/* 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 <mhoffman@lightlink.com> 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. */ #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> #define HWMON_ID_PREFIX "hwmon" #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d" static struct class *hwmon_class; static DEFINE_IDR(hwmon_idr); static DEFINE_SPINLOCK(idr_lock); /** * hwmon_device_register - register w/ hwmon sysfs class * @dev: the device to register * * hwmon_device_unregister() must be called when the class device is no * longer needed. * * Returns the pointer to the new struct class device. */ struct class_device *hwmon_device_register(struct device *dev) { struct class_device *cdev; int id, err; again: if (unlikely(idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0)) return ERR_PTR(-ENOMEM); spin_lock(&idr_lock); err = idr_get_new(&hwmon_idr, NULL, &id); spin_unlock(&idr_lock); if (unlikely(err == -EAGAIN)) goto again; else if (unlikely(err)) return ERR_PTR(err); id = id & MAX_ID_MASK; cdev = class_device_create(hwmon_class, NULL, MKDEV(0,0), dev, HWMON_ID_FORMAT, id); if (IS_ERR(cdev)) { spin_lock(&idr_lock); idr_remove(&hwmon_idr, id); spin_unlock(&idr_lock); } return cdev; } /** * hwmon_device_unregister - removes the previously registered class device * * @cdev: the class device to destroy */ void hwmon_device_unregister(struct class_device *cdev) { int id; if (likely(sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1)) { class_device_unregister(cdev); spin_lock(&idr_lock); idr_remove(&hwmon_idr, id); spin_unlock(&idr_lock); } else dev_dbg(cdev->dev, "hwmon_device_unregister() failed: bad class ID!\n"); } static int __init hwmon_init(void) { hwmon_class = class_create(THIS_MODULE, "hwmon"); if (IS_ERR(hwmon_class)) { printk(KERN_ERR "hwmon.c: 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); EXPORT_SYMBOL_GPL(hwmon_device_register); EXPORT_SYMBOL_GPL(hwmon_device_unregister); MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); MODULE_DESCRIPTION("hardware monitoring sysfs/class support"); MODULE_LICENSE("GPL");