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 EXPORT_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  */
  65 void 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 }
  76 EXPORT_SYMBOL_GPL(hwmon_device_unregister);
  77
  78 static 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
 104 static 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
 116 static void __exit hwmon_exit(void)
 117 {
 118         class_destroy(hwmon_class);
 119 }
 120
 121 subsys_initcall(hwmon_init);
 122 module_exit(hwmon_exit);
 123
 124 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
 125 MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
 126 MODULE_LICENSE("GPL");
 127