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Reinhard Meyerc7260d12010-07-27 16:22:09 +02001/*
2 * (C) Copyright 2010
3 * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
4 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02005 * SPDX-License-Identifier: GPL-2.0+
Reinhard Meyerc7260d12010-07-27 16:22:09 +02006 */
7
8/*
9 * Date & Time support for the internal Real-time Timer
10 * of AT91SAM9260 and compatibles.
11 * Compatible with the LinuX rtc driver workaround:
12 * The RTT cannot be written to, but only reset.
13 * The actual time is the sum of RTT and one of
14 * the four GPBR registers.
15 *
16 * The at91sam9260 has 4 GPBR (0-3).
17 * For their typical use see at91_gpbr.h !
18 *
19 * make sure u-boot and kernel use the same GPBR !
20 */
21
22#include <common.h>
23#include <command.h>
24#include <rtc.h>
Reinhard Meyer86592f62010-11-07 13:26:14 +010025#include <asm/io.h>
Reinhard Meyerc7260d12010-07-27 16:22:09 +020026#include <asm/errno.h>
27#include <asm/arch/hardware.h>
Reinhard Meyerc7260d12010-07-27 16:22:09 +020028#include <asm/arch/at91_rtt.h>
29#include <asm/arch/at91_gpbr.h>
30
31#if defined(CONFIG_CMD_DATE)
32
33int rtc_get (struct rtc_time *tmp)
34{
Reinhard Meyer372f2782010-11-03 15:47:20 +010035 at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
36 at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
Reinhard Meyerc7260d12010-07-27 16:22:09 +020037 ulong tim;
38 ulong tim2;
39 ulong off;
40
41 do {
42 tim = readl(&rtt->vr);
43 tim2 = readl(&rtt->vr);
44 } while (tim!=tim2);
45 off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
46 /* off==0 means time is invalid, but we ignore that */
47 to_tm (tim+off, tmp);
48 return 0;
49}
50
51int rtc_set (struct rtc_time *tmp)
52{
Reinhard Meyer372f2782010-11-03 15:47:20 +010053 at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
54 at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
Reinhard Meyerc7260d12010-07-27 16:22:09 +020055 ulong tim;
56
57 tim = mktime (tmp->tm_year, tmp->tm_mon, tmp->tm_mday,
58 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
59
60 /* clear alarm, set prescaler to 32768, clear counter */
61 writel(32768+AT91_RTT_RTTRST, &rtt->mr);
62 writel(~0, &rtt->ar);
63 writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
64 /* wait for counter clear to happen, takes less than a 1/32768th second */
65 while (readl(&rtt->vr) != 0)
66 ;
67 return 0;
68}
69
70void rtc_reset (void)
71{
Reinhard Meyer372f2782010-11-03 15:47:20 +010072 at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
73 at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
Reinhard Meyerc7260d12010-07-27 16:22:09 +020074
75 /* clear alarm, set prescaler to 32768, clear counter */
76 writel(32768+AT91_RTT_RTTRST, &rtt->mr);
77 writel(~0, &rtt->ar);
78 writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
79 /* wait for counter clear to happen, takes less than a 1/32768th second */
80 while (readl(&rtt->vr) != 0)
81 ;
82}
83
84#endif