[beagleboard] RTC not recognized in Angstrom 2.6.29 kernel

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1

Hi all,

I am using Beagleboard Rev C4. I am using Angstrom 2.6.29 kernel. The
u-boot is corresponding to the 2.6.29 kernel......

When I do hwclock, the message is "hwclock: can't open '/dev/misc/
rtc': No such file or directory"

I would like to use the time setting from the RTC........Even when the
OS is booting, I dont find any message as "twl4030_rtc twl4030_rtc:
Enabling TWL4030-RTC."

Someone please help me solve the issue........

Thanks,
Ramasamy Gopalan.

2

Hi,

When I booted the OS after posting the below message, for some reason,
it has recognised the RTC.......I am able to see the /dev/rtc folder
now, whereas previously I was not able to see it.......

And I also do not get the error message when I do hwclock now.......

But I am not able to get the current date and time properly......It
gives some weird date and time.........

Please help me.......

Thanks,
Ramasamy Gopalan.

3

Hi all,

When I do dmesg, I see the following:

root@beagleboard:~# dmesg | grep rtc
[ 405.761993] rtc-ds1307: probe of 2-0068 failed with error -5
[ 406.548675] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
[ 411.466735] twl4030_rtc twl4030_rtc: rtc core: registered
twl4030_rtc as rtc0

Thanks,
Ramasamy Gopalan.

4

Assuming you mean real time clock, I don’t think anything but the upcoming xM has an RTC onboard. Are you using an expansion board?

Hope this helps.
– @

5

The RTC is built into the TPS65950 on the Rev C4 board. It is exactly the same on the -xM board.

Gerald

6

Oh, thanks, I didn’t know that.

– @

7

Hi!

I think messages about ds1307 refer to some expansion board (I’m not sure but it seems to be Zippy), so if you don’t have one this error is OK.

Next: RTC is build in TPS65950 (power chip on BB). If you did not set up the date properly so what date do you expect to see? Beagleboard does not have any battery for RTC backup so the date and time just has to be weird after the power up.

regards,
Max

2010/5/19 ramasamygopalan <ramasamygopalan@gmail.com>

8

Hi!

I think messages about ds1307 refer to some expansion board (I'm not sure but it seems to be Zippy), so if you don't have one this error is OK.

Next: RTC is build in TPS65950 (power chip on BB). If you did not set up the date properly so what date do you expect to see? Beagleboard does not have any battery for RTC backup so the date and time just has to be weird after the power up.

On C3 and up there are hookup points for a battery, check the beagle manual.

regards,

Koen

9

> Next: RTC is build in TPS65950 (power chip on BB). If you did not set up

the date

> properly so what date do you expect to see? Beagleboard does not have

any battery

> for RTC backup so the date and time just has to be weird after the power

up.

On C3 and up there are hookup points for a battery, check the beagle

manual.

If the RTC clock isn’t valid, I think you normally would get a timestamp
running from the kernel_build_time plus the time since power up => It’s not
totally weird :slight_smile:

Best regards
  Søren