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21 results

trace_stack.c

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  • sysfs.c 21.09 KiB
    /*
     * drivers/base/power/sysfs.c - sysfs entries for device PM
     */
    
    #include <linux/device.h>
    #include <linux/string.h>
    #include <linux/export.h>
    #include <linux/pm_qos.h>
    #include <linux/pm_runtime.h>
    #include <linux/atomic.h>
    #include <linux/jiffies.h>
    #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.
     *
     *	autosuspend_delay_ms - Report/change a device's autosuspend_delay value
     *
     *	Some drivers don't want to carry out a runtime suspend as soon as a
     *	device becomes idle; they want it always to remain idle for some period
     *	of time before suspending it.  This period is the autosuspend_delay
     *	value (expressed in milliseconds) and it can be controlled by the user.
     *	If the value is negative then the device will never be runtime
     *	suspended.
     *
     *	NOTE: The autosuspend_delay_ms attribute and the autosuspend_delay
     *	value are used only if the driver calls pm_runtime_use_autosuspend().
     *
     *	wakeup_count - Report the number of wakeup events related to the device
     */
    
    const char power_group_name[] = "power";
    EXPORT_SYMBOL_GPL(power_group_name);
    
    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;
    	device_lock(dev);
    	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
    		n = -EINVAL;
    	device_unlock(dev);
    	return n;
    }
    
    static DEVICE_ATTR(control, 0644, control_show, control_store);
    
    static ssize_t rtpm_active_time_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	int ret;
    	spin_lock_irq(&dev->power.lock);
    	update_pm_runtime_accounting(dev);
    	ret = sprintf(buf, "%i\n", jiffies_to_msecs(dev->power.active_jiffies));
    	spin_unlock_irq(&dev->power.lock);
    	return ret;
    }
    
    static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);
    
    static ssize_t rtpm_suspended_time_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	int ret;
    	spin_lock_irq(&dev->power.lock);
    	update_pm_runtime_accounting(dev);
    	ret = sprintf(buf, "%i\n",
    		jiffies_to_msecs(dev->power.suspended_jiffies));
    	spin_unlock_irq(&dev->power.lock);
    	return ret;
    }
    
    static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);
    
    static ssize_t rtpm_status_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	const char *p;
    
    	if (dev->power.runtime_error) {
    		p = "error\n";
    	} else if (dev->power.disable_depth) {
    		p = "unsupported\n";
    	} else {
    		switch (dev->power.runtime_status) {
    		case RPM_SUSPENDED:
    			p = "suspended\n";
    			break;
    		case RPM_SUSPENDING:
    			p = "suspending\n";
    			break;
    		case RPM_RESUMING:
    			p = "resuming\n";
    			break;
    		case RPM_ACTIVE:
    			p = "active\n";
    			break;
    		default:
    			return -EIO;
    		}
    	}
    	return sprintf(buf, p);
    }
    
    static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL);
    
    static ssize_t autosuspend_delay_ms_show(struct device *dev,
    		struct device_attribute *attr, char *buf)
    {
    	if (!dev->power.use_autosuspend)
    		return -EIO;
    	return sprintf(buf, "%d\n", dev->power.autosuspend_delay);
    }
    
    static ssize_t autosuspend_delay_ms_store(struct device *dev,
    		struct device_attribute *attr, const char *buf, size_t n)
    {
    	long delay;
    
    	if (!dev->power.use_autosuspend)
    		return -EIO;
    
    	if (kstrtol(buf, 10, &delay) != 0 || delay != (int) delay)
    		return -EINVAL;
    
    	device_lock(dev);
    	pm_runtime_set_autosuspend_delay(dev, delay);
    	device_unlock(dev);
    	return n;
    }
    
    static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
    		autosuspend_delay_ms_store);
    
    static ssize_t pm_qos_resume_latency_show(struct device *dev,
    					  struct device_attribute *attr,
    					  char *buf)
    {
    	return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
    }
    
    static ssize_t pm_qos_resume_latency_store(struct device *dev,
    					   struct device_attribute *attr,
    					   const char *buf, size_t n)
    {
    	s32 value;
    	int ret;
    
    	if (kstrtos32(buf, 0, &value))
    		return -EINVAL;
    
    	if (value < 0)
    		return -EINVAL;
    
