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/init.h> 10 #include <linux/kernel.h> 11 #include <linux/device.h> 12 #include <linux/export.h> 13 #include <linux/slab.h> 14 #include <linux/pm_clock.h> 15 16 /** 17 * dev_pm_get_subsys_data - Create or refcount power.subsys_data for device. 18 * @dev: Device to handle. 19 * 20 * If power.subsys_data is NULL, point it to a new object, otherwise increment 21 * its reference counter. Return 1 if a new object has been created, otherwise 22 * return 0 or error code. 23 */ 24 int dev_pm_get_subsys_data(struct device *dev) 25 { 26 struct pm_subsys_data *psd; 27 28 psd = kzalloc(sizeof(*psd), GFP_KERNEL); 29 if (!psd) 30 return -ENOMEM; 31 32 spin_lock_irq(&dev->power.lock); 33 34 if (dev->power.subsys_data) { 35 dev->power.subsys_data->refcount++; 36 } else { 37 spin_lock_init(&psd->lock); 38 psd->refcount = 1; 39 dev->power.subsys_data = psd; 40 pm_clk_init(dev); 41 psd = NULL; 42 } 43 44 spin_unlock_irq(&dev->power.lock); 45 46 /* kfree() verifies that its argument is nonzero. */ 47 kfree(psd); 48 49 return 0; 50 } 51 EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data); 52 53 /** 54 * dev_pm_put_subsys_data - Drop reference to power.subsys_data. 55 * @dev: Device to handle. 56 * 57 * If the reference counter of power.subsys_data is zero after dropping the 58 * reference, power.subsys_data is removed. Return 1 if that happens or 0 59 * otherwise. 60 */ 61 int dev_pm_put_subsys_data(struct device *dev) 62 { 63 struct pm_subsys_data *psd; 64 int ret = 0; 65 66 spin_lock_irq(&dev->power.lock); 67 68 psd = dev_to_psd(dev); 69 if (!psd) { 70 ret = -EINVAL; 71 goto out; 72 } 73 74 if (--psd->refcount == 0) { 75 dev->power.subsys_data = NULL; 76 kfree(psd); 77 ret = 1; 78 } 79 80 out: 81 spin_unlock_irq(&dev->power.lock); 82 83 return ret; 84 } 85 EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data); 86