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#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
  28static struct class *hwmon_class;
  29
  30static DEFINE_IDR(hwmon_idr);
  31static 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 */
  42struct device *hwmon_device_register(struct device *dev)
  43{
  44        struct device *hwdev;
  45        int id, err;
  46
  47again:
  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 */
  78void 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
  92static 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
 118static 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
 130static void __exit hwmon_exit(void)
 131{
 132        class_destroy(hwmon_class);
 133}
 134
 135subsys_initcall(hwmon_init);
 136module_exit(hwmon_exit);
 137
 138EXPORT_SYMBOL_GPL(hwmon_device_register);
 139EXPORT_SYMBOL_GPL(hwmon_device_unregister);
 140
 141MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 142MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
 143MODULE_LICENSE("GPL");
 144
 145