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 time_t oldtime; 45 static struct timespec oldts; 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 52 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) 53 return 0; 54 55 rtc_read_time(rtc, &tm); 56 ktime_get_ts(&oldts); 57 rtc_tm_to_time(&tm, &oldtime); 58 59 return 0; 60 } 61 62 static int rtc_resume(struct device *dev) 63 { 64 struct rtc_device *rtc = to_rtc_device(dev); 65 struct rtc_time tm; 66 time_t newtime; 67 struct timespec time; 68 struct timespec newts; 69 70 if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) 71 return 0; 72 73 ktime_get_ts(&newts); 74 rtc_read_time(rtc, &tm); 75 if (rtc_valid_tm(&tm) != 0) { 76 pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev)); 77 return 0; 78 } 79 rtc_tm_to_time(&tm, &newtime); 80 if (newtime <= oldtime) { 81 if (newtime < oldtime) 82 pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); 83 return 0; 84 } 85 /* calculate the RTC time delta */ 86 set_normalized_timespec(&time, newtime - oldtime, 0); 87 88 /* subtract kernel time between rtc_suspend to rtc_resume */ 89 time = timespec_sub(time, timespec_sub(newts, oldts)); 90 91 timekeeping_inject_sleeptime(&time); 92 return 0; 93 } 94 95 #else 96 #define rtc_suspend NULL 97 #define rtc_resume NULL 98 #endif 99 100 101 /** 102 * rtc_device_register - register w/ RTC class 103 * @dev: the device to register 104 * 105 * rtc_device_unregister() must be called when the class device is no 106 * longer needed. 107 * 108 * Returns the pointer to the new struct class device. 109 */ 110 struct rtc_device *rtc_device_register(const char *name, struct device *dev, 111 const struct rtc_class_ops *ops, 112 struct module *owner) 113 { 114 struct rtc_device *rtc; 115 struct rtc_wkalrm alrm; 116 int id, err; 117 118 if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) { 119 err = -ENOMEM; 120 goto exit; 121 } 122 123 124 mutex_lock(&idr_lock); 125 err = idr_get_new(&rtc_idr, NULL, &id); 126 mutex_unlock(&idr_lock); 127 128 if (err < 0) 129 goto exit; 130 131 id = id & MAX_ID_MASK; 132 133 rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL); 134 if (rtc == NULL) { 135 err = -ENOMEM; 136 goto exit_idr; 137 } 138 139 rtc->id = id; 140 rtc->ops = ops; 141 rtc->owner = owner; 142 rtc->irq_freq = 1; 143 rtc->max_user_freq = 64; 144 rtc->dev.parent = dev; 145 rtc->dev.class = rtc_class; 146 rtc->dev.release = rtc_device_release; 147 148 mutex_init(&rtc->ops_lock); 149 spin_lock_init(&rtc->irq_lock); 150 spin_lock_init(&rtc->irq_task_lock); 151 init_waitqueue_head(&rtc->irq_queue); 152 153 /* Init timerqueue */ 154 timerqueue_init_head(&rtc->timerqueue); 155 INIT_WORK(&rtc->irqwork, rtc_timer_do_work); 156 /* Init aie timer */ 157 rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, (void *)rtc); 158 /* Init uie timer */ 159 rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, (void *)rtc); 160 /* Init pie timer */ 161 hrtimer_init(&rtc->pie_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 162 rtc->pie_timer.function = rtc_pie_update_irq; 163 rtc->pie_enabled = 0; 164 165 /* Check to see if there is an ALARM already set in hw */ 166 err = __rtc_read_alarm(rtc, &alrm); 167 168 if (!err && !rtc_valid_tm(&alrm.time)) 169 rtc_initialize_alarm(rtc, &alrm); 170 171 strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE); 172 dev_set_name(&rtc->dev, "rtc%d", id); 173 174 rtc_dev_prepare(rtc); 175 176 err = device_register(&rtc->dev); 177 if (err) { 178 put_device(&rtc->dev); 179 goto exit_kfree; 180 } 181 182 rtc_dev_add_device(rtc); 183 rtc_sysfs_add_device(rtc); 184 rtc_proc_add_device(rtc); 185 186 dev_info(dev, "rtc core: registered %s as %s\n", 187 rtc->name, dev_name(&rtc->dev)); 188 189 return rtc; 190 191 exit_kfree: 192 kfree(rtc); 193 194 exit_idr: 195 mutex_lock(&idr_lock); 196 idr_remove(&rtc_idr, id); 197 mutex_unlock(&idr_lock); 198 199 exit: 200 dev_err(dev, "rtc core: unable to register %s, err = %d\n", 201 name, err); 202 return ERR_PTR(err); 203 } 204 EXPORT_SYMBOL_GPL(rtc_device_register); 205 206 207 /** 208 * rtc_device_unregister - removes the previously registered RTC class device 209 * 210 * @rtc: the RTC class device to destroy 211 */ 212 void rtc_device_unregister(struct rtc_device *rtc) 213 { 214 if (get_device(&rtc->dev) != NULL) { 215 mutex_lock(&rtc->ops_lock); 216 /* remove innards of this RTC, then disable it, before 217 * letting any rtc_class_open() users access it again 218 */ 219 rtc_sysfs_del_device(rtc); 220 rtc_dev_del_device(rtc); 221 rtc_proc_del_device(rtc); 222 device_unregister(&rtc->dev); 223 rtc->ops = NULL; 224 mutex_unlock(&rtc->ops_lock); 225 put_device(&rtc->dev); 226 } 227 } 228 EXPORT_SYMBOL_GPL(rtc_device_unregister); 229 230 static int __init rtc_init(void) 231 { 232 rtc_class = class_create(THIS_MODULE, "rtc"); 233 if (IS_ERR(rtc_class)) { 234 printk(KERN_ERR "%s: couldn't create class\n", __FILE__); 235 return PTR_ERR(rtc_class); 236 } 237 rtc_class->suspend = rtc_suspend; 238 rtc_class->resume = rtc_resume; 239 rtc_dev_init(); 240 rtc_sysfs_init(rtc_class); 241 return 0; 242 } 243 244 static void __exit rtc_exit(void) 245 { 246 rtc_dev_exit(); 247 class_destroy(rtc_class); 248 idr_destroy(&rtc_idr); 249 } 250 251 subsys_initcall(rtc_init); 252 module_exit(rtc_exit); 253 254 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); 255 MODULE_DESCRIPTION("RTC class support"); 256 MODULE_LICENSE("GPL"); 257