blob: 106fa01cdb6069717c61ee6a596e94d1ad38bf98 [file] [log] [blame]
Mark M. Hoffman12364412005-07-15 21:38:08 -04001/*
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>
Tim Schmielau8c65b4a2005-11-07 00:59:43 -080019#include <linux/gfp.h>
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010020#include <linux/spinlock.h>
Mark M. Hoffman12364412005-07-15 21:38:08 -040021
22#define HWMON_ID_PREFIX "hwmon"
23#define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
24
25static struct class *hwmon_class;
26
27static DEFINE_IDR(hwmon_idr);
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010028static DEFINE_SPINLOCK(idr_lock);
Mark M. Hoffman12364412005-07-15 21:38:08 -040029
30/**
31 * hwmon_device_register - register w/ hwmon sysfs class
32 * @dev: the device to register
33 *
34 * hwmon_device_unregister() must be called when the class device is no
35 * longer needed.
36 *
37 * Returns the pointer to the new struct class device.
38 */
39struct class_device *hwmon_device_register(struct device *dev)
40{
41 struct class_device *cdev;
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010042 int id, err;
Mark M. Hoffman12364412005-07-15 21:38:08 -040043
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010044again:
45 if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
Mark M. Hoffman12364412005-07-15 21:38:08 -040046 return ERR_PTR(-ENOMEM);
47
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010048 spin_lock(&idr_lock);
49 err = idr_get_new(&hwmon_idr, NULL, &id);
50 spin_unlock(&idr_lock);
51
52 if (unlikely(err == -EAGAIN))
53 goto again;
54 else if (unlikely(err))
55 return ERR_PTR(err);
Mark M. Hoffman12364412005-07-15 21:38:08 -040056
57 id = id & MAX_ID_MASK;
Greg Kroah-Hartman53f46542005-10-27 22:25:43 -070058 cdev = class_device_create(hwmon_class, NULL, MKDEV(0,0), dev,
Mark M. Hoffman12364412005-07-15 21:38:08 -040059 HWMON_ID_FORMAT, id);
60
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010061 if (IS_ERR(cdev)) {
62 spin_lock(&idr_lock);
Mark M. Hoffman12364412005-07-15 21:38:08 -040063 idr_remove(&hwmon_idr, id);
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010064 spin_unlock(&idr_lock);
65 }
Mark M. Hoffman12364412005-07-15 21:38:08 -040066
67 return cdev;
68}
69
70/**
71 * hwmon_device_unregister - removes the previously registered class device
72 *
73 * @cdev: the class device to destroy
74 */
75void hwmon_device_unregister(struct class_device *cdev)
76{
77 int id;
78
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010079 if (likely(sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1)) {
Mark M. Hoffman12364412005-07-15 21:38:08 -040080 class_device_unregister(cdev);
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010081 spin_lock(&idr_lock);
Mark M. Hoffman12364412005-07-15 21:38:08 -040082 idr_remove(&hwmon_idr, id);
Mark M. Hoffmanded2b662006-03-05 23:13:47 +010083 spin_unlock(&idr_lock);
Mark M. Hoffman12364412005-07-15 21:38:08 -040084 } else
85 dev_dbg(cdev->dev,
86 "hwmon_device_unregister() failed: bad class ID!\n");
87}
88
89static int __init hwmon_init(void)
90{
91 hwmon_class = class_create(THIS_MODULE, "hwmon");
92 if (IS_ERR(hwmon_class)) {
93 printk(KERN_ERR "hwmon.c: couldn't create sysfs class\n");
94 return PTR_ERR(hwmon_class);
95 }
96 return 0;
97}
98
99static void __exit hwmon_exit(void)
100{
101 class_destroy(hwmon_class);
102}
103
104module_init(hwmon_init);
105module_exit(hwmon_exit);
106
107EXPORT_SYMBOL_GPL(hwmon_device_register);
108EXPORT_SYMBOL_GPL(hwmon_device_unregister);
109
110MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
111MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
112MODULE_LICENSE("GPL");
113