1 files changed, 68 insertions, 0 deletions
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
new file mode 100644
index 00000000000..6ac96349a8e
--- /dev/null
+++ b/drivers/base/power/sysfs.c
@@ -0,0 +1,68 @@
+/*
+ * drivers/base/power/sysfs.c - sysfs entries for device PM
+ */
+
+#include <linux/device.h>
+#include "power.h"
+
+
+/**
+ *	state - Control current power state of device
+ *
+ *	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.
+ *
+ *	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.
+ */
+
+static ssize_t state_show(struct device * dev, char * buf)
+{
+	return sprintf(buf, "%u\n", dev->power.power_state);
+}
+
+static ssize_t state_store(struct device * dev, const char * buf, size_t n)
+{
+	u32 state;
+	char * rest;
+	int error = 0;
+
+	state = simple_strtoul(buf, &rest, 10);
+	if (*rest)
+		return -EINVAL;
+	if (state)
+		error = dpm_runtime_suspend(dev, state);
+	else
+		dpm_runtime_resume(dev);
+	return error ? error : n;
+}
+
+static DEVICE_ATTR(state, 0644, state_show, state_store);
+
+
+static struct attribute * power_attrs[] = {
+	&dev_attr_state.attr,
+	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);
+}