LXR uboot/drivers/rtc/at91sam9

   1/*
   2 * (C) Copyright 2010
   3 * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 */
  23
  24/*
  25 * Date & Time support for the internal Real-time Timer
  26 * of AT91SAM9260 and compatibles.
  27 * Compatible with the LinuX rtc driver workaround:
  28 * The RTT cannot be written to, but only reset.
  29 * The actual time is the sum of RTT and one of
  30 * the four GPBR registers.
  31 *
  32 * The at91sam9260 has 4 GPBR (0-3).
  33 * For their typical use see at91_gpbr.h !
  34 *
  35 * make sure u-boot and kernel use the same GPBR !
  36 */
  37
  38#include <common.h>
  39#include <command.h>
  40#include <rtc.h>
  41#include <asm/io.h>
  42#include <asm/errno.h>
  43#include <asm/arch/hardware.h>
  44#include <asm/arch/at91_rtt.h>
  45#include <asm/arch/at91_gpbr.h>
  46
  47#if defined(CONFIG_CMD_DATE)
  48
  49int rtc_get (struct rtc_time *tmp)
  50{
  51        at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
  52        at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
  53        ulong tim;
  54        ulong tim2;
  55        ulong off;
  56
  57        do {
  58                tim = readl(&rtt->vr);
  59                tim2 = readl(&rtt->vr);
  60        } while (tim!=tim2);
  61        off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
  62        /* off==0 means time is invalid, but we ignore that */
  63        to_tm (tim+off, tmp);
  64        return 0;
  65}
  66
  67int rtc_set (struct rtc_time *tmp)
  68{
  69        at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
  70        at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
  71        ulong tim;
  72
  73        tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
  74                      tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  75
  76        /* clear alarm, set prescaler to 32768, clear counter */
  77        writel(32768+AT91_RTT_RTTRST, &rtt->mr);
  78        writel(~0, &rtt->ar);
  79        writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
  80        /* wait for counter clear to happen, takes less than a 1/32768th second */
  81        while (readl(&rtt->vr) != 0)
  82                ;
  83        return 0;
  84}
  85
  86void rtc_reset (void)
  87{
  88        at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
  89        at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
  90
  91        /* clear alarm, set prescaler to 32768, clear counter */
  92        writel(32768+AT91_RTT_RTTRST, &rtt->mr);
  93        writel(~0, &rtt->ar);
  94        writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
  95        /* wait for counter clear to happen, takes less than a 1/32768th second */
  96        while (readl(&rtt->vr) != 0)
  97                ;
  98}
  99
 100#endif
 101