    	ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
    					value);
    	return ret < 0 ? ret : n;
    }
    
    static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
    		   pm_qos_resume_latency_show, pm_qos_resume_latency_store);
    
    static ssize_t pm_qos_latency_tolerance_show(struct device *dev,
    					     struct device_attribute *attr,
    					     char *buf)
    {
    	s32 value = dev_pm_qos_get_user_latency_tolerance(dev);
    
    	if (value < 0)
    		return sprintf(buf, "auto\n");
    	else if (value == PM_QOS_LATENCY_ANY)
    		return sprintf(buf, "any\n");
    
    	return sprintf(buf, "%d\n", value);
    }
    
    static ssize_t pm_qos_latency_tolerance_store(struct device *dev,
    					      struct device_attribute *attr,
    					      const char *buf, size_t n)
    {
    	s32 value;
    	int ret;
    
    	if (kstrtos32(buf, 0, &value) == 0) {
    		/* Users can't write negative values directly */
    		if (value < 0)
    			return -EINVAL;
    	} else {
    		if (!strcmp(buf, "auto") || !strcmp(buf, "auto\n"))
    			value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
    		else if (!strcmp(buf, "any") || !strcmp(buf, "any\n"))
    			value = PM_QOS_LATENCY_ANY;
    		else
    			return -EINVAL;
    	}
    	ret = dev_pm_qos_update_user_latency_tolerance(dev, value);
    	return ret < 0 ? ret : n;
    }
    
    static DEVICE_ATTR(pm_qos_latency_tolerance_us, 0644,
    		   pm_qos_latency_tolerance_show, pm_qos_latency_tolerance_store);
    
    static ssize_t pm_qos_no_power_off_show(struct device *dev,
    					struct device_attribute *attr,
    					char *buf)
    {
    	return sprintf(buf, "%d\n", !!(dev_pm_qos_requested_flags(dev)
    					& PM_QOS_FLAG_NO_POWER_OFF));
    }
    
    static ssize_t pm_qos_no_power_off_store(struct device *dev,
    					 struct device_attribute *attr,
    					 const char *buf, size_t n)
    {
    	int ret;
    
    	if (kstrtoint(buf, 0, &ret))
    		return -EINVAL;
    
    	if (ret != 0 && ret != 1)
    		return -EINVAL;
    
    	ret = dev_pm_qos_update_flags(dev, PM_QOS_FLAG_NO_POWER_OFF, ret);
    	return ret < 0 ? ret : n;
    }
    
    static DEVICE_ATTR(pm_qos_no_power_off, 0644,
    		   pm_qos_no_power_off_show, pm_qos_no_power_off_store);
    
    static ssize_t pm_qos_remote_wakeup_show(struct device *dev,
    					 struct device_attribute *attr,
    					 char *buf)
    {
    	return sprintf(buf, "%d\n", !!(dev_pm_qos_requested_flags(dev)
    					& PM_QOS_FLAG_REMOTE_WAKEUP));
    }
    
    static ssize_t pm_qos_remote_wakeup_store(struct device *dev,
    					  struct device_attribute *attr,
    					  const char *buf, size_t n)
    {
    	int ret;
    
    	if (kstrtoint(buf, 0, &ret))
    		return -EINVAL;
    
    	if (ret != 0 && ret != 1)
    		return -EINVAL;
    
    	ret = dev_pm_qos_update_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP, ret);
    	return ret < 0 ? ret : n;
    }
    
    static DEVICE_ATTR(pm_qos_remote_wakeup, 0644,
    		   pm_qos_remote_wakeup_show, pm_qos_remote_wakeup_store);
    
    #ifdef CONFIG_PM_SLEEP
    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 ssize_t wakeup_count_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	unsigned long count = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		count = dev->power.wakeup->event_count;
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
    
    static ssize_t wakeup_active_count_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	unsigned long count = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		count = dev->power.wakeup->active_count;
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);
    
    static ssize_t wakeup_abort_count_show(struct device *dev,
    					struct device_attribute *attr,
    					char *buf)
    {
    	unsigned long count = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		count = dev->power.wakeup->wakeup_count;
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_abort_count, 0444, wakeup_abort_count_show, NULL);
    
