| 1 | |
| 2 | * RTC subsystem, base class
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| 3 | *
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| 4 | * Copyright (C) 2005 Tower Technologies
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| 5 | * Author: Alessandro Zummo <[email protected]>
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| 6 | *
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| 7 | * class skeleton from drivers/hwmon/hwmon.c
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| 8 | *
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| 9 | * This program is free software; you can redistribute it and/or modify
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| 10 | * it under the terms of the GNU General Public License version 2 as
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| 11 | * published by the Free Software Foundation.
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| 12 |
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| 13 |
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| 14 | #include <linux/module.h>
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| 15 | #include <linux/rtc.h>
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| 16 | #include <linux/kdev_t.h>
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| 17 | #include <linux/idr.h>
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| 18 |
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| 19 | static DEFINE_IDR(rtc_idr);
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| 20 | static DEFINE_MUTEX(idr_lock);
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| 21 | struct class *rtc_class;
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| 22 |
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| 23 | static void rtc_device_release(struct class_device *class_dev)
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| 24 | {
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| 25 | struct rtc_device *rtc = to_rtc_device(class_dev);
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| 26 | mutex_lock(&idr_lock);
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| 27 | idr_remove(&rtc_idr, rtc->id);
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| 28 | mutex_unlock(&idr_lock);
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| 29 | kfree(rtc);
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| 30 | }
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| 31 |
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| 32 | |
| 33 | * rtc_device_register - register w/ RTC class
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| 34 | * @dev: the device to register
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| 35 | *
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| 36 | * rtc_device_unregister() must be called when the class device is no
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| 37 | * longer needed.
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| 38 | *
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| 39 | * Returns the pointer to the new struct class device.
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| 40 |
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| 41 | struct rtc_device *rtc_device_register(const char *name, struct device *dev,
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| 42 | const struct rtc_class_ops *ops,
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| 43 | struct module *owner)
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| 44 | {
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| 45 | struct rtc_device *rtc;
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| 46 | int id, err;
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| 47 |
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| 48 | if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
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| 49 | err = -ENOMEM;
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| 50 | goto exit;
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| 51 | }
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| 52 |
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| 53 |
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| 54 | mutex_lock(&idr_lock);
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| 55 | err = idr_get_new(&rtc_idr, NULL, &id);
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| 56 | mutex_unlock(&idr_lock);
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| 57 |
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| 58 | if (err < 0)
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| 59 | goto exit;
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| 60 |
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| 61 | id = id & MAX_ID_MASK;
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| 62 |
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| 63 | rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
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| 64 | if (rtc == NULL) {
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| 65 | err = -ENOMEM;
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| 66 | goto exit_idr;
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| 67 | }
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| 68 |
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| 69 | rtc->id = id;
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| 70 | rtc->ops = ops;
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| 71 | rtc->owner = owner;
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| 72 | rtc->max_user_freq = 64;
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| 73 | rtc->class_dev.dev = dev;
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| 74 | rtc->class_dev.class = rtc_class;
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| 75 | rtc->class_dev.release = rtc_device_release;
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| 76 |
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| 77 | mutex_init(&rtc->ops_lock);
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| 78 | spin_lock_init(&rtc->irq_lock);
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| 79 | spin_lock_init(&rtc->irq_task_lock);
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| 80 |
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| 81 | strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
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| 82 | snprintf(rtc->class_dev.class_id, BUS_ID_SIZE, "rtc%d", id);
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| 83 |
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| 84 | err = class_device_register(&rtc->class_dev);
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| 85 | if (err)
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| 86 | goto exit_kfree;
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| 87 |
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| 88 | dev_info(dev, "rtc core: registered %s as %s\n",
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| 89 | rtc->name, rtc->class_dev.class_id);
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| 90 |
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| 91 | return rtc;
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| 92 |
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| 93 | exit_kfree:
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| 94 | kfree(rtc);
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| 95 |
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| 96 | exit_idr:
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| 97 | mutex_lock(&idr_lock);
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| 98 | idr_remove(&rtc_idr, id);
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| 99 | mutex_unlock(&idr_lock);
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| 100 |
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| 101 | exit:
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| 102 | dev_err(dev, "rtc core: unable to register %s, err = %d\n",
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| 103 | name, err);
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| 104 | return ERR_PTR(err);
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| 105 | }
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| 106 | EXPORT_SYMBOL_GPL(rtc_device_register);
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| 107 |
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| 108 |
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| 109 | |
| 110 | * rtc_device_unregister - removes the previously registered RTC class device
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| 111 | *
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| 112 | * @rtc: the RTC class device to destroy
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| 113 |
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| 114 | void rtc_device_unregister(struct rtc_device *rtc)
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| 115 | {
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| 116 | if (class_device_get(&rtc->class_dev) != NULL) {
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| 117 | mutex_lock(&rtc->ops_lock);
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| 118 | |
| 119 | * letting any rtc_class_open() users access it again
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| 120 |
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| 121 | class_device_unregister(&rtc->class_dev);
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| 122 | rtc->ops = NULL;
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| 123 | mutex_unlock(&rtc->ops_lock);
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| 124 | class_device_put(&rtc->class_dev);
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| 125 | }
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| 126 | }
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| 127 | EXPORT_SYMBOL_GPL(rtc_device_unregister);
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| 128 |
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| 129 | int rtc_interface_register(struct class_interface *intf)
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| 130 | {
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| 131 | intf->class = rtc_class;
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| 132 | return class_interface_register(intf);
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| 133 | }
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| 134 | EXPORT_SYMBOL_GPL(rtc_interface_register);
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| 135 |
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| 136 | static int __init rtc_init(void)
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| 137 | {
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| 138 | rtc_class = class_create(THIS_MODULE, "rtc");
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| 139 | if (IS_ERR(rtc_class)) {
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| 140 | printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
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| 141 | return PTR_ERR(rtc_class);
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| 142 | }
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| 143 | return 0;
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| 144 | }
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| 145 |
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| 146 | static void __exit rtc_exit(void)
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| 147 | {
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| 148 | class_destroy(rtc_class);
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| 149 | }
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| 150 |
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| 151 | subsys_initcall(rtc_init);
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| 152 | module_exit(rtc_exit);
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| 153 |
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| 154 | MODULE_AUTHOR("Alessandro Zummo <[email protected]>");
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| 155 | MODULE_DESCRIPTION("RTC class support");
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| 156 | MODULE_LICENSE("GPL");
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