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1236441f MH |
1 | /* |
2 | hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring | |
3 | ||
4 | This file defines the sysfs class "hwmon", for use by sensors drivers. | |
5 | ||
6 | Copyright (C) 2005 Mark M. Hoffman <mhoffman@lightlink.com> | |
7 | ||
8 | This program is free software; you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; version 2 of the License. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/kdev_t.h> | |
17 | #include <linux/idr.h> | |
18 | #include <linux/hwmon.h> | |
19 | ||
20 | #define HWMON_ID_PREFIX "hwmon" | |
21 | #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d" | |
22 | ||
23 | static struct class *hwmon_class; | |
24 | ||
25 | static DEFINE_IDR(hwmon_idr); | |
26 | ||
27 | /** | |
28 | * hwmon_device_register - register w/ hwmon sysfs class | |
29 | * @dev: the device to register | |
30 | * | |
31 | * hwmon_device_unregister() must be called when the class device is no | |
32 | * longer needed. | |
33 | * | |
34 | * Returns the pointer to the new struct class device. | |
35 | */ | |
36 | struct class_device *hwmon_device_register(struct device *dev) | |
37 | { | |
38 | struct class_device *cdev; | |
39 | int id; | |
40 | ||
41 | if (idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0) | |
42 | return ERR_PTR(-ENOMEM); | |
43 | ||
44 | if (idr_get_new(&hwmon_idr, NULL, &id) < 0) | |
45 | return ERR_PTR(-ENOMEM); | |
46 | ||
47 | id = id & MAX_ID_MASK; | |
48 | cdev = class_device_create(hwmon_class, MKDEV(0,0), dev, | |
49 | HWMON_ID_FORMAT, id); | |
50 | ||
51 | if (IS_ERR(cdev)) | |
52 | idr_remove(&hwmon_idr, id); | |
53 | ||
54 | return cdev; | |
55 | } | |
56 | ||
57 | /** | |
58 | * hwmon_device_unregister - removes the previously registered class device | |
59 | * | |
60 | * @cdev: the class device to destroy | |
61 | */ | |
62 | void hwmon_device_unregister(struct class_device *cdev) | |
63 | { | |
64 | int id; | |
65 | ||
66 | if (sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1) { | |
67 | class_device_unregister(cdev); | |
68 | idr_remove(&hwmon_idr, id); | |
69 | } else | |
70 | dev_dbg(cdev->dev, | |
71 | "hwmon_device_unregister() failed: bad class ID!\n"); | |
72 | } | |
73 | ||
74 | static int __init hwmon_init(void) | |
75 | { | |
76 | hwmon_class = class_create(THIS_MODULE, "hwmon"); | |
77 | if (IS_ERR(hwmon_class)) { | |
78 | printk(KERN_ERR "hwmon.c: couldn't create sysfs class\n"); | |
79 | return PTR_ERR(hwmon_class); | |
80 | } | |
81 | return 0; | |
82 | } | |
83 | ||
84 | static void __exit hwmon_exit(void) | |
85 | { | |
86 | class_destroy(hwmon_class); | |
87 | } | |
88 | ||
89 | module_init(hwmon_init); | |
90 | module_exit(hwmon_exit); | |
91 | ||
92 | EXPORT_SYMBOL_GPL(hwmon_device_register); | |
93 | EXPORT_SYMBOL_GPL(hwmon_device_unregister); | |
94 | ||
95 | MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); | |
96 | MODULE_DESCRIPTION("hardware monitoring sysfs/class support"); | |
97 | MODULE_LICENSE("GPL"); | |
98 |