Re: [PATCH v2 0/2] Add macb support for SiFive FU540-C000

[Yash Shah <yash.shah@sifive.com>]

On Mon, Jun 17, 2019 at 3:58 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> On Mon, 17 Jun 2019, Yash Shah wrote:
>
> > On Mon, Jun 17, 2019 at 3:28 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
> >
> > > On Mon, 17 Jun 2019, Andreas Schwab wrote:
> > >
> > > > On Jun 17 2019, Yash Shah <yash.shah@sifive.com> wrote:
> > > >
> > > > > - Add "MACB_SIFIVE_FU540" in Kconfig to support SiFive FU540 in macb
> > > > >   driver. This is needed because on FU540, the macb driver depends on
> > > > >   SiFive GPIO driver.
> > > >
> > > > This of course requires that the GPIO driver is upstreamed first.
> > >
> > > What's the impact of enabling CONFIG_MACB_SIFIVE_FU540 when the GPIO
> > > driver isn't present?  (After modifying the Kconfig "depends" line
> > > appropriately.)
> > >
> > > Looks to me that it shouldn't have an impact unless the DT string is
> > > present, and even then, the impact might simply be that the MACB driver
> > > may not work?
> >
> > Yes, there won't be an impact other than MACB driver not working.
>
> OK.  In that case, there doesn't seem much point to adding the Kconfig
> option.  Could you please post a new version without it?

Sure, will do that.

>
> > In any case, without GPIO driver, PHY won't get reset and the network
> > interface won't come up.
>
> Naturally, in the medium term, we want Linux to handle the reset.  But if
> there's no GPIO driver present, and the bootloader handles the PHY reset
> before the kernel starts, would the network driver work in that case?

Yes, if bootloader handles the PHY reset then the network driver will
work in that case.
I will post a new version without the GPIO driver dependency.

>
>
> - Paul