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From: Arnd Bergmann <arnd@arndb.de>
To: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org,
	thomas.petazzoni@free-electrons.com, zmxu@marvell.com,
	devicetree@vger.kernel.org, netdev@vger.kernel.org,
	Antoine Tenart <antoine.tenart@free-electrons.com>,
	linux-kernel@vger.kernel.org,
	alexandre.belloni@free-electrons.com, jszhang@marvell.com
Subject: Re: [PATCH v4 3/9] Documentation: bindings: net: add the Marvell PXA168 Ethernet controller
Date: Tue, 23 Sep 2014 19:02:33 +0200	[thread overview]
Message-ID: <5150779.ibmzDh88cj@wuerfel> (raw)
In-Reply-To: <5421A28E.7060600@gmail.com>

On Tuesday 23 September 2014 18:40:46 Sebastian Hesselbarth wrote:
> On 09/23/2014 06:29 PM, Arnd Bergmann wrote:
> > On Tuesday 23 September 2014 17:45:52 Sebastian Hesselbarth wrote:
> >> For reference, this is what we have for MVEBU SoCs with multiple ports
> >> per controller:
> >>
> >> eth: ethernet-ctrl@72000 {
> >>          compatible = "marvell,orion-eth";
> ...
> >>          reg = <0x72000 0x4000>;
> ...
> >>
> >>          ethernet-port@0 {
> >>                  compatible = "marvell,orion-eth-port";
> ...
> >>                  phy-handle = <&ethphy>;
> >>          };
> >> };
> >>
> >> mdio: mdio-bus@72004 {
> >>          compatible = "marvell,orion-mdio";
> ...
> >>          reg = <0x72004 0x84>;
> ..
> >>          ethphy: ethernet-phy {
> >>                  /* set phy address in board file */
> >>          };
> >> };
> 
> > But in this example, you have the same registers and the same
> > clocks in two nodes, which are even used by the same device driver
> > at the moment. It's not a big issue, but my feeling is that Antoine's
> > approach was actually better because it more closely reflects
> > the way that the hardware is built.
> 
> I was not referring to the separate mdio bus node, but putting the
> ethernet-phy node as a child of ethernet-ctrl.

Ah, got it (I think). Yes, that makes sense.

The part I don't understand yet is how one uses multiple ports. pxa168_eth.c
seems to be written with the assumption that only one port is ever used at
a time, while mv643xx_eth.c can actually use multiple ports simultaneously.

Do you think that is that a hardware limitation of pxa168_eth or a feature
that nobody so far has needed from the driver?

If there is only one port and we just have to know which one that is,
I don't think we need the child nodes, but if one can have multiple
ports operate independently then the driver will need a rework 
to actually be usable with that configuration.


	Arnd

  reply	other threads:[~2014-09-23 17:02 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-23 12:15 [PATCH v4 0/9] ARM: Berlin: Ethernet support Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 1/9] net: pxa168_eth: clean up Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 2/9] net: pxa168_eth: add device tree support Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 3/9] Documentation: bindings: net: add the Marvell PXA168 Ethernet controller Antoine Tenart
2014-09-23 12:38   ` Arnd Bergmann
2014-09-23 14:01     ` Antoine Tenart
2014-09-23 14:29       ` Antoine Tenart
2014-09-23 14:37         ` Arnd Bergmann
2014-09-23 15:45           ` Sebastian Hesselbarth
     [not found]             ` <542195B0.6080706-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-09-23 16:29               ` Arnd Bergmann
2014-09-23 16:40                 ` Sebastian Hesselbarth
2014-09-23 17:02                   ` Arnd Bergmann [this message]
2014-09-23 17:31                     ` Sebastian Hesselbarth
     [not found]                       ` <5421AE7C.30504-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2014-09-23 18:18                         ` Arnd Bergmann
2014-09-23 14:33       ` Arnd Bergmann
2014-09-23 14:41         ` Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 4/9] net: pxa168_eth: fix Ethernet flow control status Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 5/9] net: pxa168_eth: set the mac address on the Ethernet controller Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 6/9] net: pxa168_eth: rework the MAC address setup Antoine Tenart
     [not found] ` <1411474536-22626-1-git-send-email-antoine.tenart-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2014-09-23 12:15   ` [PATCH v4 7/9] net: pxa168_eth: allow Berlin SoCs to use the pxa168_eth driver Antoine Tenart
2014-09-23 12:40     ` Arnd Bergmann
2014-09-23 13:50       ` Antoine Tenart
2014-09-23 12:15   ` [PATCH v4 8/9] ARM: dts: berlin: add the Ethernet node Antoine Tenart
2014-09-23 12:15 ` [PATCH v4 9/9] ARM: dts: berlin: enable the Ethernet port on the BG2Q DMP Antoine Tenart
2014-09-23 12:41 ` [PATCH v4 0/9] ARM: Berlin: Ethernet support Arnd Bergmann
2014-09-23 14:01   ` Antoine Tenart

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