drivers/extcon/devres.c

   1 /*
   2  *  drivers/extcon/devres.c - EXTCON device's resource management
   3  *
   4  * Copyright (C) 2016 Samsung Electronics
   5  * Author: Chanwoo Choi <cw00.choi@samsung.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/extcon.h>
  18
  19 static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
  20 {
  21         struct extcon_dev **r = res;
  22
  23         if (WARN_ON(!r || !*r))
  24                 return 0;
  25
  26         return *r == data;
  27 }
  28
  29 static void devm_extcon_dev_release(struct device *dev, void *res)
  30 {
  31         extcon_dev_free(*(struct extcon_dev **)res);
  32 }
  33
  34
  35 static void devm_extcon_dev_unreg(struct device *dev, void *res)
  36 {
  37         extcon_dev_unregister(*(struct extcon_dev **)res);
  38 }
  39
  40 /**
  41  * devm_extcon_dev_allocate - Allocate managed extcon device
  42  * @dev:                device owning the extcon device being created
  43  * @supported_cable:    Array of supported extcon ending with EXTCON_NONE.
  44  *                      If supported_cable is NULL, cable name related APIs
  45  *                      are disabled.
  46  *
  47  * This function manages automatically the memory of extcon device using device
  48  * resource management and simplify the control of freeing the memory of extcon
  49  * device.
  50  *
  51  * Returns the pointer memory of allocated extcon_dev if success
  52  * or ERR_PTR(err) if fail
  53  */
  54 struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
  55                                         const unsigned int *supported_cable)
  56 {
  57         struct extcon_dev **ptr, *edev;
  58
  59         ptr = devres_alloc(devm_extcon_dev_release, sizeof(*ptr), GFP_KERNEL);
  60         if (!ptr)
  61                 return ERR_PTR(-ENOMEM);
  62
  63         edev = extcon_dev_allocate(supported_cable);
  64         if (IS_ERR(edev)) {
  65                 devres_free(ptr);
  66                 return edev;
  67         }
  68
  69         edev->dev.parent = dev;
  70
  71         *ptr = edev;
  72         devres_add(dev, ptr);
  73
  74         return edev;
  75 }
  76 EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);
  77
  78 /**
  79  * devm_extcon_dev_free() - Resource-managed extcon_dev_unregister()
  80  * @dev:        device the extcon belongs to
  81  * @edev:       the extcon device to unregister
  82  *
  83  * Free the memory that is allocated with devm_extcon_dev_allocate()
  84  * function.
  85  */
  86 void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev)
  87 {
  88         WARN_ON(devres_release(dev, devm_extcon_dev_release,
  89                                devm_extcon_dev_match, edev));
  90 }
  91 EXPORT_SYMBOL_GPL(devm_extcon_dev_free);
  92
  93 /**
  94  * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
  95  * @dev:        device to allocate extcon device
  96  * @edev:       the new extcon device to register
  97  *
  98  * Managed extcon_dev_register() function. If extcon device is attached with
  99  * this function, that extcon device is automatically unregistered on driver
 100  * detach. Internally this function calls extcon_dev_register() function.
 101  * To get more information, refer that function.
 102  *
 103  * If extcon device is registered with this function and the device needs to be
 104  * unregistered separately, devm_extcon_dev_unregister() should be used.
 105  *
 106  * Returns 0 if success or negaive error number if failure.
 107  */
 108 int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
 109 {
 110         struct extcon_dev **ptr;
 111         int ret;
 112
 113         ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
 114         if (!ptr)
 115                 return -ENOMEM;
 116
 117         ret = extcon_dev_register(edev);
 118         if (ret) {
 119                 devres_free(ptr);
 120                 return ret;
 121         }
 122
 123         *ptr = edev;
 124         devres_add(dev, ptr);
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
 129
 130 /**
 131  * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
 132  * @dev:        device the extcon belongs to
 133  * @edev:       the extcon device to unregister
 134  *
 135  * Unregister extcon device that is registered with devm_extcon_dev_register()
 136  * function.
 137  */
 138 void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
 139 {
 140         WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
 141                                devm_extcon_dev_match, edev));
 142 }
 143 EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);