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git.ipfire.org Git - thirdparty/u-boot.git/blob - drivers/rtc/at91sam9_rtt.c
3 * Reinhard Meyer, reinhard.meyer@emk-elektronik.de
5 * SPDX-License-Identifier: GPL-2.0+
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.
16 * The at91sam9260 has 4 GPBR (0-3).
17 * For their typical use see at91_gpbr.h !
19 * make sure u-boot and kernel use the same GPBR !
26 #include <asm/errno.h>
27 #include <asm/arch/hardware.h>
28 #include <asm/arch/at91_rtt.h>
29 #include <asm/arch/at91_gpbr.h>
31 #if defined(CONFIG_CMD_DATE)
33 int rtc_get (struct rtc_time
*tmp
)
35 at91_rtt_t
*rtt
= (at91_rtt_t
*) ATMEL_BASE_RTT
;
36 at91_gpbr_t
*gpbr
= (at91_gpbr_t
*) ATMEL_BASE_GPBR
;
42 tim
= readl(&rtt
->vr
);
43 tim2
= readl(&rtt
->vr
);
45 off
= readl(&gpbr
->reg
[AT91_GPBR_INDEX_TIMEOFF
]);
46 /* off==0 means time is invalid, but we ignore that */
51 int rtc_set (struct rtc_time
*tmp
)
53 at91_rtt_t
*rtt
= (at91_rtt_t
*) ATMEL_BASE_RTT
;
54 at91_gpbr_t
*gpbr
= (at91_gpbr_t
*) ATMEL_BASE_GPBR
;
57 tim
= mktime (tmp
->tm_year
, tmp
->tm_mon
, tmp
->tm_mday
,
58 tmp
->tm_hour
, tmp
->tm_min
, tmp
->tm_sec
);
60 /* clear alarm, set prescaler to 32768, clear counter */
61 writel(32768+AT91_RTT_RTTRST
, &rtt
->mr
);
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)
72 at91_rtt_t
*rtt
= (at91_rtt_t
*) ATMEL_BASE_RTT
;
73 at91_gpbr_t
*gpbr
= (at91_gpbr_t
*) ATMEL_BASE_GPBR
;
75 /* clear alarm, set prescaler to 32768, clear counter */
76 writel(32768+AT91_RTT_RTTRST
, &rtt
->mr
);
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)