    static ssize_t wakeup_expire_count_show(struct device *dev,
    					struct device_attribute *attr,
    					char *buf)
    {
    	unsigned long count = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		count = dev->power.wakeup->expire_count;
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_expire_count, 0444, wakeup_expire_count_show, NULL);
    
    static ssize_t wakeup_active_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	unsigned int active = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		active = dev->power.wakeup->active;
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%u\n", active) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_active, 0444, wakeup_active_show, NULL);
    
    static ssize_t wakeup_total_time_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	s64 msec = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		msec = ktime_to_ms(dev->power.wakeup->total_time);
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_total_time_ms, 0444, wakeup_total_time_show, NULL);
    
    static ssize_t wakeup_max_time_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	s64 msec = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		msec = ktime_to_ms(dev->power.wakeup->max_time);
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_max_time_ms, 0444, wakeup_max_time_show, NULL);
    
    static ssize_t wakeup_last_time_show(struct device *dev,
    				struct device_attribute *attr, char *buf)
    {
    	s64 msec = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		msec = ktime_to_ms(dev->power.wakeup->last_time);
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_last_time_ms, 0444, wakeup_last_time_show, NULL);
    
    #ifdef CONFIG_PM_AUTOSLEEP
    static ssize_t wakeup_prevent_sleep_time_show(struct device *dev,
    					      struct device_attribute *attr,
    					      char *buf)
    {
    	s64 msec = 0;
    	bool enabled = false;
    
    	spin_lock_irq(&dev->power.lock);
    	if (dev->power.wakeup) {
    		msec = ktime_to_ms(dev->power.wakeup->prevent_sleep_time);
    		enabled = true;
    	}
    	spin_unlock_irq(&dev->power.lock);
    	return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
    }
    
    static DEVICE_ATTR(wakeup_prevent_sleep_time_ms, 0444,
    		   wakeup_prevent_sleep_time_show, NULL);
    #endif /* CONFIG_PM_AUTOSLEEP */
    #endif /* CONFIG_PM_SLEEP */
    
    #ifdef CONFIG_PM_ADVANCED_DEBUG
    static ssize_t rtpm_usagecount_show(struct device *dev,
    				    struct device_attribute *attr, char *buf)
    {
    	return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
    }
    
    static ssize_t rtpm_children_show(struct device *dev,
    				  struct device_attribute *attr, char *buf)
    {
    	return sprintf(buf, "%d\n", dev->power.ignore_children ?
    		0 : atomic_read(&dev->power.child_count));
    }
    
    static ssize_t rtpm_enabled_show(struct device *dev,
    				 struct device_attribute *attr, char *buf)
    {
    	if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
    		return sprintf(buf, "disabled & forbidden\n");
    	else if (dev->power.disable_depth)
    		return sprintf(buf, "disabled\n");
    	else if (dev->power.runtime_auto == false)
    		return sprintf(buf, "forbidden\n");
    	return sprintf(buf, "enabled\n");
    }
    
    static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
    static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
    static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);
    
    #ifdef CONFIG_PM_SLEEP
    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 */
    #endif /* CONFIG_PM_ADVANCED_DEBUG */
    
    static struct attribute *power_attrs[] = {
    #ifdef CONFIG_PM_ADVANCED_DEBUG
    #ifdef CONFIG_PM_SLEEP
    	&dev_attr_async.attr,
    #endif
    	&dev_attr_runtime_status.attr,
    	&dev_attr_runtime_usage.attr,
    	&dev_attr_runtime_active_kids.attr,
    	&dev_attr_runtime_enabled.attr,
    #endif /* CONFIG_PM_ADVANCED_DEBUG */
    	NULL,
    };
    static const struct attribute_group pm_attr_group = {
    	.name	= power_group_name,
    	.attrs	= power_attrs,
    };
    
    static struct attribute *wakeup_attrs[] = {
    #ifdef CONFIG_PM_SLEEP
    	&dev_attr_wakeup.attr,
    	&dev_attr_wakeup_count.attr,
    	&dev_attr_wakeup_active_count.attr,
    	&dev_attr_wakeup_abort_count.attr,
    	&dev_attr_wakeup_expire_count.attr,
    	&dev_attr_wakeup_active.attr,
    	&dev_attr_wakeup_total_time_ms.attr,
    	&dev_attr_wakeup_max_time_ms.attr,
    	&dev_attr_wakeup_last_time_ms.attr,
    #ifdef CONFIG_PM_AUTOSLEEP
    	&dev_attr_wakeup_prevent_sleep_time_ms.attr,
    #endif
    #endif
    	NULL,
    };
    static const struct attribute_group pm_wakeup_attr_group = {
    	.name	= power_group_name,
    	.attrs	= wakeup_attrs,
    };
    
