1 /* 2 * drivers/base/power/common.c - Common device power management code. 3 * 4 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. 5 * 6 * This file is released under the GPLv2. 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/device.h> 11 #include <linux/export.h> 12 #include <linux/slab.h> 13 #include <linux/pm_clock.h> 14 #include <linux/acpi.h> 15 #include <linux/pm_domain.h> 16 17 /** 18 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device. 19 * @dev: Device to handle. 20 * 21 * If power.subsys_data is NULL, point it to a new object, otherwise increment 22 * its reference counter. Return 0 if new object has been created or refcount 23 * increased, otherwise negative error code. 24 */ 25 int dev_pm_get_subsys_data(struct device *dev) 26 { 27 struct pm_subsys_data *psd; 28 29 psd = kzalloc(sizeof(*psd), GFP_KERNEL); 30 if (!psd) 31 return -ENOMEM; 32 33 spin_lock_irq(&dev->power.lock); 34 35 if (dev->power.subsys_data) { 36 dev->power.subsys_data->refcount++; 37 } else { 38 spin_lock_init(&psd->lock); 39 psd->refcount = 1; 40 dev->power.subsys_data = psd; 41 pm_clk_init(dev); 42 psd = NULL; 43 } 44 45 spin_unlock_irq(&dev->power.lock); 46 47 /* kfree() verifies that its argument is nonzero. */ 48 kfree(psd); 49 50 return 0; 51 } 52 EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data); 53 54 /** 55 * dev_pm_put_subsys_data - Drop reference to power.subsys_data. 56 * @dev: Device to handle. 57 * 58 * If the reference counter of power.subsys_data is zero after dropping the 59 * reference, power.subsys_data is removed. 60 */ 61 void dev_pm_put_subsys_data(struct device *dev) 62 { 63 struct pm_subsys_data *psd; 64 65 spin_lock_irq(&dev->power.lock); 66 67 psd = dev_to_psd(dev); 68 if (!psd) 69 goto out; 70 71 if (--psd->refcount == 0) 72 dev->power.subsys_data = NULL; 73 else 74 psd = NULL; 75 76 out: 77 spin_unlock_irq(&dev->power.lock); 78 kfree(psd); 79 } 80 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); 81 82 /** 83 * dev_pm_domain_attach - Attach a device to its PM domain. 84 * @dev: Device to attach. 85 * @power_on: Used to indicate whether we should power on the device. 86 * 87 * The @dev may only be attached to a single PM domain. By iterating through 88 * the available alternatives we try to find a valid PM domain for the device. 89 * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain 90 * should be assigned by the corresponding attach function. 91 * 92 * This function should typically be invoked from subsystem level code during 93 * the probe phase. Especially for those that holds devices which requires 94 * power management through PM domains. 95 * 96 * Callers must ensure proper synchronization of this function with power 97 * management callbacks. 98 * 99 * Returns 0 on successfully attached PM domain or negative error code. 100 */ 101 int dev_pm_domain_attach(struct device *dev, bool power_on) 102 { 103 int ret; 104 105 ret = acpi_dev_pm_attach(dev, power_on); 106 if (ret) 107 ret = genpd_dev_pm_attach(dev); 108 109 return ret; 110 } 111 EXPORT_SYMBOL_GPL(dev_pm_domain_attach); 112 113 /** 114 * dev_pm_domain_detach - Detach a device from its PM domain. 115 * @dev: Device to attach. 116 * @power_off: Used to indicate whether we should power off the device. 117 * 118 * This functions will reverse the actions from dev_pm_domain_attach() and thus 119 * try to detach the @dev from its PM domain. Typically it should be invoked 120 * from subsystem level code during the remove phase. 121 * 122 * Callers must ensure proper synchronization of this function with power 123 * management callbacks. 124 */ 125 void dev_pm_domain_detach(struct device *dev, bool power_off) 126 { 127 if (dev->pm_domain && dev->pm_domain->detach) 128 dev->pm_domain->detach(dev, power_off); 129 } 130 EXPORT_SYMBOL_GPL(dev_pm_domain_detach); 131