[PATCH linux dev-4.10] drivers/fsi: Break and set pin states on GPIO master remove

Jeremy Kerr jk at ozlabs.org
Thu Jun 8 20:00:35 AEST 2017

Hi Alistair & Chris,

>> The pins are set here mainly for the benefit of the Cronus debug 
>> tools.   Its common practice in test and bringup labs to switch back and 
>> forth between BMC and FSP-2 with Cronus to access the host processor 
>> CFAMs over FSI.  Without the remove pin state changes Cronus cannot access.
> As far as I know you have to run "systemctl start fsi-disable.service"
> to switch over to Cronus mode. I think Jeremy's point is that it
> should be that service which explicitly sets up the hardware in a
> suitable mode rather than relying on side-effects from removing the
> kernel driver.

Yep, spot on.

Also, those side-effects might not be how the GPIOs need to configured
for the next usage of the FSI bus (which could be Cronus, but could also
be any other tool). So, let those tools handle the init correctly,
rather than the kernel making a guess at it.



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