	will wake the entire system from a suspend state; others may just

 *	wake up the device (if the system as a whole is already active).

 *	Some wakeup events use normal IRQ lines; other use special out

 *	of band signaling.

 *

 *	It is the responsibility of device drivers to enable (or disable)

 *	wakeup signaling as part of changing device power states, respecting

 *	the policy choices provided through the driver model.

 *

 *	Devices may not be able to generate wakeup events from all power

 *	states.  Also, the events may be ignored in some configurations;

 *	for example, they might need help from other devices that aren't

 *	active, or which may have wakeup disabled.  Some drivers rely on

 *	wakeup events internally (unless they are disabled), keeping

 *	their hardware in low power modes whenever they're unused.  This

 *	saves runtime power, without requiring system-wide sleep states.

 */



static const char enabled[] = "enabled";

static const char disabled[] = "disabled";



static ssize_t

wake_show(struct device * dev, struct device_attribute *attr, char * buf)

{

	return sprintf(buf, "%s\n", device_can_wakeup(dev)

		? (device_may_wakeup(dev) ? enabled : disabled)

		: "");

}



static ssize_t

wake_store(struct device * dev, struct device_attribute *attr,

	const char * buf, size_t n)

{

	char *cp;

	int len = n;



	if (!device_can_wakeup(dev))

		return -EINVAL;



	cp = memchr(buf, '\n', n);

	if (cp)

		len = cp - buf;

	if (len == sizeof enabled - 1

			&& strncmp(buf, enabled, sizeof enabled - 1) == 0)

		device_set_wakeup_enable(dev, 1);

	else if (len == sizeof disabled - 1

			&& strncmp(buf, disabled, sizeof disabled - 1) == 0)

		device_set_wakeup_enable(dev, 0);

	else

		return -EINVAL;

	return n;

}



static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);





static struct attribute * power_attrs[] = {

	&dev_attr_state.attr,

	&dev_attr_wakeup.attr,

	NULL,

};

static struct attribute_group pm_attr_group = {

include/linux/pm.h

+25 −1
Original line number Diff line number Diff line
@@ -219,7 +219,9 @@ typedef struct pm_message { 


struct dev_pm_info {

	pm_message_t		power_state;

	unsigned		can_wakeup:1;

#ifdef	CONFIG_PM

	unsigned		should_wakeup:1;

	pm_message_t		prev_state;

	void			* saved_state;

	atomic_t		pm_users;
@@ -236,13 +238,35 @@ extern void device_resume(void); 


#ifdef CONFIG_PM

extern int device_suspend(pm_message_t state);

#else



#define device_set_wakeup_enable(dev,val) \

	((dev)->power.should_wakeup = !!(val))

#define device_may_wakeup(dev) \

	(device_can_wakeup(dev) && (dev)->power.should_wakeup)



#else /* !CONFIG_PM */



static inline int device_suspend(pm_message_t state)

{

	return 0;

}



#define device_set_wakeup_enable(dev,val)	do{}while(0)

#define device_may_wakeup(dev)			(0)



#endif



/* changes to device_may_wakeup take effect on the next pm state change.

 * by default, devices should wakeup if they can.

 */

#define device_can_wakeup(dev) \

	((dev)->power.can_wakeup)

#define device_init_wakeup(dev,val) \

	do { \

		device_can_wakeup(dev) = !!(val); \

		device_set_wakeup_enable(dev,val); \

	} while(0)



#endif /* __KERNEL__ */



#endif /* _LINUX_PM_H */

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