linux-kernel - Re: [PATCH] of_mdio: fix phy interrupt passing

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Date:	Mon, 17 Feb 2014 09:48:23 -0800
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Ben Dooks <ben.dooks@...ethink.co.uk>
Cc:	Grant Likely <grant.likely@...aro.org>,
	linux-kernel <linux-kernel@...ts.codethink.co.uk>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	netdev <netdev@...r.kernel.org>,
	Linux-sh list <linux-sh@...r.kernel.org>,
	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Subject: Re: [PATCH] of_mdio: fix phy interrupt passing

2014-02-17 9:42 GMT-08:00 Ben Dooks <ben.dooks@...ethink.co.uk>:
> On 17/02/14 17:26, Florian Fainelli wrote:
>>
>> Hi Ben,
>>
>> 2014-02-17 8:29 GMT-08:00 Ben Dooks <ben.dooks@...ethink.co.uk>:
>>>
>>> The of_mdiobus_register_phy() is not setting phy->irq this causing
>>> some drivers to incorrectly assume that the PHY does not have an
>>> IRQ associated with it or install an interrupt handler for the
>>> PHY.
>>>
>>> Simplify the code setting irq and set the phy->irq at the same
>>> time so that the case if mdio->irq is not NULL is easier to read.
>>
>>
>> The real bug fix, which is not properly explained here, is that
>> irq_of_parse_and_map() should return values > 0 when the interrupt is
>> valid, so this makes me wonder why we are not propagating the return
>> value from irq_of_parse_and_map() in case the call to
>> of_irq_parse_one() does return something non-zero?
>
>
> No, the first issue is phy->dev never gets set, which causes the
> issue. The cleanup was added as it seemed easier to put it in with
> this.

Ok, that really needs to be mentioned in the commit message, even
being quite familiar (and possibly dumb too) with the code, I could
not figure this out by reading your patch.

>
> I think phy->irq is already initialised to PHY_POLL and thus there
> is no need to set phy->irq if the irq_of_parse_and_map() fails.

That is correct, the reason why I introduced 7d97637 ("net: of_mdio:
do not overwrite PHY interrupt configuration") was that you are also
allowed to change the irq type before calling into
of_mdiobus_register(), so we want to preserve other irq values being
set here, such as PHY_IGNORE_INTERRUPT. Your patch does take care of
that since it only overrides the irq in case we could parse it.
-- 
Florian
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