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
  28 static struct class *hwmon_class;
  29
  30 static 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  */
  41 struct 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 }
  58
  59 /**
  60  * hwmon_device_unregister - removes the previously registered class device
  61  *
  62  * @dev: the class device to destroy
  63  */
  64 void hwmon_device_unregister(struct device *dev)
  65 {
  66         int id;
  67
  68         if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
  69                 device_unregister(dev);
  70                 ida_simple_remove(&hwmon_ida, id);
  71         } else
  72                 dev_dbg(dev->parent,
  73                         "hwmon_device_unregister() failed: bad class ID!\n");
  74 }
  75
  76 static void __init hwmon_pci_quirks(void)
  77 {
  78 #if defined CONFIG_X86 && defined CONFIG_PCI
  79         struct pci_dev *sb;
  80         u16 base;
  81         u8 enable;
  82
  83         /* Open access to 0x295-0x296 on MSI MS-7031 */
  84         sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
  85         if (sb &&
  86             (sb->subsystem_vendor == 0x1462 &&  /* MSI */
  87              sb->subsystem_device == 0x0031)) { /* MS-7031 */
  88
  89                 pci_read_config_byte(sb, 0x48, &enable);
  90                 pci_read_config_word(sb, 0x64, &base);
  91
  92                 if (base == 0 && !(enable & BIT(2))) {
  93                         dev_info(&sb->dev,
  94                                  "Opening wide generic port at 0x295\n");
  95                         pci_write_config_word(sb, 0x64, 0x295);
  96                         pci_write_config_byte(sb, 0x48, enable | BIT(2));
  97                 }
  98         }
  99 #endif
 100 }
 101
 102 static int __init hwmon_init(void)
 103 {
 104         hwmon_pci_quirks();
 105
 106         hwmon_class = class_create(THIS_MODULE, "hwmon");
 107         if (IS_ERR(hwmon_class)) {
 108                 pr_err("couldn't create sysfs class\n");
 109                 return PTR_ERR(hwmon_class);
 110         }
 111         return 0;
 112 }
 113
 114 static void __exit hwmon_exit(void)
 115 {
 116         class_destroy(hwmon_class);
 117 }
 118
 119 subsys_initcall(hwmon_init);
 120 module_exit(hwmon_exit);
 121
 122 EXPORT_SYMBOL_GPL(hwmon_device_register);
 123 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
 124
 125 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 126 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
 127 MODULE_LICENSE("GPL");
 128