1 /* 2 * RTC subsystem, base class 3 * 4 * Copyright (C) 2005 Tower Technologies 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * 7 * class skeleton from drivers/hwmon/hwmon.c 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/module.h> 15 #include <linux/rtc.h> 16 #include <linux/kdev_t.h> 17 #include <linux/idr.h> 18 #include <linux/slab.h> 19 #include <linux/workqueue.h> 20 21 #include "rtc-core.h" 22 23 24 static DEFINE_IDR(rtc_idr); 25 static DEFINE_MUTEX(idr_lock); 26 struct class *rtc_class; 27 28 static void rtc_device_release(struct device *dev) 29 { 30 struct rtc_device *rtc = to_rtc_device(dev); 31 mutex_lock(&idr_lock); 32 idr_remove(&rtc_idr, rtc->id); 33 mutex_unlock(&idr_lock); 34 kfree(rtc); 35 } 36 37 #if defined(CONFIG_PM) && defined(CONFIG_RTC_HCTOSYS_DEVICE) 38 39 /* 40 * On suspend(), measure the delta between one RTC and the 41 * system's wall clock; restore it on resume(). 42 */ 43 44 static struct timespec delta; 45 static time_t oldtime; 46 47 static int rtc_suspend(struct device *dev, pm_message_t mesg) 48 { 49 struct rtc_device *rtc = to_rtc_device(dev); 50 struct rtc_time tm; 51 struct timespec ts = current_kernel_time(); 52 53 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) 54 return 0; 55 56 rtc_read_time(rtc, &tm); 57 rtc_tm_to_time(&tm, &oldtime); 58 59 /* RTC precision is 1 second; adjust delta for avg 1/2 sec err */ 60 set_normalized_timespec(&delta, 61 ts.tv_sec - oldtime, 62 ts.tv_nsec - (NSEC_PER_SEC >> 1)); 63 64 return 0; 65 } 66 67 static int rtc_resume(struct device *dev) 68 { 69 struct rtc_device *rtc = to_rtc_device(dev); 70 struct rtc_time tm; 71 time_t newtime; 72 struct timespec time; 73 74 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) 75 return 0; 76 77 rtc_read_time(rtc, &tm); 78 if (rtc_valid_tm(&tm) != 0) { 79 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev)); 80 return 0; 81 } 82 rtc_tm_to_time(&tm, &newtime); 83 if (newtime <= oldtime) { 84 if (newtime < oldtime) 85 pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); 86 return 0; 87 } 88 89 /* restore wall clock using delta against this RTC; 90 * adjust again for avg 1/2 second RTC sampling error 91 */ 92 set_normalized_timespec(&time, 93 newtime + delta.tv_sec, 94 (NSEC_PER_SEC >> 1) + delta.tv_nsec); 95 do_settimeofday(&time); 96 97 return 0; 98 } 99 100 #else 101 #define rtc_suspend NULL 102 #define rtc_resume NULL 103 #endif 104 105 106 /** 107 * rtc_device_register - register w/ RTC class 108 * @dev: the device to register 109 * 110 * rtc_device_unregister() must be called when the class device is no 111 * longer needed. 112 * 113 * Returns the pointer to the new struct class device. 114 */ 115 struct rtc_device *rtc_device_register(const char *name, struct device *dev, 116 const struct rtc_class_ops *ops, 117 struct module *owner) 118 { 119 struct rtc_device *rtc; 120 int id, err; 121 122 if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { 123 err = -ENOMEM; 124 goto exit; 125 } 126 127 128 mutex_lock(&idr_lock); 129 err = idr_get_new(&rtc_idr, NULL, &id); 130 mutex_unlock(&idr_lock); 131 132 if (err < 0) 133 goto exit; 134 135 id = id & MAX_ID_MASK; 136 137 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); 138 if (rtc == NULL) { 139 err = -ENOMEM; 140 goto exit_idr; 141 } 142 143 rtc->id = id; 144 rtc->ops = ops; 145 rtc->owner = owner; 146 rtc->max_user_freq = 64; 147 rtc->dev.parent = dev; 148 rtc->dev.class = rtc_class; 149 rtc->dev.release = rtc_device_release; 150 151 mutex_init(&rtc->ops_lock); 152 spin_lock_init(&rtc->irq_lock); 153 spin_lock_init(&rtc->irq_task_lock); 154 init_waitqueue_head(&rtc->irq_queue); 155 156 /* Init timerqueue */ 157 timerqueue_init_head(&rtc->timerqueue); 158 INIT_WORK(&rtc->irqwork, rtc_timer_do_work); 159 /* Init aie timer */ 160 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc); 161 /* Init uie timer */ 162 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc); 163 /* Init pie timer */ 164 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 165 rtc->pie_timer.function = rtc_pie_update_irq; 166 rtc->pie_enabled = 0; 167 168 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); 169 dev_set_name(&rtc->dev, "rtc%d", id); 170 171 rtc_dev_prepare(rtc); 172 173 err = device_register(&rtc->dev); 174 if (err) { 175 put_device(&rtc->dev); 176 goto exit_kfree; 177 } 178 179 rtc_dev_add_device(rtc); 180 rtc_sysfs_add_device(rtc); 181 rtc_proc_add_device(rtc); 182 183 dev_info(dev, "rtc core: registered %s as %s\n", 184 rtc->name, dev_name(&rtc->dev)); 185 186 return rtc; 187 188 exit_kfree: 189 kfree(rtc); 190 191 exit_idr: 192 mutex_lock(&idr_lock); 193 idr_remove(&rtc_idr, id); 194 mutex_unlock(&idr_lock); 195 196 exit: 197 dev_err(dev, "rtc core: unable to register %s, err = %d\n", 198 name, err); 199 return ERR_PTR(err); 200 } 201 EXPORT_SYMBOL_GPL(rtc_device_register); 202 203 204 /** 205 * rtc_device_unregister - removes the previously registered RTC class device 206 * 207 * @rtc: the RTC class device to destroy 208 */ 209 void rtc_device_unregister(struct rtc_device *rtc) 210 { 211 if (get_device(&rtc->dev) != NULL) { 212 mutex_lock(&rtc->ops_lock); 213 /* remove innards of this RTC, then disable it, before 214 * letting any rtc_class_open() users access it again 215 */ 216 rtc_sysfs_del_device(rtc); 217 rtc_dev_del_device(rtc); 218 rtc_proc_del_device(rtc); 219 device_unregister(&rtc->dev); 220 rtc->ops = NULL; 221 mutex_unlock(&rtc->ops_lock); 222 put_device(&rtc->dev); 223 } 224 } 225 EXPORT_SYMBOL_GPL(rtc_device_unregister); 226 227 static int __init rtc_init(void) 228 { 229 rtc_class = class_create(THIS_MODULE, "rtc"); 230 if (IS_ERR(rtc_class)) { 231 printk(KERN_ERR "%s: couldn't create class\n", __FILE__); 232 return PTR_ERR(rtc_class); 233 } 234 rtc_class->suspend = rtc_suspend; 235 rtc_class->resume = rtc_resume; 236 rtc_dev_init(); 237 rtc_sysfs_init(rtc_class); 238 return 0; 239 } 240 241 static void __exit rtc_exit(void) 242 { 243 rtc_dev_exit(); 244 class_destroy(rtc_class); 245 idr_destroy(&rtc_idr); 246 } 247 248 subsys_initcall(rtc_init); 249 module_exit(rtc_exit); 250 251 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 252 MODULE_DESCRIPTION("RTC class support"); 253 MODULE_LICENSE("GPL"); 254