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