1 files changed, 99 insertions, 0 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
new file mode 100644
index 000000000000..15e6a8f951f1
--- /dev/null
+++ b/drivers/base/power/main.c
@@ -0,0 +1,99 @@
+/*
+ * drivers/base/power/main.c - Where the driver meets power management.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ *
+ * This file is released under the GPLv2
+ *
+ *
+ * The driver model core calls device_pm_add() when a device is registered.
+ * This will intialize the embedded device_pm_info object in the device
+ * and add it to the list of power-controlled devices. sysfs entries for
+ * controlling device power management will also be added.
+ *
+ * A different set of lists than the global subsystem list are used to
+ * keep track of power info because we use different lists to hold
+ * devices based on what stage of the power management process they
+ * are in. The power domain dependencies may also differ from the
+ * ancestral dependencies that the subsystem list maintains.
+ */
+
+#include <linux/config.h>
+#include <linux/device.h>
+#include "power.h"
+
+LIST_HEAD(dpm_active);
+LIST_HEAD(dpm_off);
+LIST_HEAD(dpm_off_irq);
+
+DECLARE_MUTEX(dpm_sem);
+DECLARE_MUTEX(dpm_list_sem);
+
+/*
+ * PM Reference Counting.
+ */
+
+static inline void device_pm_hold(struct device * dev)
+{
+        if (dev)
+                atomic_inc(&dev->power.pm_users);
+}
+
+static inline void device_pm_release(struct device * dev)
+{
+        if (dev)
+                atomic_dec(&dev->power.pm_users);
+}
+
+
+/**
+ *      device_pm_set_parent - Specify power dependency.
+ *      @dev:           Device who needs power.
+ *      @parent:        Device that supplies power.
+ *
+ *      This function is used to manually describe a power-dependency
+ *      relationship. It may be used to specify a transversal relationship
+ *      (where the power supplier is not the physical (or electrical)
+ *      ancestor of a specific device.
+ *      The effect of this is that the supplier will not be powered down
+ *      before the power dependent.
+ */
+
+void device_pm_set_parent(struct device * dev, struct device * parent)
+{
+        struct device * old_parent = dev->power.pm_parent;
+        device_pm_release(old_parent);
+        dev->power.pm_parent = parent;
+        device_pm_hold(parent);
+}
+EXPORT_SYMBOL_GPL(device_pm_set_parent);
+
+int device_pm_add(struct device * dev)
+{
+        int error;
+
+        pr_debug("PM: Adding info for %s:%s\n",
+                 dev->bus ? dev->bus->name : "No Bus", dev->kobj.name);
+        atomic_set(&dev->power.pm_users, 0);
+        down(&dpm_list_sem);
+        list_add_tail(&dev->power.entry, &dpm_active);
+        device_pm_set_parent(dev, dev->parent);
+        if ((error = dpm_sysfs_add(dev)))
+                list_del(&dev->power.entry);
+        up(&dpm_list_sem);
+        return error;
+}
+
+void device_pm_remove(struct device * dev)
+{
+        pr_debug("PM: Removing info for %s:%s\n",
+                 dev->bus ? dev->bus->name : "No Bus", dev->kobj.name);
+        down(&dpm_list_sem);
+        dpm_sysfs_remove(dev);
+        device_pm_release(dev->power.pm_parent);
+        list_del_init(&dev->power.entry);
+        up(&dpm_list_sem);
+}
+
+