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 000000000000..6ac96349a8e8
--- /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);
+}