netdev - Re: mt7530: dsa_switch_parse_of() fails, causes probe code to run twice

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Message-ID: <e10aa146-c307-8a14-3842-ae50ceabf8cc@arinc9.com>
Date:   Sat, 15 Apr 2023 02:23:16 +0300
From:   Arınç ÜNAL <arinc.unal@...nc9.com>
To:     Daniel Golle <daniel@...rotopia.org>
Cc:     Vladimir Oltean <olteanv@...il.com>,
        Frank Wunderlich <frank-w@...lic-files.de>,
        netdev <netdev@...r.kernel.org>, erkin.bozoglu@...ont.com
Subject: Re: mt7530: dsa_switch_parse_of() fails, causes probe code to run
 twice

On 15.04.2023 01:48, Daniel Golle wrote:
> On Sat, Apr 15, 2023 at 01:41:07AM +0300, Arınç ÜNAL wrote:
>> Hey there,
>>
>> I've been working on the MT7530 DSA subdriver. While doing some tests, I
>> realised mt7530_probe() runs twice. I moved enabling the regulators from
>> mt7530_setup() to mt7530_probe(). Enabling the regulators there ends up
>> with exception warnings on the first time. It works fine when
>> mt7530_probe() is run again.
>>
>> This should not be an expected behaviour, right? Any ideas how we can make
>> it work the first time?
> 
> Can you share the patch or work-in-progress tree which will allow me
> to reproduce this problem?

I tested this on vanilla 6.3-rc6. There's just the diff below that is 
applied. I encountered it on the standalone MT7530 on my Bananapi 
BPI-R2. I haven't tried it on MCM MT7530 on MT7621 SoC yet.

> 
> It can of course be that regulator driver has not yet been loaded on
> the first run and -EPROBE_DEFER is returned in that case. Knowing the
> value of 'err' variable below would hence be valuable information.

Regardless of enabling the regulator on either mt7530_probe() or 
mt7530_setup(), dsa_switch_parse_of() always fails.

Arınç