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Date: Thu, 06 Mar 2014 16:47:30 +0100
From: Gregory CLEMENT <gregory.clement@free-electrons.com>
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To: Andrew Lunn <andrew@lunn.ch>
CC: Jason Cooper <jason@lakedaemon.net>,
        Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
        Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
        linux-arm-kernel@lists.infradead.org, Lior Amsalem <alior@marvell.com>,
        Tawfik Bayouk <tawfik@marvell.com>, Nadav Haklai <nadavh@marvell.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: mvebu: add Device Tree for the Armada 385 RD board
References: <1394107868-26094-1-git-send-email-gregory.clement@free-electrons.com> <20140306131429.GJ4780@lunn.ch> <5318779C.8030901@free-electrons.com> <20140306142117.GL4780@lunn.ch> <531886B4.2070002@free-electrons.com> <20140306144600.GM4780@lunn.ch> <53188B73.4000109@free-electrons.com>
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On 06/03/2014 15:51, Gregory CLEMENT wrote:
> On 06/03/2014 15:46, Andrew Lunn wrote:
>>>>>> I think you can use aliases to get the order correct, independent of
>>>>>> how you list them in DT. That should be a lot safer than assuming
>>>>>> things are instantiated from top to bottom.
>>>>>
>>>>> It sounds interesting, how would you do this?
>>>>
>>>> As there already is in armada-370-xp.dtsi
>>>>
>>>>         aliases {
>>>>                 eth0 = &eth0;
>>>>                 eth1 = &eth1;
>>>>         };
>>>>
>>>>
>>>> 	eth0: ethernet@70000 {
>>>> 	}
>>>>         eth1: ethernet@74000 {
>>>> 	}
>>>>
>>>> This at least works for i2c devices. The pdev->id is set using the
>>>> alias number.
>>>
>>> Well I think it doesn't work with ethernet devices because we already do
>>> this in aramda-38x.dtsi:
>>>
>>> 	aliases {
>>> 		gpio0 = &gpio0;
>>> 		gpio1 = &gpio1;
>>> 		eth0 = &eth0;
>>> 		eth1 = &eth1;
>>> 		eth2 = &eth2;
>>> 	};
>>>
>>> 	eth1: ethernet@30000 {
>>> 	}
>>> 	eth2: ethernet@34000 {
>>> 	}
>>> 	eth0: ethernet@70000 {
>>> 	}
>>
>> Ah, Erm, O.K. 
>>
>> It seems to be an i2c thing. Take a look at i2c_add_adapter().
>>
>>         if (dev->of_node) {
>>                 id = of_alias_get_id(dev->of_node, "i2c");
>>  
>> You could put something similar into the ethernet driver.
>>
> 
> 
> Actually even what I did, didn't work as I expected. The order should have been changed in
> the dsi file.
> 
> I will have a look on the ethernet driver.

Well the naming is done in __dev_alloc_name() and it depends on
the probe order.

So I really wonder if we should not put the ethernet@70000 before the othe
Ethernet node in the armada-38x.dts file. Otherwise it is very misleading to
have eth0 for the second interface, eth1 for the third one, and eth2 for
the first one.


Thanks,

Gregory

> 
> 
> Thanks,
> 
> Gregory
> 
> 
>>     Andrew
>>
> 
> 


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com