Hi Jean,
On 24.06.2016 15:38, Jean Delvare wrote:
On ven., 2016-06-24 at 13:57 +0200, Stefan Roese wrote:
Hi,
I'm currently trying to use the SMBus on a congatec BayTrail board.
This works just fine when booting via the original BIOS. But when I
boot into Linux using U-Boot as bootloader, I get the following
errors:
[ 81.877121] i801_smbus 0000:00:1f.3: Transaction timeout
[ 81.879228] i801_smbus 0000:00:1f.3: Failed terminating the transaction
[ 81.879320] i801_smbus 0000:00:1f.3: SMBus is busy, can't use it!
[ 81.879373] i801_smbus 0000:00:1f.3: SMBus is busy, can't use it!
[ 81.879421] i801_smbus 0000:00:1f.3: SMBus is busy, can't use it!
[ 81.879496] i801_smbus 0000:00:1f.3: SMBus is busy, can't use it!
...
I checked with an oscilloscope and the SMBus clock is not toggling
at all in this case. My feeling is, that some basic setup is missing
in this non-BIOS case. Like some clock enabling. Does anyone of you
have some idea here?
No immediate idea, sorry. Two ideas:
* Is this problem specific to Baytrail systems, or does i2c-i801 fail on
all U-Boot systems?
I only have BayTrail systems right now.
* Did you try comparing the PCI configuration space of the SMBus device
between original BIOS boot (working) and U-Boot boot (not working)?
The issue seems to be solved just a few minutes ago. As it seems
a pin-mux configuration was missing for the SMBus pins. Now the bus
can be scanned in Linux without any issues.
Thanks,
Stefan
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