LXR linux/drivers/hwmon/hwmon.c

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