[PATCH] RTC subsystem: class
Add the basic RTC subsystem infrastructure to the kernel. rtc/class.c - registration facilities for RTC drivers rtc/interface.c - kernel/rtc interface functions rtc/hctosys.c - snippet of code that copies hw clock to sw clock at bootup, if configured to do so. Signed-off-by: Alessandro Zummo <a.zummo@towertech.it> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Alessandro Zummo
committed by
Linus Torvalds
Linus Torvalds
parent
4079c39aaa
commit
0c86edc0d4
@@ -1,6 +1,46 @@
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#
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\#
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# RTC class/drivers configuration
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#
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menu "Real Time Clock"
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config RTC_LIB
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tristate
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tristate
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config RTC_CLASS
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tristate "RTC class"
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depends on EXPERIMENTAL
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default n
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select RTC_LIB
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help
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Generic RTC class support. If you say yes here, you will
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be allowed to plug one or more RTCs to your system. You will
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probably want to enable one of more of the interfaces below.
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This driver can also be built as a module. If so, the module
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will be called rtc-class.
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config RTC_HCTOSYS
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bool "Set system time from RTC on startup"
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depends on RTC_CLASS = y
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default y
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help
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If you say yes here, the system time will be set using
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the value read from the specified RTC device. This is useful
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in order to avoid unnecessary fschk runs.
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config RTC_HCTOSYS_DEVICE
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string "The RTC to read the time from"
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depends on RTC_HCTOSYS = y
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default "rtc0"
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help
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The RTC device that will be used as the source for
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the system time, usually rtc0.
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comment "RTC interfaces"
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depends on RTC_CLASS
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comment "RTC drivers"
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depends on RTC_CLASS
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endmenu
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@@ -2,4 +2,7 @@
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# Makefile for RTC class/drivers.
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#
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obj-$(CONFIG_RTC_LIB) += rtc-lib.o
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obj-$(CONFIG_RTC_LIB) += rtc-lib.o
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obj-$(CONFIG_RTC_HCTOSYS) += hctosys.o
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obj-$(CONFIG_RTC_CLASS) += rtc-core.o
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rtc-core-y := class.o interface.o
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145
drivers/rtc/class.c
Normal file
145
drivers/rtc/class.c
Normal file
@@ -0,0 +1,145 @@
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/*
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* RTC subsystem, base class
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* class skeleton from drivers/hwmon/hwmon.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/rtc.h>
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#include <linux/kdev_t.h>
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#include <linux/idr.h>
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static DEFINE_IDR(rtc_idr);
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static DEFINE_MUTEX(idr_lock);
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struct class *rtc_class;
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static void rtc_device_release(struct class_device *class_dev)
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{
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struct rtc_device *rtc = to_rtc_device(class_dev);
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mutex_lock(&idr_lock);
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idr_remove(&rtc_idr, rtc->id);
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mutex_unlock(&idr_lock);
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kfree(rtc);
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}
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/**
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* rtc_device_register - register w/ RTC class
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* @dev: the device to register
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*
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* rtc_device_unregister() must be called when the class device is no
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* longer needed.
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*
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* Returns the pointer to the new struct class device.
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*/
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struct rtc_device *rtc_device_register(const char *name, struct device *dev,
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struct rtc_class_ops *ops,
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struct module *owner)
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{
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struct rtc_device *rtc;
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int id, err;
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if (idr_pre_get(&rtc_idr, GFP_KERNEL) == 0) {
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err = -ENOMEM;
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goto exit;
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}
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mutex_lock(&idr_lock);
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err = idr_get_new(&rtc_idr, NULL, &id);
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mutex_unlock(&idr_lock);
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if (err < 0)
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goto exit;
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id = id & MAX_ID_MASK;
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rtc = kzalloc(sizeof(struct rtc_device), GFP_KERNEL);
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if (rtc == NULL) {
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err = -ENOMEM;
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goto exit_idr;
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}
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rtc->id = id;
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rtc->ops = ops;
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rtc->owner = owner;
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rtc->class_dev.dev = dev;
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rtc->class_dev.class = rtc_class;
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rtc->class_dev.release = rtc_device_release;
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mutex_init(&rtc->ops_lock);
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spin_lock_init(&rtc->irq_lock);
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spin_lock_init(&rtc->irq_task_lock);
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strlcpy(rtc->name, name, RTC_DEVICE_NAME_SIZE);
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snprintf(rtc->class_dev.class_id, BUS_ID_SIZE, "rtc%d", id);
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err = class_device_register(&rtc->class_dev);
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if (err)
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goto exit_kfree;
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dev_info(dev, "rtc core: registered %s as %s\n",
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rtc->name, rtc->class_dev.class_id);
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return rtc;
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exit_kfree:
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kfree(rtc);
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exit_idr:
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idr_remove(&rtc_idr, id);
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exit:
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return ERR_PTR(err);
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}
