linux-imx

/*

 * RTC subsystem, dev interface

 *

 * Copyright (C) 2005 Tower Technologies

 * Author: Alessandro Zummo <a.zummo@towertech.it>

 *

 * based on arch/arm/common/rtctime.c

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

*/

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/rtc.h>

#include <linux/sched/signal.h>

#include "rtc-core.h"

​

static dev_t rtc_devt;

​

#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */

​

static int rtc_dev_open(struct inode *inode, struct file *file)

{

    struct rtc_device *rtc = container_of(inode->i_cdev,

                    struct rtc_device, char_dev);

​

    if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))

        return -EBUSY;

​

    file->private_data = rtc;

​

    spin_lock_irq(&rtc->irq_lock);

    rtc->irq_data = 0;

    spin_unlock_irq(&rtc->irq_lock);

​

    return 0;

}

​

#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL

/*

 * Routine to poll RTC seconds field for change as often as possible,

 * after first RTC_UIE use timer to reduce polling

 */

static void rtc_uie_task(struct work_struct *work)

{

    struct rtc_device *rtc =

        container_of(work, struct rtc_device, uie_task);

    struct rtc_time tm;

    int num = 0;

    int err;

​

    err = rtc_read_time(rtc, &tm);

​

    spin_lock_irq(&rtc->irq_lock);

    if (rtc->stop_uie_polling || err) {

        rtc->uie_task_active = 0;

    } else if (rtc->oldsecs != tm.tm_sec) {

        num = (tm.tm_sec + 60 - rtc->oldsecs) % 60;

        rtc->oldsecs = tm.tm_sec;

        rtc->uie_timer.expires = jiffies + HZ - (HZ/10);

        rtc->uie_timer_active = 1;

        rtc->uie_task_active = 0;

        add_timer(&rtc->uie_timer);

    } else if (schedule_work(&rtc->uie_task) == 0) {

        rtc->uie_task_active = 0;

    }

    spin_unlock_irq(&rtc->irq_lock);

    if (num)

        rtc_handle_legacy_irq(rtc, num, RTC_UF);

}

static void rtc_uie_timer(struct timer_list *t)

{

    struct rtc_device *rtc = from_timer(rtc, t, uie_timer);

    unsigned long flags;

​

    spin_lock_irqsave(&rtc->irq_lock, flags);

    rtc->uie_timer_active = 0;

    rtc->uie_task_active = 1;

    if ((schedule_work(&rtc->uie_task) == 0))

        rtc->uie_task_active = 0;

    spin_unlock_irqrestore(&rtc->irq_lock, flags);

}

​

static int clear_uie(struct rtc_device *rtc)

{

    spin_lock_irq(&rtc->irq_lock);

    if (rtc->uie_irq_active) {

        rtc->stop_uie_polling = 1;

        if (rtc->uie_timer_active) {