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/*

 * RTC subsystem, sysfs interface

 *

 * Copyright (C) 2005 Tower Technologies

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

 *

 * 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.

*/

#include <linux/module.h>

#include <linux/rtc.h>

#include "rtc-core.h"

/* device attributes */

static ssize_t

rtc_sysfs_show_name(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        return sprintf(buf, "%s\n", to_rtc_device(dev)->name);

}

static ssize_t

rtc_sysfs_show_date(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        ssize_t retval;

        struct rtc_time tm;

        retval = rtc_read_time(to_rtc_device(dev), &tm);

        if (retval == 0) {

                retval = sprintf(buf, "%04d-%02d-%02d\n",

                        tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);

        }

        return retval;

}

static ssize_t

rtc_sysfs_show_time(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        ssize_t retval;

        struct rtc_time tm;

        retval = rtc_read_time(to_rtc_device(dev), &tm);

        if (retval == 0) {

                retval = sprintf(buf, "%02d:%02d:%02d\n",

                        tm.tm_hour, tm.tm_min, tm.tm_sec);

        }

        return retval;

}

static ssize_t

rtc_sysfs_show_since_epoch(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        ssize_t retval;

        struct rtc_time tm;

        retval = rtc_read_time(to_rtc_device(dev), &tm);

        if (retval == 0) {

                unsigned long time;

                rtc_tm_to_time(&tm, &time);

                retval = sprintf(buf, "%lu\n", time);

        }

        return retval;

}

static ssize_t

rtc_sysfs_show_max_user_freq(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        return sprintf(buf, "%d\n", to_rtc_device(dev)->max_user_freq);

}

static ssize_t

rtc_sysfs_set_max_user_freq(struct device *dev, struct device_attribute *attr,

                const char *buf, size_t n)

{

        struct rtc_device *rtc = to_rtc_device(dev);

        unsigned long val = simple_strtoul(buf, NULL, 0);

        if (val >= 4096 || val == 0)

                return -EINVAL;

        rtc->max_user_freq = (int)val;

        return n;

}

static struct device_attribute rtc_attrs[] = {

        __ATTR(name, S_IRUGO, rtc_sysfs_show_name, NULL),

        __ATTR(date, S_IRUGO, rtc_sysfs_show_date, NULL),

        __ATTR(time, S_IRUGO, rtc_sysfs_show_time, NULL),

        __ATTR(since_epoch, S_IRUGO, rtc_sysfs_show_since_epoch, NULL),

        __ATTR(max_user_freq, S_IRUGO | S_IWUSR, rtc_sysfs_show_max_user_freq,

                        rtc_sysfs_set_max_user_freq),

        { },

};

static ssize_t

rtc_sysfs_show_wakealarm(struct device *dev, struct device_attribute *attr,

                char *buf)

{

        ssize_t retval;

        unsigned long alarm;

        struct rtc_wkalrm alm;

        /* Don't show disabled alarms; but the RTC could leave the

         * alarm enabled after it's already triggered.  Alarms are

         * conceptually one-shot, even though some common hardware

         * (PCs) doesn't actually work that way.

         *

         * REVISIT maybe we should require RTC implementations to

         * disable the RTC alarm after it triggers, for uniformity.

         */

        retval = rtc_read_alarm(to_rtc_device(dev), &alm);

        if (retval == 0 && alm.enabled) {

                rtc_tm_to_time(&alm.time, &alarm);

                retval = sprintf(buf, "%lu\n", alarm);

        }

        return retval;

}

static ssize_t

rtc_sysfs_set_wakealarm(struct device *dev, struct device_attribute *attr,

                const char *buf, size_t n)

{

        ssize_t retval;

        unsigned long now, alarm;

        struct rtc_wkalrm alm;

        struct rtc_device *rtc = to_rtc_device(dev);

        /* Only request alarms that trigger in the future.  Disable them

         * by writing another time, e.g. 0 meaning Jan 1 1970 UTC.

         */

        retval = rtc_read_time(rtc, &alm.time);

        if (retval < 0)

                return retval;

        rtc_tm_to_time(&alm.time, &now);

        alarm = simple_strtoul(buf, NULL, 0);

        if (alarm > now) {

                /* Avoid accidentally clobbering active alarms; we can't

                 * entirely prevent that here, without even the minimal

                 * locking from the /dev/rtcN api.

                 */

                retval = rtc_read_alarm(rtc, &alm);

                if (retval < 0)

                        return retval;

                if (alm.enabled)

                        return -EBUSY;

                alm.enabled = 1;

        } else {

                alm.enabled = 0;

                /* Provide a valid future alarm time.  Linux isn't EFI,

                 * this time won't be ignored when disabling the alarm.

                 */

                alarm = now + 300;

        }

        rtc_time_to_tm(alarm, &alm.time);

        retval = rtc_set_alarm(rtc, &alm);

        return (retval < 0) ? retval : n;

}

static DEVICE_ATTR(wakealarm, S_IRUGO | S_IWUSR,

                rtc_sysfs_show_wakealarm, rtc_sysfs_set_wakealarm);

/* The reason to trigger an alarm with no process watching it (via sysfs)

 * is its side effect:  waking from a system state like suspend-to-RAM or

 * suspend-to-disk.  So: no attribute unless that side effect is possible.

 * (Userspace may disable that mechanism later.)

 */

static inline int rtc_does_wakealarm(struct rtc_device *rtc)

{

        if (!device_can_wakeup(rtc->dev.parent))

                return 0;

        return rtc->ops->set_alarm != NULL;

}

void rtc_sysfs_add_device(struct rtc_device *rtc)

{

        int err;

        /* not all RTCs support both alarms and wakeup */

        if (!rtc_does_wakealarm(rtc))

                return;

        err = device_create_file(&rtc->dev, &dev_attr_wakealarm);

        if (err)

                dev_err(rtc->dev.parent,

                        "failed to create alarm attribute, %d\n", err);

}

void rtc_sysfs_del_device(struct rtc_device *rtc)

{

        /* REVISIT did we add it successfully? */

        if (rtc_does_wakealarm(rtc))

                device_remove_file(&rtc->dev, &dev_attr_wakealarm);

}

void __init rtc_sysfs_init(struct class *rtc_class)

{

        rtc_class->dev_attrs = rtc_attrs;

}