[U-Boot] [PATCH v2 2/5] net: sun8i_emac: Support RX/TX delay chains

[Simon Glass]

Hi Joe,

On 7 December 2017 at 11:45, Joe Hershberger <joe.hershberger at gmail.com> wrote:
>
> On Wed, Dec 6, 2017 at 8:35 PM, Chen-Yu Tsai <wens at csie.org> wrote:
> > On Thu, Dec 7, 2017 at 4:20 AM, Joe Hershberger
> > <joe.hershberger at gmail.com> wrote:
> >> On Tue, Dec 5, 2017 at 8:34 PM, Chen-Yu Tsai <wens at csie.org> wrote:
> >>> On Wed, Dec 6, 2017 at 4:50 AM, Joe Hershberger <joe.hershberger at ni.com> wrote:
> >>>> On Fri, Nov 24, 2017 at 11:08 PM, Chen-Yu Tsai <wens at csie.org> wrote:
> >>>>> The EMAC syscon has configurable RX/TX delay chains for use with RGMII
> >>>>> PHYs.
> >>>>>
> >>>>> This adds support for configuring them via device tree properties. The
> >>>>> property names and format were defined in Linux's dwmac-sun8i binding
> >>>>> that was merged at one point.
> >>>>
> >>>> I'm not seeing this in doc/device-tree-bindings/net/
> >>>
> >>> See https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/net/dwmac-sun8i.txt
> >>>
> >>> The bindings have been restored as of v4.15-rc1.
> >>>
> >>> We are following DT bindings as defined in the Linux kernel. Deviation
> >>> is kept to a minimum, and eliminated if possible. We still need to
> >>> migrate the driver to the new bindings for the internal PHY bits.
> >>> But that bit might still be changed during the 4.15 release cycle.
> >>
> >> That's good, but we want to have the currently supported bindings
> >> copied into the U-Boot tree under doc/device-tree-bindings/net/.
> >> Please include a patch that adds the bindings that your driver is
> >> using.
> >
> > Looks like this is a new requirement. Or it wasn't really enforced
> > before. Doesn't this make U-boot prone to having diverging device
> > tree bindings? It has already happened with the regulator bindings,
> > specifically the "regulator-name" property.
> >
> > And by "currently supported", are you referring to what the driver
> > expects, and not what the end result, i.e. the accepted bindings
> > in Linux, should be? This driver is still in a state of catchup.
> > The driver supports a previously merged then reverted set of
> > bindings. These bindings were then brought back and updated for
> > Linux v4.15 (unreleased yet, so may still change, again). So which
> > set of bindings should I submit here?
> >
> > And the goal _is_ to migrate the driver to what Linux is using, so
> > we can share the device tree files.
>
> I believe the goal is to have them match the current state of the
> driver as supported in U-Boot, and a higher-level goal of keeping the
> bindings + driver in sync with Linux for sharing.

Yes, they should match, and we should have the same binding file.

Also, please use dev_read_...() instead of fdtdec...() for all new
code since that supports live tree.

>
> Correct, Simon?
>
> Thanks,
> -Joe

Regards,
Simon