| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
|---|---|
| 2 | |
| 3 | /* Firmware attributes class helper module */ |
| 4 | |
| 5 | #include <linux/mutex.h> |
| 6 | #include <linux/device/class.h> |
| 7 | #include <linux/module.h> |
| 8 | #include "firmware_attributes_class.h" |
| 9 | |
| 10 | static DEFINE_MUTEX(fw_attr_lock); |
| 11 | static int fw_attr_inuse; |
| 12 | |
| 13 | static const struct class firmware_attributes_class = { |
| 14 | .name = "firmware-attributes", |
| 15 | }; |
| 16 | |
| 17 | int fw_attributes_class_get(const struct class **fw_attr_class) |
| 18 | { |
| 19 | int err; |
| 20 | |
| 21 | mutex_lock(&fw_attr_lock); |
| 22 | if (!fw_attr_inuse) { /*first time class is being used*/ |
| 23 | err = class_register(class: &firmware_attributes_class); |
| 24 | if (err) { |
| 25 | mutex_unlock(lock: &fw_attr_lock); |
| 26 | return err; |
| 27 | } |
| 28 | } |
| 29 | fw_attr_inuse++; |
| 30 | *fw_attr_class = &firmware_attributes_class; |
| 31 | mutex_unlock(lock: &fw_attr_lock); |
| 32 | return 0; |
| 33 | } |
| 34 | EXPORT_SYMBOL_GPL(fw_attributes_class_get); |
| 35 | |
| 36 | int fw_attributes_class_put(void) |
| 37 | { |
| 38 | mutex_lock(&fw_attr_lock); |
| 39 | if (!fw_attr_inuse) { |
| 40 | mutex_unlock(lock: &fw_attr_lock); |
| 41 | return -EINVAL; |
| 42 | } |
| 43 | fw_attr_inuse--; |
| 44 | if (!fw_attr_inuse) /* No more consumers */ |
| 45 | class_unregister(class: &firmware_attributes_class); |
| 46 | mutex_unlock(lock: &fw_attr_lock); |
| 47 | return 0; |
| 48 | } |
| 49 | EXPORT_SYMBOL_GPL(fw_attributes_class_put); |
| 50 | |
| 51 | MODULE_AUTHOR("Mark Pearson <markpearson@lenovo.com>"); |
| 52 | MODULE_LICENSE("GPL"); |
| 53 |