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