[U-Boot] [PATCH u-boot 1/2] net: phy: Add support for accessing MMD PHY registers

[Joe Hershberger]

On Tue, Jan 22, 2019 at 4:54 PM Carlo Caione <ccaione at baylibre.com> wrote:
>
> On 22/01/19 22:21, Joe Hershberger wrote:
> >On Wed, Jan 16, 2019 at 12:06 PM Carlo Caione <ccaione at baylibre.com> wrote:
> >>
> >> Two new helper functions (phy_read_mmd() and phy_write_mmd()) are added
> >> to allow access to the MMD PHY registers.
> >>
> >> The MMD PHY registers can be accessed by two means:
> >>
> >> 1. Using two new MMD access function hooks in the PHY driver. These
> >> functions can be implemented when the PHY driver does not support the
> >> standard IEEE Compatible clause 45 access mechanism described in clause
> >> 22 or if the PHY uses its own non-standard access mechanism.
> >>
> >> 2. The standard clause 45 access extensions to the MMD registers through
> >> the indirection registers (clause 22) in all the other cases.
> >>
> >> Signed-off-by: Carlo Caione <ccaione at baylibre.com>
> >
> >This seems like a duplicate of https://patchwork.ozlabs.org/patch/1015782/
>
> Well, I should have looked better. Interestingly I was going to use my
> patch to fix the exact same issue on a different PHY.
>
> The problem I see with that patch is that it is assuming that all the
> PHY devices support clause 45 access extension using the clause 22
> registers. This is not always true (see for example [0]). That's why I
> added two new hooks in the PHY driver.

Ah, I didn't realize there were other ways to access it.

> On a side note looking at that patch it seems that 'addr' (documented as
> the PHY address in the same patch) is being passed to 'phy_write' where
> we should have the 'devad' parameter instead (MDIO_DEVAD_NONE)?

That is peculiar... Vlad, that wasn't your intent, was it?

> >The command patch should probably be adapted to use that.
>
> Let me know if you think it is valuable still to add the two hooks on
> top of that patch.

If we have to override the access then probably so. Maybe it would
make more sense to have a v2 from you that removes the duplicate code
from the ti phy driver and then have Vlad's smartEEE patch be rebased
on that.

I have not yet pushed Vlad's patches so we have an opportunity to do
it more cleanly potentially.

Thoughts from each of you?

> Thanks,
>
> [0] https://patchwork.ozlabs.org/patch/351634/
>
> --
> Carlo Caione
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