/* * drivers/base/power/sysfs.c - sysfs entries for device PM */ #include #include #include #include "power.h" /* * control - Report/change current runtime PM setting of the device * * Runtime power management of a device can be blocked with the help of * this attribute. All devices have one of the following two values for * the power/control file: * * + "auto\n" to allow the device to be power managed at run time; * + "on\n" to prevent the device from being power managed at run time; * * The default for all devices is "auto", which means that devices may be * subject to automatic power management, depending on their drivers. * Changing this attribute to "on" prevents the driver from power managing * the device at run time. Doing that while the device is suspended causes * it to be woken up. * * 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. * * async - Report/change current async suspend setting for the device * * Asynchronous suspend and resume of the device during system-wide power * state transitions can be enabled by writing "enabled" to this file. * Analogously, if "disabled" is written to this file, the device will be * suspended and resumed synchronously. * * All devices have one of the following two values for power/async: * * + "enabled\n" to permit the asynchronous suspend/resume of the device; * + "disabled\n" to forbid it; * * NOTE: It generally is unsafe to permit the asynchronous suspend/resume * of a device unless it is certain that all of the PM dependencies of the * device are known to the PM core. However, for some devices this * attribute is set to "enabled" by bus type code or device drivers and in * that cases it should be safe to leave the default value. */ static const char enabled[] = "enabled"; static const char disabled[] = "disabled"; #ifdef CONFIG_PM_RUNTIME static const char ctrl_auto[] = "auto"; static const char ctrl_on[] = "on"; static ssize_t control_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", dev->power.runtime_auto ? ctrl_auto : ctrl_on); } static ssize_t control_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t n) { char *cp; int len = n; cp = memchr(buf, '\n', n); if (cp) len = cp - buf; if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0) pm_runtime_allow(dev); else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0) pm_runtime_forbid(dev); else return -EINVAL; return n; } static DEVICE_ATTR(control, 0644, control_show, control_store); #endif 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); #ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG static ssize_t async_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", device_async_suspend_enabled(dev) ? enabled : disabled); } static ssize_t async_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { char *cp; int len = n; cp = memchr(buf, '\n', n); if (cp) len = cp - buf; if (len == sizeof enabled - 1 && strncmp(buf, enabled, len) == 0) device_enable_async_suspend(dev); else if (len == sizeof disabled - 1 && strncmp(buf, disabled, len) == 0) device_disable_async_suspend(dev); else return -EINVAL; return n; } static DEVICE_ATTR(async, 0644, async_show, async_store); #endif /* CONFIG_PM_SLEEP_ADVANCED_DEBUG */ static struct attribute * power_attrs[] = { #ifdef CONFIG_PM_RUNTIME &dev_attr_control.attr, #endif &dev_attr_wakeup.attr, #ifdef CONFIG_PM_SLEEP_ADVANCED_DEBUG &dev_attr_async.attr, #endif NULL, }; static struct attribute_group pm_attr_group = { .name = "power", .attrs = power_attrs, }; int dpm_sysfs_add(struct device * dev) { return sysfs_create_group(&dev->kobj, &pm_attr_group); } void dpm_sysfs_remove(struct device * dev) { sysfs_remove_group(&dev->kobj, &pm_attr_group); }