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 1 if a new object has been created, otherwise 23 * return 0 or 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. Return 1 if that happens or 0 60 * otherwise. 61 */ 62 int dev_pm_put_subsys_data(struct device *dev) 63 { 64 struct pm_subsys_data *psd; 65 int ret = 1; 66 67 spin_lock_irq(&dev->power.lock); 68 69 psd = dev_to_psd(dev); 70 if (!psd) 71 goto out; 72 73 if (--psd->refcount == 0) { 74 dev->power.subsys_data = NULL; 75 } else { 76 psd = NULL; 77 ret = 0; 78 } 79 80 out: 81 spin_unlock_irq(&dev->power.lock); 82 kfree(psd); 83 84 return ret; 85 } 86 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); 87 88 /** 89 * dev_pm_domain_attach - Attach a device to its PM domain. 90 * @dev: Device to attach. 91 * @power_on: Used to indicate whether we should power on the device. 92 * 93 * The @dev may only be attached to a single PM domain. By iterating through 94 * the available alternatives we try to find a valid PM domain for the device. 95 * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain 96 * should be assigned by the corresponding attach function. 97 * 98 * This function should typically be invoked from subsystem level code during 99 * the probe phase. Especially for those that holds devices which requires 100 * power management through PM domains. 101 * 102 * Callers must ensure proper synchronization of this function with power 103 * management callbacks. 104 * 105 * Returns 0 on successfully attached PM domain or negative error code. 106 */ 107 int dev_pm_domain_attach(struct device *dev, bool power_on) 108 { 109 int ret; 110 111 ret = acpi_dev_pm_attach(dev, power_on); 112 if (ret) 113 ret = genpd_dev_pm_attach(dev); 114 115 return ret; 116 } 117 EXPORT_SYMBOL_GPL(dev_pm_domain_attach); 118 119 /** 120 * dev_pm_domain_detach - Detach a device from its PM domain. 121 * @dev: Device to attach. 122 * @power_off: Used to indicate whether we should power off the device. 123 * 124 * This functions will reverse the actions from dev_pm_domain_attach() and thus 125 * try to detach the @dev from its PM domain. Typically it should be invoked 126 * from subsystem level code during the remove phase. 127 * 128 * Callers must ensure proper synchronization of this function with power 129 * management callbacks. 130 */ 131 void dev_pm_domain_detach(struct device *dev, bool power_off) 132 { 133 if (dev->pm_domain && dev->pm_domain->detach) 134 dev->pm_domain->detach(dev, power_off); 135 } 136 EXPORT_SYMBOL_GPL(dev_pm_domain_detach); 137