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 #include <linux/module.h> 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/kdev_t.h> 17 #include <linux/idr.h> 18 #include <linux/hwmon.h> 19 20 #define HWMON_ID_PREFIX "hwmon" 21 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d" 22 23 static struct class *hwmon_class; 24 25 static DEFINE_IDR(hwmon_idr); 26 27 /** 28 * hwmon_device_register - register w/ hwmon sysfs class 29 * @dev: the device to register 30 * 31 * hwmon_device_unregister() must be called when the class device is no 32 * longer needed. 33 * 34 * Returns the pointer to the new struct class device. 35 */ 36 struct class_device *hwmon_device_register(struct device *dev) 37 { 38 struct class_device *cdev; 39 int id; 40 41 if (idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0) 42 return ERR_PTR(-ENOMEM); 43 44 if (idr_get_new(&hwmon_idr, NULL, &id) < 0) 45 return ERR_PTR(-ENOMEM); 46 47 id = id & MAX_ID_MASK; 48 cdev = class_device_create(hwmon_class, NULL, MKDEV(0,0), dev, 49 HWMON_ID_FORMAT, id); 50 51 if (IS_ERR(cdev)) 52 idr_remove(&hwmon_idr, id); 53 54 return cdev; 55 } 56 57 /** 58 * hwmon_device_unregister - removes the previously registered class device 59 * 60 * @cdev: the class device to destroy 61 */ 62 void hwmon_device_unregister(struct class_device *cdev) 63 { 64 int id; 65 66 if (sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1) { 67 class_device_unregister(cdev); 68 idr_remove(&hwmon_idr, id); 69 } else 70 dev_dbg(cdev->dev, 71 "hwmon_device_unregister() failed: bad class ID!\n"); 72 } 73 74 static int __init hwmon_init(void) 75 { 76 hwmon_class = class_create(THIS_MODULE, "hwmon"); 77 if (IS_ERR(hwmon_class)) { 78 printk(KERN_ERR "hwmon.c: couldn't create sysfs class\n"); 79 return PTR_ERR(hwmon_class); 80 } 81 return 0; 82 } 83 84 static void __exit hwmon_exit(void) 85 { 86 class_destroy(hwmon_class); 87 } 88 89 module_init(hwmon_init); 90 module_exit(hwmon_exit); 91 92 EXPORT_SYMBOL_GPL(hwmon_device_register); 93 EXPORT_SYMBOL_GPL(hwmon_device_unregister); 94 95 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); 96 MODULE_DESCRIPTION("hardware monitoring sysfs/class support"); 97 MODULE_LICENSE("GPL"); 98 99