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EXPORT_SYMBOL_GPL(rtc_device_register);
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/**
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* rtc_device_unregister - removes the previously registered RTC class device
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*
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* @rtc: the RTC class device to destroy
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*/
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void rtc_device_unregister(struct rtc_device *rtc)
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{
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mutex_lock(&rtc->ops_lock);
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rtc->ops = NULL;
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mutex_unlock(&rtc->ops_lock);
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class_device_unregister(&rtc->class_dev);
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}
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EXPORT_SYMBOL_GPL(rtc_device_unregister);
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int rtc_interface_register(struct class_interface *intf)
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{
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intf->class = rtc_class;
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return class_interface_register(intf);
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}
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EXPORT_SYMBOL_GPL(rtc_interface_register);
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static int __init rtc_init(void)
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{
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rtc_class = class_create(THIS_MODULE, "rtc");
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if (IS_ERR(rtc_class)) {
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printk(KERN_ERR "%s: couldn't create class\n", __FILE__);
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return PTR_ERR(rtc_class);
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}
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return 0;
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}
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static void __exit rtc_exit(void)
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{
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class_destroy(rtc_class);
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}
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module_init(rtc_init);
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module_exit(rtc_exit);
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MODULE_AUTHOR("Alessandro Zummo <a.zummo@towerteh.it>");
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MODULE_DESCRIPTION("RTC class support");
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MODULE_LICENSE("GPL");
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69
drivers/rtc/hctosys.c
Normal file
69
drivers/rtc/hctosys.c
Normal file
@@ -0,0 +1,69 @@
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/*
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* RTC subsystem, initialize system time on startup
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/rtc.h>
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/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary
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* whether it stores the most close value or the value with partial
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* seconds truncated. However, it is important that we use it to store
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* the truncated value. This is because otherwise it is necessary,
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* in an rtc sync function, to read both xtime.tv_sec and
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* xtime.tv_nsec. On some processors (i.e. ARM), an atomic read
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* of >32bits is not possible. So storing the most close value would
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* slow down the sync API. So here we have the truncated value and
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* the best guess is to add 0.5s.
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*/
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static int __init rtc_hctosys(void)
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{
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int err;
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struct rtc_time tm;
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struct class_device *class_dev = rtc_class_open(CONFIG_RTC_HCTOSYS_DEVICE);
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if (class_dev == NULL) {
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printk("%s: unable to open rtc device (%s)\n",
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__FILE__, CONFIG_RTC_HCTOSYS_DEVICE);
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return -ENODEV;
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}
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err = rtc_read_time(class_dev, &tm);
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if (err == 0) {
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err = rtc_valid_tm(&tm);
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if (err == 0) {
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struct timespec tv;
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tv.tv_nsec = NSEC_PER_SEC >> 1;
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rtc_tm_to_time(&tm, &tv.tv_sec);
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do_settimeofday(&tv);
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dev_info(class_dev->dev,
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"setting the system clock to "
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"%d-%02d-%02d %02d:%02d:%02d (%u)\n",
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tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
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tm.tm_hour, tm.tm_min, tm.tm_sec,
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(unsigned int) tv.tv_sec);
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}
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else
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dev_err(class_dev->dev,
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"hctosys: invalid date/time\n");
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}
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else
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dev_err(class_dev->dev,
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"hctosys: unable to read the hardware clock\n");
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rtc_class_close(class_dev);
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return 0;
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}
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late_initcall(rtc_hctosys);
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277
drivers/rtc/interface.c
Normal file
277
drivers/rtc/interface.c
Normal file
@@ -0,0 +1,277 @@
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/*
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* RTC subsystem, interface functions
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* based on arch/arm/common/rtctime.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/rtc.h>
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int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->read_time)
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err = -EINVAL;
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else {
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memset(tm, 0, sizeof(struct rtc_time));
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err = rtc->ops->read_time(class_dev->dev, tm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_read_time);
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int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = rtc_valid_tm(tm);
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if (err != 0)
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return err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_time)
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err = -EINVAL;
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else
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err = rtc->ops->set_time(class_dev->dev, tm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_time);
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int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (rtc->ops->set_mmss)
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err = rtc->ops->set_mmss(class_dev->dev, secs);
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else if (rtc->ops->read_time && rtc->ops->set_time) {
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struct rtc_time new, old;
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err = rtc->ops->read_time(class_dev->dev, &old);
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if (err == 0) {
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rtc_time_to_tm(secs, &new);
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/*
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* avoid writing when we're going to change the day of
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* the month. We will retry in the next minute. This
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* basically means that if the RTC must not drift
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* by more than 1 minute in 11 minutes.
