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 */ 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 */ 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 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 } 117 118 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 } 129 130 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