1 /* 2 * drivers/base/power/main.c - Where the driver meets power management. 3 * 4 * Copyright (c) 2003 Patrick Mochel 5 * Copyright (c) 2003 Open Source Development Lab 6 * 7 * This file is released under the GPLv2 8 * 9 * 10 * The driver model core calls device_pm_add() when a device is registered. 11 * This will intialize the embedded device_pm_info object in the device 12 * and add it to the list of power-controlled devices. sysfs entries for 13 * controlling device power management will also be added. 14 * 15 * A different set of lists than the global subsystem list are used to 16 * keep track of power info because we use different lists to hold 17 * devices based on what stage of the power management process they 18 * are in. The power domain dependencies may also differ from the 19 * ancestral dependencies that the subsystem list maintains. 20 */ 21 22 #include <linux/config.h> 23 #include <linux/device.h> 24 #include "power.h" 25 26 LIST_HEAD(dpm_active); 27 LIST_HEAD(dpm_off); 28 LIST_HEAD(dpm_off_irq); 29 30 DECLARE_MUTEX(dpm_sem); 31 DECLARE_MUTEX(dpm_list_sem); 32 33 /** 34 * device_pm_set_parent - Specify power dependency. 35 * @dev: Device who needs power. 36 * @parent: Device that supplies power. 37 * 38 * This function is used to manually describe a power-dependency 39 * relationship. It may be used to specify a transversal relationship 40 * (where the power supplier is not the physical (or electrical) 41 * ancestor of a specific device. 42 * The effect of this is that the supplier will not be powered down 43 * before the power dependent. 44 */ 45 46 void device_pm_set_parent(struct device * dev, struct device * parent) 47 { 48 put_device(dev->power.pm_parent); 49 dev->power.pm_parent = get_device(parent); 50 } 51 EXPORT_SYMBOL_GPL(device_pm_set_parent); 52 53 int device_pm_add(struct device * dev) 54 { 55 int error; 56 57 pr_debug("PM: Adding info for %s:%s\n", 58 dev->bus ? dev->bus->name : "No Bus", dev->kobj.name); 59 down(&dpm_list_sem); 60 list_add_tail(&dev->power.entry, &dpm_active); 61 device_pm_set_parent(dev, dev->parent); 62 if ((error = dpm_sysfs_add(dev))) 63 list_del(&dev->power.entry); 64 up(&dpm_list_sem); 65 return error; 66 } 67 68 void device_pm_remove(struct device * dev) 69 { 70 pr_debug("PM: Removing info for %s:%s\n", 71 dev->bus ? dev->bus->name : "No Bus", dev->kobj.name); 72 down(&dpm_list_sem); 73 dpm_sysfs_remove(dev); 74 put_device(dev->power.pm_parent); 75 list_del_init(&dev->power.entry); 76 up(&dpm_list_sem); 77 } 78 79 80