PCI ACPI: Rework PCI handling of wake-up

[linux-2.6-omap-h63xx.git] / drivers / base / power / sysfs.c

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 8d04fb435c176ebc92f89793cb5998d05721694b..596aeecfdffe4be62c7e6773046e9c23d4dd37bb 100644 (file)
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -3,53 +3,83 @@
  */
 
 #include <linux/device.h>
+#include <linux/string.h>
 #include "power.h"
 
-
-/**
- *     state - Control current power state of device
+/*
+ *     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.)
  *
- *     show() returns the current power state of the device. '0' indicates
- *     the device is on. Other values (1-3) indicate the device is in a low
- *     power state.
+ *     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.
  *
- *     store() sets the current power state, which is an integer value
- *     between 0-3. If the device is on ('0'), and the value written is
- *     greater than 0, then the device is placed directly into the low-power
- *     state (via its driver's ->suspend() method).
- *     If the device is currently in a low-power state, and the value is 0,
- *     the device is powered back on (via the ->resume() method).
- *     If the device is in a low-power state, and a different low-power state
- *     is requested, the device is first resumed, then suspended into the new
- *     low-power state.
+ *     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 ssize_t state_show(struct device * dev, struct device_attribute *attr, char * buf)
+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, "%u\n", dev->power.power_state.event);
+       return sprintf(buf, "%s\n", device_can_wakeup(dev)
+               ? (device_may_wakeup(dev) ? enabled : disabled)
+               : "");
 }
 
-static ssize_t state_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t n)
+static ssize_t
+wake_store(struct device * dev, struct device_attribute *attr,
+       const char * buf, size_t n)
 {
-       pm_message_t state;
-       char * rest;
-       int error = 0;
+       char *cp;
+       int len = n;
 
-       state.event = simple_strtoul(buf, &rest, 10);
-       if (*rest)
+       if (!device_can_wakeup(dev))
                return -EINVAL;
-       if (state.event)
-               error = dpm_runtime_suspend(dev, state);
+
+       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
-               dpm_runtime_resume(dev);
-       return error ? error : n;
+               return -EINVAL;
+       return n;
 }
 
-static DEVICE_ATTR(state, 0644, state_show, state_store);
+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 = {