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1 : : // SPDX-License-Identifier: GPL-2.0 2 : : /* 3 : : * drivers/base/power/common.c - Common device power management code. 4 : : * 5 : : * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp. 6 : : */ 7 : : #include <linux/kernel.h> 8 : : #include <linux/device.h> 9 : : #include <linux/export.h> 10 : : #include <linux/slab.h> 11 : : #include <linux/pm_clock.h> 12 : : #include <linux/acpi.h> 13 : : #include <linux/pm_domain.h> 14 : : 15 : : #include "power.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 : 0 : int dev_pm_get_subsys_data(struct device *dev) 26 : : { 27 : 0 : struct pm_subsys_data *psd; 28 : : 29 : 0 : psd = kzalloc(sizeof(*psd), GFP_KERNEL); 30 [ # # ]: 0 : if (!psd) 31 : : return -ENOMEM; 32 : : 33 : 0 : spin_lock_irq(&dev->power.lock); 34 : : 35 [ # # ]: 0 : if (dev->power.subsys_data) { 36 : 0 : dev->power.subsys_data->refcount++; 37 : : } else { 38 : 0 : spin_lock_init(&psd->lock); 39 : 0 : psd->refcount = 1; 40 : 0 : dev->power.subsys_data = psd; 41 : 0 : pm_clk_init(dev); 42 : 0 : psd = NULL; 43 : : } 44 : : 45 : 0 : spin_unlock_irq(&dev->power.lock); 46 : : 47 : : /* kfree() verifies that its argument is nonzero. */ 48 : 0 : kfree(psd); 49 : : 50 : 0 : 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 : 0 : void dev_pm_put_subsys_data(struct device *dev) 62 : : { 63 : 0 : struct pm_subsys_data *psd; 64 : : 65 : 0 : spin_lock_irq(&dev->power.lock); 66 : : 67 [ # # ]: 0 : psd = dev_to_psd(dev); 68 [ # # ]: 0 : if (!psd) 69 : 0 : goto out; 70 : : 71 [ # # ]: 0 : if (--psd->refcount == 0) 72 : 0 : dev->power.subsys_data = NULL; 73 : : else 74 : : psd = NULL; 75 : : 76 : 0 : out: 77 : 0 : spin_unlock_irq(&dev->power.lock); 78 : 0 : kfree(psd); 79 : 0 : } 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 when it is found that the 100 : : * device doesn't need a PM domain, else a negative error code. 101 : : */ 102 : 90 : int dev_pm_domain_attach(struct device *dev, bool power_on) 103 : : { 104 : 90 : int ret; 105 : : 106 [ + - ]: 90 : if (dev->pm_domain) 107 : : return 0; 108 : : 109 : 90 : ret = acpi_dev_pm_attach(dev, power_on); 110 [ + - ]: 90 : if (!ret) 111 : 90 : ret = genpd_dev_pm_attach(dev); 112 : : 113 : 90 : return ret < 0 ? ret : 0; 114 : : } 115 : : EXPORT_SYMBOL_GPL(dev_pm_domain_attach); 116 : : 117 : : /** 118 : : * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains. 119 : : * @dev: The device used to lookup the PM domain. 120 : : * @index: The index of the PM domain. 121 : : * 122 : : * As @dev may only be attached to a single PM domain, the backend PM domain 123 : : * provider creates a virtual device to attach instead. If attachment succeeds, 124 : : * the ->detach() callback in the struct dev_pm_domain are assigned by the 125 : : * corresponding backend attach function, as to deal with detaching of the 126 : : * created virtual device. 127 : : * 128 : : * This function should typically be invoked by a driver during the probe phase, 129 : : * in case its device requires power management through multiple PM domains. The 130 : : * driver may benefit from using the received device, to configure device-links 131 : : * towards its original device. Depending on the use-case and if needed, the 132 : : * links may be dynamically changed by the driver, which allows it to control 133 : : * the power to the PM domains independently from each other. 134 : : * 135 : : * Callers must ensure proper synchronization of this function with power 136 : : * management callbacks. 137 : : * 138 : : * Returns the virtual created device when successfully attached to its PM 139 : : * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR(). 