[U-Boot] [PATCH 1/1] sunxi: Fix A20-OLinuXino-MICRO dts for LAN8710

[Maxime Ripard]

Hi,

On Wed, Sep 27, 2017 at 01:58:45PM +0000, Stefan Mavrodiev wrote:
> On 09/27/2017 04:19 PM, Maxime Ripard wrote:
> > Hi Stefan,
> > 
> > You should also put Jagan Teki as recipients.
> > 
> > On Wed, Sep 27, 2017 at 07:19:10AM +0000, Stefan Mavrodiev wrote:
> > >  From revision J the board uses new phy chip LAN8710. Compared
> > > with RTL8201, RA17 pin is TXERR. It has pullup which causes phy
> > > not to work. To fix this PA17 is muxed with GMAC function. This
> > > makes the pin output-low.
> > > 
> > > Signed-off-by: Stefan Mavrodiev <stefan at olimex.com>
> > > ---
> > >   arch/arm/dts/sun7i-a20-olinuxino-micro.dts | 9 ++++++++-
> > >   1 file changed, 8 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm/dts/sun7i-a20-olinuxino-micro.dts b/arch/arm/dts/sun7i-a20-olinuxino-micro.dts
> > > index 7e3006f..0bc5ea9 100644
> > > --- a/arch/arm/dts/sun7i-a20-olinuxino-micro.dts
> > > +++ b/arch/arm/dts/sun7i-a20-olinuxino-micro.dts
> > > @@ -95,7 +95,7 @@
> > >   &gmac {
> > >   	pinctrl-names = "default";
> > > -	pinctrl-0 = <&gmac_pins_mii_a>;
> > > +	pinctrl-0 = <&gmac_pins_mii_a>,<&gmac_txerr>;
> > >   	phy = <&phy1>;
> > >   	phy-mode = "mii";
> > >   	status = "okay";
> > > @@ -226,6 +226,13 @@
> > >   };
> > >   &pio {
> > > +	gmac_txerr: gmac_txerr at 0 {
> > > +		allwinner,pins = "PA17";
> > > +		allwinner,function = "gpio_out";
> > > +		allwinner,drive = <SUN4I_PINCTRL_10_MA>;
> > > +		allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
> > > +	};
> > > +
> > There's two issues with that patch:
> >    - In general we try to sync the DT with Linux when we can, and the
> >      patch that ended up in Linux wasn't this one.
>
> I'm little confused. If I sync the DT with the one from mainline linux,
> doesn't this counts as dangerous? I mean it will be the only one that is
> synced.
> This could corrupt building if sun7i-a20.dtsi is not synced for example.

I'm not sure what's dangerous about this. If the device tree is
working in Linux, it should be working in U-Boot, right?

> >    - And we don't have any pinctrl support in U-Boot, that patch will
> >      basically do nothing
> > 
> > The code that changes the muxing is here:
> > http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/gmac.c#l34
>
> Again, since this is common for all boards, doesn't it counts as
> dangerous?  This is feature only on our board.

We can probably solve this through a Kconfig option.

But then, if it's working in u-boot right now, I'm not really sure
what it's trying to fix?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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