u-boot/drivers/rtc/davinci.c
Dario Binacchi c7c7c8db00 rtc: davinci: use unlock/lock mechanism
The RTC module contains a kicker mechanism to prevent any spurious
writes from changing the register values. To set the time, you must
first unlock the TC registers, update them and then lock.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210602203805.11494-6-dariobin@libero.it
2021-06-09 22:23:44 +05:30

128 lines
3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2011 DENX Software Engineering GmbH
* Heiko Schocher <hs@denx.de>
*/
#include <common.h>
#include <command.h>
#include <log.h>
#include <rtc.h>
#include <asm/io.h>
#include <asm/davinci_rtc.h>
#include <asm/arch/hardware.h>
#include <linux/delay.h>
#if !defined(RTC_BASE) && defined(DAVINCI_RTC_BASE)
#define RTC_BASE DAVINCI_RTC_BASE
#endif
static void davinci_rtc_lock(struct davinci_rtc *rtc)
{
writel(0, &rtc->kick0r);
writel(0, &rtc->kick1r);
}
static void davinci_rtc_unlock(struct davinci_rtc *rtc)
{
writel(RTC_KICK0R_WE, &rtc->kick0r);
writel(RTC_KICK1R_WE, &rtc->kick1r);
}
static int davinci_rtc_wait_not_busy(struct davinci_rtc *rtc)
{
int count;
u8 status;
status = readb(&rtc->status);
if ((status & RTC_STATE_RUN) != RTC_STATE_RUN) {
printf("RTC doesn't run\n");
return -1;
}
/* BUSY may stay active for 1/32768 second (~30 usec) */
for (count = 0; count < 50; count++) {
if (!(status & RTC_STATE_BUSY))
break;
udelay(1);
status = readb(&rtc->status);
}
/* now we have ~15 usec to read/write various registers */
return 0;
}
int rtc_get(struct rtc_time *tmp)
{
struct davinci_rtc *rtc = (struct davinci_rtc *)RTC_BASE;
unsigned long sec, min, hour, mday, wday, mon_cent, year;
int ret;
ret = davinci_rtc_wait_not_busy(rtc);
if (ret)
return ret;
sec = readb(&rtc->second);
min = readb(&rtc->minutes);
hour = readb(&rtc->hours);
mday = readb(&rtc->day);
wday = readb(&rtc->dotw);
mon_cent = readb(&rtc->month);
year = readb(&rtc->year);
debug("Get RTC year: %02lx mon/cent: %02lx mday: %02lx wday: %02lx "
"hr: %02lx min: %02lx sec: %02lx\n",
year, mon_cent, mday, wday,
hour, min, sec);
tmp->tm_sec = bcd2bin(sec & 0x7F);
tmp->tm_min = bcd2bin(min & 0x7F);
tmp->tm_hour = bcd2bin(hour & 0x3F);
tmp->tm_mday = bcd2bin(mday & 0x3F);
tmp->tm_mon = bcd2bin(mon_cent & 0x1F);
tmp->tm_year = bcd2bin(year) + 2000;
tmp->tm_wday = bcd2bin(wday & 0x07);
tmp->tm_yday = 0;
tmp->tm_isdst = 0;
debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return 0;
}
int rtc_set(struct rtc_time *tmp)
{
struct davinci_rtc *rtc = (struct davinci_rtc *)RTC_BASE;
int ret;
ret = davinci_rtc_wait_not_busy(rtc);
if (ret)
return ret;
davinci_rtc_unlock(rtc);
writeb(bin2bcd(tmp->tm_year % 100), &rtc->year);
writeb(bin2bcd(tmp->tm_mon), &rtc->month);
writeb(bin2bcd(tmp->tm_wday), &rtc->dotw);
writeb(bin2bcd(tmp->tm_mday), &rtc->day);
writeb(bin2bcd(tmp->tm_hour), &rtc->hours);
writeb(bin2bcd(tmp->tm_min), &rtc->minutes);
writeb(bin2bcd(tmp->tm_sec), &rtc->second);
davinci_rtc_lock(rtc);
debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
return 0;
}
void rtc_reset(void)
{
struct davinci_rtc *rtc = (struct davinci_rtc *)RTC_BASE;
/* run RTC counter */
writeb(0x01, &rtc->ctrl);
}