[PATCH] driver model wakeup flags
From: Greg KH
Date: Fri Oct 28 2005 - 01:38:46 EST
[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: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
commit 79eef3cfd105168a2115fff06971af8efa27db82
tree 078336166c58694cab5086cc6b69443226985445
parent 409d93787e8cfec603d512c2925f8580c32a9d0a
author David Brownell <david-b@xxxxxxxxxxx> Mon, 12 Sep 2005 19:39:34 -0700
committer Greg Kroah-Hartman <gregkh@xxxxxxx> Thu, 27 Oct 2005 22:47:59 -0700
drivers/base/core.c | 1 +
drivers/base/power/sysfs.c | 73 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/pm.h | 26 +++++++++++++++-
3 files changed, 99 insertions(+), 1 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 6ab73f5..3110919 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -225,6 +225,7 @@ void device_initialize(struct device *de
klist_children_put);
INIT_LIST_HEAD(&dev->dma_pools);
init_MUTEX(&dev->sem);
+ device_init_wakeup(dev, 0);
}
/**
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 8d04fb4..89c5787 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -48,8 +48,81 @@ static ssize_t state_store(struct device
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 = {
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 5cfb076..7897cf5 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -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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