Also, I saw something really weird on my board with an uninitialized RTC:
On one of my boards with an uninitialized RTC, the RTC kernel message
("hctosys: unable to read the hardware clock") went away when I "hot
plugged" a USB<->serial converter into one of our USB ports on our board.
The USB HUB isn't connected to the I2C3 bus...
Does the USB hub device driver or the USB bus driver initialize the RTC if
it's uninitialized??? What could this be due to?
I'm running kernel 4.4.110-ti-r142 and debian 8.10 for the BB-X15..
Thanks!!
On Thursday, March 22, 2018 at 5:38:03 PM UTC-5, Jeff Andich wrote:
>
> I'm working with the RTC (MCP794110) at the moment, but on a "BB-X15 -
> like" custom board platform.
>
> I'm not sure I follow. your post.. What's the I2C tool? Are you talking
> about attaching the RTC to the BBB via the I2C tool or a problem with
> reading the RTC on the BBB? Pardon my ignorance but does the BBB come with
> an RTC (e.g. MCP794110) installed? The BB-X15 does..
>
> Did you enable the I2C bus the RTC is attached to in the dev. tree? On my
> platform, I had to enable the I2C bus (I2C3) in the dev. tree before the
> drivers for the RTC would load.
>
> Then with some "new" RTC's on some of my boards, but not all, I got
> "unable to read the hardware clock, I think, when the kernel is attempting
> to set the system clock from the hardware clock (see the following):
>
> ebian@BeagleBoard-X15:~$ dmesg|grep rtc
> [ 1.551522] rtc-ds1307 2-006f: rtc core: registered mcp7941x as rtc0
> [ 1.551652] rtc-ds1307 2-006f: 64 bytes nvram
> [ 1.554511] omap_rtc 48838000.rtc: rtc core: registered 48838000.rtc as
> rtc2
> [ 1.558261] palmas-rtc 48070000.i2c:tps659038@58:tps659038_rtc: rtc
> core: registered 48070000.i2c:tps659 as rtc1
> [ 1.997160] rtc-ds1307 2-006f: hctosys: unable to read the hardware
> clock.
>
> From what I've read on posts involving the RTC the following messages:
>
> 1) "unable to read the hardware clock" message and the
> 2) hwclock: ioctl(RTC_RD_TIME) to /dev/rtc to read the time failed:
> Invalid argument.
>
> are due to the RTC's time being not initialized or (?invalid?). I've been
> able to work-around this by setting the clock, but initially I get warning
> #2 when I initialize the clock with a valid date/time. I'm wondering if
> anyone can confirm if this is the correct fix for this scenario...
>
> Also, when PTC builds the BB-X15, and the BBB manufacture builds the
> BBB's (assuming BBB's have a RTC installed), do they ensure that the RTC
> is correctly initialized prior to shipping to the distributors ?
>
>
> On Wednesday, March 21, 2018 at 6:18:27 PM UTC-5, Graham wrote:
>>
>> Do you have pull-up resistors?
>>
>> --- Graham
>>
>> ==
>>
>>
>> On Monday, March 19, 2018 at 8:28:51 AM UTC-5, Paco Velasco wrote:
>>>
>>> When I connect the rtc it does not detect the 68 address (I2C Tool).
>>>
>>> I have test with 2 RTC diferent,and with the BBB I have no problem.
>>>
>>> Anybody knows what could be the problem? Thanks
>>>
>>>
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