    static struct attribute *runtime_attrs[] = {
    #ifndef CONFIG_PM_ADVANCED_DEBUG
    	&dev_attr_runtime_status.attr,
    #endif
    	&dev_attr_control.attr,
    	&dev_attr_runtime_suspended_time.attr,
    	&dev_attr_runtime_active_time.attr,
    	&dev_attr_autosuspend_delay_ms.attr,
    	NULL,
    };
    static const struct attribute_group pm_runtime_attr_group = {
    	.name	= power_group_name,
    	.attrs	= runtime_attrs,
    };
    
    static struct attribute *pm_qos_resume_latency_attrs[] = {
    	&dev_attr_pm_qos_resume_latency_us.attr,
    	NULL,
    };
    static const struct attribute_group pm_qos_resume_latency_attr_group = {
    	.name	= power_group_name,
    	.attrs	= pm_qos_resume_latency_attrs,
    };
    
    static struct attribute *pm_qos_latency_tolerance_attrs[] = {
    	&dev_attr_pm_qos_latency_tolerance_us.attr,
    	NULL,
    };
    static const struct attribute_group pm_qos_latency_tolerance_attr_group = {
    	.name	= power_group_name,
    	.attrs	= pm_qos_latency_tolerance_attrs,
    };
    
    static struct attribute *pm_qos_flags_attrs[] = {
    	&dev_attr_pm_qos_no_power_off.attr,
    	&dev_attr_pm_qos_remote_wakeup.attr,
    	NULL,
    };
    static const struct attribute_group pm_qos_flags_attr_group = {
    	.name	= power_group_name,
    	.attrs	= pm_qos_flags_attrs,
    };
    
    int dpm_sysfs_add(struct device *dev)
    {
    	int rc;
    
    	rc = sysfs_create_group(&dev->kobj, &pm_attr_group);
    	if (rc)
    		return rc;
    
    	if (pm_runtime_callbacks_present(dev)) {
    		rc = sysfs_merge_group(&dev->kobj, &pm_runtime_attr_group);
    		if (rc)
    			goto err_out;
    	}
    	if (device_can_wakeup(dev)) {
    		rc = sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
    		if (rc)
    			goto err_runtime;
    	}
    	if (dev->power.set_latency_tolerance) {
    		rc = sysfs_merge_group(&dev->kobj,
    				       &pm_qos_latency_tolerance_attr_group);
    		if (rc)
    			goto err_wakeup;
    	}
    	return 0;
    
     err_wakeup:
    	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
     err_runtime:
    	sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
     err_out:
    	sysfs_remove_group(&dev->kobj, &pm_attr_group);
    	return rc;
    }
    
    int wakeup_sysfs_add(struct device *dev)
    {
    	return sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
    }
    
    void wakeup_sysfs_remove(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
    }
    
    int pm_qos_sysfs_add_resume_latency(struct device *dev)
    {
    	return sysfs_merge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
    }
    
    void pm_qos_sysfs_remove_resume_latency(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
    }
    
    int pm_qos_sysfs_add_flags(struct device *dev)
    {
    	return sysfs_merge_group(&dev->kobj, &pm_qos_flags_attr_group);
    }
    
    void pm_qos_sysfs_remove_flags(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_qos_flags_attr_group);
    }
    
    int pm_qos_sysfs_add_latency_tolerance(struct device *dev)
    {
    	return sysfs_merge_group(&dev->kobj,
    				 &pm_qos_latency_tolerance_attr_group);
    }
    
    void pm_qos_sysfs_remove_latency_tolerance(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
    }
    
    void rpm_sysfs_remove(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
    }
    
    void dpm_sysfs_remove(struct device *dev)
    {
    	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
    	dev_pm_qos_constraints_destroy(dev);
    	rpm_sysfs_remove(dev);
    	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
    	sysfs_remove_group(&dev->kobj, &pm_attr_group);
    }