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Subject: Re: [RESEND PATCH 7/7] regulator: isl9305: Export OF module alias
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To: Mark Brown <broonie@kernel.org>
References: <1440484277-32675-1-git-send-email-javier@osg.samsung.com>
 <1440484277-32675-8-git-send-email-javier@osg.samsung.com>
 <20150825162054.GA12878@sirena.org.uk>
Cc: linux-kernel@vger.kernel.org, Liam Girdwood <lgirdwood@gmail.com>
From: Javier Martinez Canillas <javier@osg.samsung.com>
Message-ID: <55DCA6F0.8070808@osg.samsung.com>
Date: Tue, 25 Aug 2015 19:33:36 +0200
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Hello Mark,

On 08/25/2015 06:20 PM, Mark Brown wrote:
> On Tue, Aug 25, 2015 at 08:31:17AM +0200, Javier Martinez Canillas wrote:
>> The I2C core always reports the MODALIAS uevent as "i2c:<modalias>"
>> regardless of the mechanism that was used to register the device
>> (i.e: OF or board code) and the table that is used later to match
>> the driver with the device (i.e: I2C id table or OF match table).
>>
>> So drivers needs to export the I2C id table and this be built into
>> the module or udev won't have the necessary information to autoload
>> the needed driver module when the device is added.
>>
>> But this means that OF-only drivers needs to have both OF and I2C id
>> tables that have to be kept in sync and also the dev node compatible
>> manufacturer prefix is stripped when reporting the MODALIAS. Which can
>> lead to issues if two vendors use the same I2C device name for example.
>>
>> To avoid the above, the I2C core behavior may be changed in the future
>> to not require an SPI device table for OF-only drivers and report the
>> OF module alias. So, it's better to also export the OF table even when
>> is unused now to prevent breaking module loading when the core changes.
> 
> So, on the one hand detailed commit messages are nice.  On the other
> hand if they wander too far off point it can be hard to sustain
> interest and one can glaze over a bit.  All the above really needs to
> say is that if we want to use the OF alias table we need to export it.
> 

Ok, I wanted to explain why needs to be added even if currently
is not used. But I'll post a v2 with a shorter commit message.

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America
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