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

[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
......@@ -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);
}
/**
......
......@@ -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 = {
......
......@@ -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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