hwmon.c

Go to the documentation of this file.

/*
 * hwmon.c - part of lm_sensors, Linux kernel modules for hardware monitoring
 *
 * This file defines the sysfs class "hwmon", for use by sensors drivers.
 *
 * Copyright (C) 2005 Mark M. Hoffman <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/hwmon.h>
#include <linux/gfp.h>
#include <linux/spinlock.h>
#include <linux/pci.h>

#define HWMON_ID_PREFIX "hwmon"
#define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d"

static struct class *hwmon_class;

static DEFINE_IDA(hwmon_ida);

struct device *hwmon_device_register(struct device *dev)
{
    struct device *hwdev;
    int id;

    id = ida_simple_get(&hwmon_ida, 0, 0, GFP_KERNEL);
    if (id < 0)
        return ERR_PTR(id);

    hwdev = device_create(hwmon_class, dev, MKDEV(0, 0), NULL,
                  HWMON_ID_FORMAT, id);

    if (IS_ERR(hwdev))
        ida_simple_remove(&hwmon_ida, id);

    return hwdev;
}
EXPORT_SYMBOL_GPL(hwmon_device_register);

void hwmon_device_unregister(struct device *dev)
{
    int id;

    if (likely(sscanf(dev_name(dev), HWMON_ID_FORMAT, &id) == 1)) {
        device_unregister(dev);
        ida_simple_remove(&hwmon_ida, id);
    } else
        dev_dbg(dev->parent,
            "hwmon_device_unregister() failed: bad class ID!\n");
}
EXPORT_SYMBOL_GPL(hwmon_device_unregister);

static void __init hwmon_pci_quirks(void)
{
#if defined CONFIG_X86 && defined CONFIG_PCI
    struct pci_dev *sb;
    u16 base;
    u8 enable;

    /* Open access to 0x295-0x296 on MSI MS-7031 */
    sb = pci_get_device(PCI_VENDOR_ID_ATI, 0x436c, NULL);
    if (sb &&
        (sb->subsystem_vendor == 0x1462 &&  /* MSI */
         sb->subsystem_device == 0x0031)) { /* MS-7031 */

        pci_read_config_byte(sb, 0x48, &enable);
        pci_read_config_word(sb, 0x64, &base);

        if (base == 0 && !(enable & BIT(2))) {
            dev_info(&sb->dev,
                 "Opening wide generic port at 0x295\n");
            pci_write_config_word(sb, 0x64, 0x295);
            pci_write_config_byte(sb, 0x48, enable | BIT(2));
        }
    }
#endif
}

static int __init hwmon_init(void)
{
    hwmon_pci_quirks();

    hwmon_class = class_create(THIS_MODULE, "hwmon");
    if (IS_ERR(hwmon_class)) {
        pr_err("couldn't create sysfs class\n");
        return PTR_ERR(hwmon_class);
    }
    return 0;
}

static void __exit hwmon_exit(void)
{
    class_destroy(hwmon_class);
}

subsys_initcall(hwmon_init);
module_exit(hwmon_exit);

MODULE_AUTHOR("Mark M. Hoffman <[email protected]>");
MODULE_DESCRIPTION("hardware monitoring sysfs/class support");
MODULE_LICENSE("GPL");