[PATCH linux] ARM: dts: aspeed: zaius: Enable NC-SI mux

Xo Wang xow at google.com
Wed Mar 8 08:31:24 AEDT 2017

On Tue, Mar 7, 2017 at 1:21 PM, Rick Altherr <raltherr at google.com> wrote:
> I don't believe it currently does.  I'm concerned with whether U-Boot
> or Linux is expected to configure the NC-SI muxes.
> On Tue, Mar 7, 2017 at 1:19 PM, Xo Wang <xow at google.com> wrote:
>> On Tue, Mar 7, 2017 at 1:13 PM, Rick Altherr <raltherr at google.com> wrote:
>>> Why is Linux doing this instead of U-Boot?
>> Does our U-Boot understand Aspeed GPIO in the device tree? If it does,
>> then it makes more sense for U-Boot to consume and set these pin
>> assignments.
>> xo

I would think U-Boot is expected to, since that provides the option of
netbooting from the NC-SI adapter in U-Boot.

In addition, the Linux ftgmac100 driver can't yet handle the NC-SI mux
changing dynamically (https://github.com/openbmc/openbmc/issues/979).
So for now the mux must be enabled and selected prior to that driver
probing. This is the only reason why this assignment exists as a Linux
gpio-hog: it is set prior to any other driver being probed.


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