[PATCH linux] mach-aspeed: Add Zaius BMC PHY reset

[Xo Wang]

Hi Joel,

On Mon, Oct 24, 2016 at 9:18 PM, Joel Stanley <joel at jms.id.au> wrote:
> Hi Xo,
>
> On Fri, Oct 21, 2016 at 3:27 PM, Joel Stanley <joel at jms.id.au> wrote:
>> On Fri, Oct 21, 2016 at 9:26 AM, Xo Wang <xow at google.com> wrote:
>>> The Broadcom PHY for the Zaius BMC requires a hard reset after RGMII
>>> clocks are enabled. This asserts the reset in case it wasn't performed
>>> in U-Boot.
>
>> I'm not sure how we would handle this properly if we were to submit it
>> upstream. We can carry it for now though.
>
> I came across this thread on lkml: https://patchwork.ozlabs.org/patch/685741/
>
> It has some suggestions for now to do a hard reset of the IP on boot
> using GPIOs, which might be an upstreamable solution for your issue.
>
> Cheers,
>
> Joel

I was hoping to wiggle out of needing this PHY reset if it can instead
happen in U-Boot, but now I'm thinking that would be an irritating
(and unexpected) dependency to have.

The discussion and proposed code there make sense to me. The
discussion for the general libphy driver reset looks like it has some
nuances yet to be ironed out:
https://patchwork.ozlabs.org/patch/623651/

Do you think the path of least controversy would be to port the
Freescale MAC patch to the Broadcom PHY driver?

cheers
xo