I've had a problem for weeks with a development board I have used in the past on the Original RaspberryPi. The expansion board has two spi devices connected, a CAN Bus controller (MCP2515) and a Real Time Clock chip DS3234. On the old RPi everything works great with two devices in:
/sys/bus/spi/devices pi@can-rtc:~$ cat /sys/bus/spi/devices/spi0.0/modalias spi:mcp2515 pi@can-rtc:~$ cat /sys/bus/spi/devices/spi0.1/modalias spi:ds3234 This output is exactly the same on the RPi-2 but the RPi-2 finds the RTC time invalid: sudo hwclock -r hwclock: The Hardware Clock registers contain values that are either invalid (e.g. 50th day of month) or beyond. The CAN Bus Controller does work on both versions of the RPi, it's just the RTC that has a problem. If connect up the Ethernet interface to get the correct time, from the network, I can write it to the device with "hwclock -w". Then remove the expansion board and power it up on the original RPi and it's got the correct time which is sets as the system time. If I now remove it from the original RPi and connect to RPi-2 it can't read a valid time. but it all seems the same. cat /sys/bus/spi/devices/spi0.1/rtc/rtc0/name ds3234 In both cases I've compiled the ds3234 and mcp2515 drivers into the kernel. In the original RPi the board file is edited to add the two devices but in the RPi-2 a hardware overlay file is added. Like I say everything appears to be exactly the same in both cases. Just the result is totally different. Can anybody explain why there should be a difference? The GPIO headers in both versions of the RPi are the same for the first set of pins. Original RPi kenel - 3.15.5 RPi-2 kernel - 3.18.8 _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies