at91sam9_rtt.c
2.02 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
/*
* (C) Copyright 2010
* Reinhard Meyer, reinhard.meyer@emk-elektronik.de
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* Date & Time support for the internal Real-time Timer
* of AT91SAM9260 and compatibles.
* Compatible with the LinuX rtc driver workaround:
* The RTT cannot be written to, but only reset.
* The actual time is the sum of RTT and one of
* the four GPBR registers.
*
* The at91sam9260 has 4 GPBR (0-3).
* For their typical use see at91_gpbr.h !
*
* make sure u-boot and kernel use the same GPBR !
*/
#include <common.h>
#include <command.h>
#include <rtc.h>
#include <asm/io.h>
#include <linux/errno.h>
#include <asm/arch/hardware.h>
#include <asm/arch/at91_rtt.h>
#include <asm/arch/at91_gpbr.h>
#if defined(CONFIG_CMD_DATE)
int rtc_get (struct rtc_time *tmp)
{
at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
ulong tim;
ulong tim2;
ulong off;
do {
tim = readl(&rtt->vr);
tim2 = readl(&rtt->vr);
} while (tim!=tim2);
off = readl(&gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
/* off==0 means time is invalid, but we ignore that */
rtc_to_tm(tim+off, tmp);
return 0;
}
int rtc_set (struct rtc_time *tmp)
{
at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
ulong tim;
tim = rtc_mktime(tmp);
/* clear alarm, set prescaler to 32768, clear counter */
writel(32768+AT91_RTT_RTTRST, &rtt->mr);
writel(~0, &rtt->ar);
writel(tim, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
/* wait for counter clear to happen, takes less than a 1/32768th second */
while (readl(&rtt->vr) != 0)
;
return 0;
}
void rtc_reset (void)
{
at91_rtt_t *rtt = (at91_rtt_t *) ATMEL_BASE_RTT;
at91_gpbr_t *gpbr = (at91_gpbr_t *) ATMEL_BASE_GPBR;
/* clear alarm, set prescaler to 32768, clear counter */
writel(32768+AT91_RTT_RTTRST, &rtt->mr);
writel(~0, &rtt->ar);
writel(0, &gpbr->reg[AT91_GPBR_INDEX_TIMEOFF]);
/* wait for counter clear to happen, takes less than a 1/32768th second */
while (readl(&rtt->vr) != 0)
;
}
#endif