140 : : * Note that, to detach the returned virtual device, the driver shall call 141 : : * dev_pm_domain_detach() on it, typically during the remove phase. 142 : : */ 143 : 0 : struct device *dev_pm_domain_attach_by_id(struct device *dev, 144 : : unsigned int index) 145 : : { 146 [ # # ]: 0 : if (dev->pm_domain) 147 : 0 : return ERR_PTR(-EEXIST); 148 : : 149 : : return genpd_dev_pm_attach_by_id(dev, index); 150 : : } 151 : : EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id); 152 : : 153 : : /** 154 : : * dev_pm_domain_attach_by_name - Associate a device with one of its PM domains. 155 : : * @dev: The device used to lookup the PM domain. 156 : : * @name: The name of the PM domain. 157 : : * 158 : : * For a detailed function description, see dev_pm_domain_attach_by_id(). 159 : : */ 160 : 0 : struct device *dev_pm_domain_attach_by_name(struct device *dev, 161 : : const char *name) 162 : : { 163 [ # # ]: 0 : if (dev->pm_domain) 164 : 0 : return ERR_PTR(-EEXIST); 165 : : 166 : : return genpd_dev_pm_attach_by_name(dev, name); 167 : : } 168 : : EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_name); 169 : : 170 : : /** 171 : : * dev_pm_domain_detach - Detach a device from its PM domain. 172 : : * @dev: Device to detach. 173 : : * @power_off: Used to indicate whether we should power off the device. 174 : : * 175 : : * This functions will reverse the actions from dev_pm_domain_attach() and 176 : : * dev_pm_domain_attach_by_id(), thus it detaches @dev from its PM domain. 177 : : * Typically it should be invoked during the remove phase, either from 178 : : * subsystem level code or from drivers. 179 : : * 180 : : * Callers must ensure proper synchronization of this function with power 181 : : * management callbacks. 182 : : */ 183 : 0 : void dev_pm_domain_detach(struct device *dev, bool power_off) 184 : : { 185 [ # # # # ]: 0 : if (dev->pm_domain && dev->pm_domain->detach) 186 : 0 : dev->pm_domain->detach(dev, power_off); 187 : 0 : } 188 : : EXPORT_SYMBOL_GPL(dev_pm_domain_detach); 189 : : 190 : : /** 191 : : * dev_pm_domain_start - Start the device through its PM domain. 192 : : * @dev: Device to start. 193 : : * 194 : : * This function should typically be called during probe by a subsystem/driver, 195 : : * when it needs to start its device from the PM domain's perspective. Note 196 : : * that, it's assumed that the PM domain is already powered on when this 197 : : * function is called. 198 : : * 199 : : * Returns 0 on success and negative error values on failures. 200 : : */ 201 : 0 : int dev_pm_domain_start(struct device *dev) 202 : : { 203 [ # # # # ]: 0 : if (dev->pm_domain && dev->pm_domain->start) 204 : 0 : return dev->pm_domain->start(dev); 205 : : 206 : : return 0; 207 : : } 208 : : EXPORT_SYMBOL_GPL(dev_pm_domain_start); 209 : : 210 : : /** 211 : : * dev_pm_domain_set - Set PM domain of a device. 212 : : * @dev: Device whose PM domain is to be set. 213 : : * @pd: PM domain to be set, or NULL. 214 : : * 215 : : * Sets the PM domain the device belongs to. The PM domain of a device needs 216 : : * to be set before its probe finishes (it's bound to a driver). 217 : : * 218 : : * This function must be called with the device lock held. 219 : : */ 220 : 0 : void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) 221 : : { 222 [ # # ]: 0 : if (dev->pm_domain == pd) 223 : : return; 224 : : 225 [ # # # # : 0 : WARN(pd && device_is_bound(dev), # # ] 226 : : "PM domains can only be changed for unbound devices\n"); 227 : 0 : dev->pm_domain = pd; 228 : 0 : device_pm_check_callbacks(dev); 229 : : } 230 : : EXPORT_SYMBOL_GPL(dev_pm_domain_set);