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Date:   Mon, 5 Sep 2022 18:41:33 -0700
From:   Tao Ren <rentao.bupt@gmail.com>
To:     Andrew Lunn <andrew@lunn.ch>
Cc:     "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Heyi Guo <guoheyi@linux.alibaba.com>,
        Dylan Hung <dylan_hung@aspeedtech.com>,
        Guangbin Huang <huangguangbin2@huawei.com>,
        Liang He <windhl@126.com>, Hao Chen <chenhao288@hisilicon.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>, Tao Ren <taoren@fb.com>,
        netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 2/2] ARM: dts: aspeed: elbert: Enable mac3
 controller
Message-ID: <YxalTToannPyLQpI@taoren-fedora-PC23YAB4>
References: <20220905235634.20957-1-rentao.bupt@gmail.com>
 <20220905235634.20957-3-rentao.bupt@gmail.com>
 <YxaS2mS5vwW4HuqL@lunn.ch>
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Hi Andrew,

On Tue, Sep 06, 2022 at 02:22:50AM +0200, Andrew Lunn wrote:
> On Mon, Sep 05, 2022 at 04:56:34PM -0700, rentao.bupt@gmail.com wrote:
> > From: Tao Ren <rentao.bupt@gmail.com>
> > 
> > Enable mac3 controller in Elbert dts: Elbert MAC3 is connected to the
> > onboard switch directly (fixed link).
> 
> What is the switch? Could you also add a DT node for it?
> 
> > 
> > Signed-off-by: Tao Ren <rentao.bupt@gmail.com>
> > ---
> >  arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts b/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > index 27b43fe099f1..52cb617783ac 100644
> > --- a/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > +++ b/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > @@ -183,3 +183,14 @@ imux31: i2c@7 {
> >  &i2c11 {
> >  	status = "okay";
> >  };
> > +
> > +&mac3 {
> > +	status = "okay";
> > +	phy-mode = "rgmii";
> 
> 'rgmii' is suspicious, though not necessarily wrong. This value is
> normally passed to the PHY, so the PHY inserts the RGMII delay. You
> however don't have a PHY. So i assume the switch is inserting the
> delay? Again, being able to see the DT properties for the switch would
> be useful.
> 
>    Andrew

Thank you for the quick review!

The BMC mac3 is connected to BCM53134P's IMP_RGMII port, and there is no
PHY between BMC MAC and BCM53134P. BCM53134P loads configurations from
its EEPROM when the chip is powered.

Could you please point me an example showing how to describe the switch in
dts? Anyhow I will need to improve the patch description and comments in
v2.


Thanks,

- Tao