[U-Boot] am33xx board with no external RTC crystal issue

Belisko Marek marek.belisko at gmail.com
Mon Oct 29 11:13:18 UTC 2018


Hi,

I'm working on custome am33xx based HW which have no external 32KHz
crystal. Anyway I want to use bootcount feature. I was trying to use
internal PRCM CLK_32KHZ clock as source for RTCSS but still when want
to read RTC registers I get data abort.

I adapted this method :

static void rtc32k_enable(void)
 {
        struct davinci_rtc *rtc = (struct davinci_rtc *)RTC_BASE;

        /*
         * Unlock the RTC's registers.  For more details please see the
         * RTC_SS section of the TRM.  In order to unlock we need to
@@ -287,9 +288,8 @@ static void rtc32k_enable(void)
        writel(RTC_KICK1R_WE, &rtc->kick1r);

        /* Enable the RTC 32K OSC by setting bits 3 and 6. */
-       writel((1 << 3) | (1 << 6), &rtc->osc);
+       writel((1 << 6), &rtc->osc);
 }

to not use external crystal 32KHz clock but internal. Anyway when
doing that board just hangs and thats it. Any ideas or suggestions? It
is even possible to have something like that? I just seen that
include/configs/siemens-am33x-common.h (using also am335x cpu without
external 32KHz crystal) storing bootcount to env. Thanks a lot for any
pointers.

BR,

marek
-- 
as simple and primitive as possible
-------------------------------------------------
Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
twitter: #opennandra
web: http://open-nandra.com


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