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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/module.h>
16 #include <linux/device.h>
17 #include <linux/err.h>
18 #include <linux/kdev_t.h>
19 #include <linux/idr.h>
20 #include <linux/hwmon.h>
21 #include <linux/gfp.h>
22 #include <linux/spinlock.h>
23 #include <linux/pci.h>
24
25 #define HWMON_ID_PREFIX "hwmon"
26 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"
27
28 static struct class *hwmon_class;
29
30 static DEFINE_IDR(hwmon_idr);
31 static DEFINE_SPINLOCK(idr_lock);
32
33 /**
34 * hwmon_device_register - register w/ hwmon
35 * @dev: the device to register
36 *
37 * hwmon_device_unregister() must be called when the device is no
38 * longer needed.
39 *
40 * Returns the pointer to the new device.
41 */
hwmon_device_register(struct device * dev)42 struct device *hwmon_device_register(struct device *dev)
43 {
44 struct device *hwdev;
45 int id, err;
46
47 again:
48 if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0))
49 return ERR_PTR(-ENOMEM);
50
51 spin_lock(&idr_lock);
52 err = idr_get_new(&hwmon_idr, NULL, &id);
53 spin_unlock(&idr_lock);
54
55 if (unlikely(err == -EAGAIN))
56 goto again;
57 else if (unlikely(err))
58 return ERR_PTR(err);
59
60 id = id & MAX_ID_MASK;
61 hwdev = device_create(hwmon_class, dev, MKDEV(0, 0), NULL,
62 HWMON_ID_FORMAT, id);
63
64 if (IS_ERR(hwdev)) {
65 spin_lock(&idr_lock);
66 idr_remove(&hwmon_idr, id);
67 spin_unlock(&idr_lock);
68 }
69
70 return hwdev;
71 }
72
73 /**
74 * hwmon_device_unregister - removes the previously registered class device
75 *
76 * @dev: the class device to destroy
77 */
hwmon_device_unregister(struct device * dev)78 void hwmon_device_unregister(struct device *dev)
79 {
80 int id;
81
82 if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
83 device_unregister(dev);
84 spin_lock(&idr_lock);
85 idr_remove(&hwmon_idr, id);
86 spin_unlock(&idr_lock);
87 } else
88 dev_dbg(dev->parent,
89 "hwmon_device_unregister() failed: bad class ID!\n");
90 }
91
hwmon_pci_quirks(void)92 static void __init hwmon_pci_quirks(void)
93 {
94 #if defined CONFIG_X86 && defined CONFIG_PCI
95 struct pci_dev *sb;
96 u16 base;
97 u8 enable;
98
99 /* Open access to 0x295-0x296 on MSI MS-7031 */
100 sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
101 if (sb &&
102 (sb->subsystem_vendor == 0x1462 && /* MSI */
103 sb->subsystem_device == 0x0031)) { /* MS-7031 */
104
105 pci_read_config_byte(sb, 0x48, &enable);
106 pci_read_config_word(sb, 0x64, &base);
107
108 if (base == 0 && !(enable & BIT(2))) {
109 dev_info(&sb->dev,
110 "Opening wide generic port at 0x295\n");
111 pci_write_config_word(sb, 0x64, 0x295);
112 pci_write_config_byte(sb, 0x48, enable | BIT(2));
113 }
114 }
115 #endif
116 }
117
hwmon_init(void)118 static int __init hwmon_init(void)
119 {
120 hwmon_pci_quirks();
121
122 hwmon_class = class_create(THIS_MODULE, "hwmon");
123 if (IS_ERR(hwmon_class)) {
124 pr_err("couldn't create sysfs class\n");
125 return PTR_ERR(hwmon_class);
126 }
127 return 0;
128 }
129
hwmon_exit(void)130 static void __exit hwmon_exit(void)
131 {
132 class_destroy(hwmon_class);
133 }
134
135 subsys_initcall(hwmon_init);
136 module_exit(hwmon_exit);
137
138 EXPORT_SYMBOL_GPL(hwmon_device_register);
139 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
140
141 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
142 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
143 MODULE_LICENSE("GPL");
144
145