aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/hwmon.c
blob: a61e7815a2a9153f7ad82e8dc2ff49273763c19a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
/*
    hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring

    This file defines the sysfs class "hwmon", for use by sensors drivers.

    Copyright (C) 2005 Mark M. Hoffman <mhoffman@lightlink.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; version 2 of the License.
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/hwmon.h>
#include <linux/gfp.h>
#include <linux/spinlock.h>
#include <linux/pci.h>

#define HWMON_ID_PREFIX "hwmon"
#define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"

static struct class *hwmon_class;

static DEFINE_IDR(hwmon_idr);
static DEFINE_SPINLOCK(idr_lock);

/**
 * hwmon_device_register - register w/ hwmon
 * @dev: the device to register
 *
 * hwmon_device_unregister() must be called when the device is no
 * longer needed.
 *
 * Returns the pointer to the new device.
 */
struct device *hwmon_device_register(struct device *dev)
{
	struct device *hwdev;
	int id, err;

again:
	if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
		return ERR_PTR(-ENOMEM);

	spin_lock(&idr_lock);
	err = idr_get_new(&hwmon_idr, NULL, &id);
	spin_unlock(&idr_lock);

	if (unlikely(err == -EAGAIN))
		goto again;
	else if (unlikely(err))
		return ERR_PTR(err);

	id = id & MAX_ID_MASK;
	hwdev = device_create(hwmon_class, dev, MKDEV(0, 0), NULL,
			      HWMON_ID_FORMAT, id);

	if (IS_ERR(hwdev)) {
		spin_lock(&idr_lock);
		idr_remove(&hwmon_idr, id);
		spin_unlock(&idr_lock);
	}

	return hwdev;
}

/**
 * hwmon_device_unregister - removes the previously registered class device
 *
 * @dev: the class device to destroy
 */
void hwmon_device_unregister(struct device *dev)
{
	int id;

	if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
		device_unregister(dev);
		spin_lock(&idr_lock);
		idr_remove(&hwmon_idr, id);
		spin_unlock(&idr_lock);
	} else
		dev_dbg(dev->parent,
			"hwmon_device_unregister() failed: bad class ID!\n");
}

static void __init hwmon_pci_quirks(void)
{
#if defined CONFIG_X86 && defined CONFIG_PCI
	struct pci_dev *sb;
	u16 base;
	u8 enable;

	/* Open access to 0x295-0x296 on MSI MS-7031 */
	sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
	if (sb &&
	    (sb->subsystem_vendor == 0x1462 &&	/* MSI */
	     sb->subsystem_device == 0x0031)) {	/* MS-7031 */

		pci_read_config_byte(sb, 0x48, &enable);
		pci_read_config_word(sb, 0x64, &base);

		if (base == 0 && !(enable & BIT(2))) {
			dev_info(&sb->dev,
				 "Opening wide generic port at 0x295\n");
			pci_write_config_word(sb, 0x64, 0x295);
			pci_write_config_byte(sb, 0x48, enable | BIT(2));
		}
	}
#endif
}

static int __init hwmon_init(void)
{
	hwmon_pci_quirks();

	hwmon_class = class_create(THIS_MODULE, "hwmon");
	if (IS_ERR(hwmon_class)) {
		pr_err("couldn't create sysfs class\n");
		return PTR_ERR(hwmon_class);
	}
	return 0;
}

static void __exit hwmon_exit(void)
{
	class_destroy(hwmon_class);
}

subsys_initcall(hwmon_init);
module_exit(hwmon_exit);

EXPORT_SYMBOL_GPL(hwmon_device_register);
EXPORT_SYMBOL_GPL(hwmon_device_unregister);

MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
MODULE_LICENSE("GPL");