linux-imx

/*

 * rtc-efi: RTC Class Driver for EFI-based systems

 *

 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.

 *

 * Author: dann frazier <dannf@dannf.org>

 * Based on efirtc.c by Stephane Eranian

 *

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

 *  under  the terms of  the GNU General  Public License as published by the

 *  Free Software Foundation;  either version 2 of the  License, or (at your

 *  option) any later version.

 *

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/stringify.h>

#include <linux/time.h>

#include <linux/platform_device.h>

#include <linux/rtc.h>

#include <linux/efi.h>

​

#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)

​

/*

 * returns day of the year [0-365]

 */

static inline int

compute_yday(efi_time_t *eft)

{

    /* efi_time_t.month is in the [1-12] so, we need -1 */

    return rtc_year_days(eft->day, eft->month - 1, eft->year);

}

​

/*

 * returns day of the week [0-6] 0=Sunday

 */

static int

compute_wday(efi_time_t *eft, int yday)

{

    int ndays = eft->year * (365 % 7)

            + (eft->year - 1) / 4

            - (eft->year - 1) / 100

            + (eft->year - 1) / 400

            + yday;

​

    /*

     * 1/1/0000 may or may not have been a Sunday (if it ever existed at

     * all) but assuming it was makes this calculation work correctly.

     */

    return ndays % 7;

}

​

static void

convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)

{

    eft->year   = wtime->tm_year + 1900;

    eft->month  = wtime->tm_mon + 1;

    eft->day    = wtime->tm_mday;

    eft->hour   = wtime->tm_hour;