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 #include <linux/gfp.h> 20 21 #define HWMON_ID_PREFIX "hwmon" 22 #define HWMON_ID_FORMAT HWMON_ID_PREFIX "%d" 23 24 static struct class *hwmon_class; 25 26 static DEFINE_IDR(hwmon_idr); 27 28 /** 29 * hwmon_device_register - register w/ hwmon sysfs class 30 * @dev: the device to register 31 * 32 * hwmon_device_unregister() must be called when the class device is no 33 * longer needed. 34 * 35 * Returns the pointer to the new struct class device. 36 */ 37 struct class_device *hwmon_device_register(struct device *dev) 38 { 39 struct class_device *cdev; 40 int id; 41 42 if (idr_pre_get(&hwmon_idr, GFP_KERNEL) == 0) 43 return ERR_PTR(-ENOMEM); 44 45 if (idr_get_new(&hwmon_idr, NULL, &id) < 0) 46 return ERR_PTR(-ENOMEM); 47 48 id = id & MAX_ID_MASK; 49 cdev = class_device_create(hwmon_class, NULL, MKDEV(0,0), dev, 50 HWMON_ID_FORMAT, id); 51 52 if (IS_ERR(cdev)) 53 idr_remove(&hwmon_idr, id); 54 55 return cdev; 56 } 57 58 /** 59 * hwmon_device_unregister - removes the previously registered class device 60 * 61 * @cdev: the class device to destroy 62 */ 63 void hwmon_device_unregister(struct class_device *cdev) 64 { 65 int id; 66 67 if (sscanf(cdev->class_id, HWMON_ID_FORMAT, &id) == 1) { 68 class_device_unregister(cdev); 69 idr_remove(&hwmon_idr, id); 70 } else 71 dev_dbg(cdev->dev, 72 "hwmon_device_unregister() failed: bad class ID!\n"); 73 } 74 75 static int __init hwmon_init(void) 76 { 77 hwmon_class = class_create(THIS_MODULE, "hwmon"); 78 if (IS_ERR(hwmon_class)) { 79 printk(KERN_ERR "hwmon.c: couldn't create sysfs class\n"); 80 return PTR_ERR(hwmon_class); 81 } 82 return 0; 83 } 84 85 static void __exit hwmon_exit(void) 86 { 87 class_destroy(hwmon_class); 88 } 89 90 module_init(hwmon_init); 91 module_exit(hwmon_exit); 92 93 EXPORT_SYMBOL_GPL(hwmon_device_register); 94 EXPORT_SYMBOL_GPL(hwmon_device_unregister); 95 96 MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>"); 97 MODULE_DESCRIPTION("hardware monitoring sysfs/class support"); 98 MODULE_LICENSE("GPL"); 99 100