Re: [PATCH] driver/i2c/mux: Add register based mux i2c-mux-reg

From: Alexander Sverdlin
Date: Thu Jun 18 2015 - 05:05:11 EST


On 18/06/15 10:08, ext Paul Bolle wrote:
>>>> You do not see the platform_device, because there are no users yet, put
>>>>> > >> > this MODULE_ALIAS() is perfectly fine, it will allow automatic module loading
>>>>> > >> > in non-DT case.
>>> > > Do you mean that it will allow automatic module loading once the patch
>>> > > that adds a struct platform_device with a "i2c-mux-reg" name lands?
>> >
>> > Any platform code which will register the platform_device will trigger uevent and
>> > udevd will be able to find the module with this macro. This is a legacy alternative
>> > to device-tree approach.
> That means I've correctly figured out the purpose of this
> MODULE_ALIAS("platform:" stuff. Because it might actually be documented
> somewhere but I managed to not stumble on that documentation.
> With that out of the way: am I right in thinking there's currently no
> platform code that triggers that uevent for
> "MODALIAS=platform:i2c-mux-reg"? Because if there's no struct
> platform_device taking care of that I think this MODULE_ALIAS() should
> not be added, not yet.

Maybe (and hopefully) there will never be a legacy user of this driver. But this macro
is perfectly fine, adds no overhead (but modinfo) and make the module "complete" in a
sense that it supports both types of binding. There is a legacy probe function in it,
all the support for legacy binding with platform_data in it and this modalias is simply
the last part of it.

Best regards,
Alexander Sverdlin.
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