i.MX ProcessorsのトピックRe: The problem of RTC on Android6.0

The problem of RTC on Android6.0

pengxingwei — Wed, 18 Apr 2018 00:36:28 GMT

Hi,

My platform is Android6.0(the kernel version is linux 4.1.15), the rtc is pcf8563, so the driver is rtc-pcf8563, but I found a problem that the time can't save and the time is 1970-1-1 8:00 after the sytem startup every time, the start log as follow about pcf8563:

rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
rtc-pcf8563 2-0051: rtc core: registered rtc-pcf8563 as rtc0

rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
rtc-pcf8563 2-0051: hctosys: unable to read the hardware clock

how to slove the problem? Thanks !

Re: The problem of RTC on Android6.0

weidong_sun — Wed, 18 Apr 2018 02:44:18 GMT

Hello xingwei,

Since you use external RTC chip, It means there are 2 RTCs in you system, another is RTC in CPU.

According to your description, I feel your system is using SRTC in CPU, if you don't connect Battery for the SRTC, after shut down and startup again, timer will be reset.

So please check which RTC chip is using in your system.

Have a nice day!

Best Regards,

weidong

Re: The problem of RTC on Android6.0

pengxingwei — Wed, 18 Apr 2018 02:56:23 GMT

Hello Wigros,

Thanks for your reply. I had disabled the snvs rtc in my kernel configuration file ,and the kernel log about rtc is as follow:

So ,there is only pcf8563 rtc in my system.

Thanks!

Re: The problem of RTC on Android6.0

pengxingwei — Wed, 18 Apr 2018 05:49:17 GMT

Hello Wigros,

Thanks for your reply. I had disabled the snvs rtc in my kernel configuration file ,and the kernel log about rtc is as follow:

root@sabresd_6dq:/ # dmesg | grep -i rtc
[    3.752979] rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
[    3.760676] rtc-pcf8563 2-0051: rtc core: registered rtc-pcf8563 as rtc0
[    6.454430] rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
[    6.461913] rtc-pcf8563 2-0051: hctosys: unable to read the hardware clock
root@sabresd_6dq:/ #

So ,there is only pcf8563 rtc in my system.

Thanks!