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*/
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if (!((old.tm_hour == 23 && old.tm_min == 59) ||
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(new.tm_hour == 23 && new.tm_min == 59)))
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err = rtc->ops->set_time(class_dev->dev, &new);
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}
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}
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else
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err = -EINVAL;
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_mmss);
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int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (rtc->ops == NULL)
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err = -ENODEV;
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else if (!rtc->ops->read_alarm)
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err = -EINVAL;
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else {
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memset(alarm, 0, sizeof(struct rtc_wkalrm));
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err = rtc->ops->read_alarm(class_dev->dev, alarm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_read_alarm);
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int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_alarm)
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err = -EINVAL;
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else
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err = rtc->ops->set_alarm(class_dev->dev, alarm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_alarm);
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void rtc_update_irq(struct class_device *class_dev,
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unsigned long num, unsigned long events)
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{
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struct rtc_device *rtc = to_rtc_device(class_dev);
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spin_lock(&rtc->irq_lock);
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rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
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spin_unlock(&rtc->irq_lock);
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spin_lock(&rtc->irq_task_lock);
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if (rtc->irq_task)
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rtc->irq_task->func(rtc->irq_task->private_data);
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spin_unlock(&rtc->irq_task_lock);
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wake_up_interruptible(&rtc->irq_queue);
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kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
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}
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EXPORT_SYMBOL_GPL(rtc_update_irq);
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struct class_device *rtc_class_open(char *name)
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{
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struct class_device *class_dev = NULL,
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*class_dev_tmp;
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down(&rtc_class->sem);
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list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
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if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
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class_dev = class_dev_tmp;
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break;
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}
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}
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if (class_dev) {
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if (!try_module_get(to_rtc_device(class_dev)->owner))
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class_dev = NULL;
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}
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up(&rtc_class->sem);
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return class_dev;
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}
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EXPORT_SYMBOL_GPL(rtc_class_open);
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void rtc_class_close(struct class_device *class_dev)
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{
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module_put(to_rtc_device(class_dev)->owner);
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}
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EXPORT_SYMBOL_GPL(rtc_class_close);
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int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
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{
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int retval = -EBUSY;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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if (task == NULL || task->func == NULL)
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return -EINVAL;
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spin_lock(&rtc->irq_task_lock);
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if (rtc->irq_task == NULL) {
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rtc->irq_task = task;
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retval = 0;
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}
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spin_unlock(&rtc->irq_task_lock);
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return retval;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_register);
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|
||||
void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
|
||||
{
|
||||
struct rtc_device *rtc = to_rtc_device(class_dev);
|
||||
|
||||
spin_lock(&rtc->irq_task_lock);
|
||||
if (rtc->irq_task == task)
|
||||
rtc->irq_task = NULL;
|
||||
spin_unlock(&rtc->irq_task_lock);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(rtc_irq_unregister);
|
||||
|
||||
int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
|
||||
{
|
||||
int err = 0;
|
||||
unsigned long flags;
|
||||
struct rtc_device *rtc = to_rtc_device(class_dev);
|
||||
|
||||
spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
||||
if (rtc->irq_task != task)
|
||||
err = -ENXIO;
|
||||
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
||||
|
||||
if (err == 0)
|
||||
err = rtc->ops->irq_set_state(class_dev->dev, enabled);
|
||||
|
||||
return err;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(rtc_irq_set_state);
|
||||
|
||||
int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
|
||||
{
|
||||
int err = 0, tmp = 0;
|
||||
unsigned long flags;
|
||||
struct rtc_device *rtc = to_rtc_device(class_dev);
|
||||
|
||||
/* allowed range is 2-8192 */
|
||||
if (freq < 2 || freq > 8192)
|
||||
return -EINVAL;
|
||||
/*
|
||||
FIXME: this does not belong here, will move where appropriate
|
||||
at a later stage. It cannot hurt right now, trust me :)
|
||||
if ((freq > rtc_max_user_freq) && (!capable(CAP_SYS_RESOURCE)))
|
||||
return -EACCES;
|
||||
*/
|
||||
/* check if freq is a power of 2 */
|
||||
while (freq > (1 << tmp))
|
||||
tmp++;
|
||||
|
||||
if (freq != (1 << tmp))
|
||||
return -EINVAL;
|
||||
|
||||
spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
||||
if (rtc->irq_task != task)
|
||||
err = -ENXIO;
|
||||
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
||||
|
||||
if (err == 0) {
|
||||
err = rtc->ops->irq_set_freq(class_dev->dev, freq);
|
||||
if (err == 0)
|
||||
rtc->irq_freq = freq;
|
||||
}
|
||||
return err;
|
||||
}
|
||||
Reference in New Issue
Block a user