summaryrefslogtreecommitdiff
path: root/drivers/base/power/sysfs.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/base/power/sysfs.c')
-rw-r--r--drivers/base/power/sysfs.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 596aeecfdff..86fd9373447 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -4,9 +4,25 @@
#include <linux/device.h>
#include <linux/string.h>
+#include <linux/pm_runtime.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
@@ -38,11 +54,61 @@
* 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)
{
@@ -77,9 +143,43 @@ wake_store(struct device * dev, struct device_attribute *attr,
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 = {