Re: [RFC PATCH 0/3] introduce: Multistate Switch Class

[MyungJoo Ham]

On Fri, Nov 25, 2011 at 11:02 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Thursday 24 November 2011, MyungJoo Ham wrote:
>> For switch ports, which may have different types of cables
>> (USB, TA, HDMI, Analog A/V, and others), we often have seperated device
>> drivers that detect the state changes at the port and device drivers that
>> do something according to the state changes.
>>
>> For example, when MAX8997-MUIC detects a Charger cable insertion, another
>> device driver (such as MAX8903 charger, MAX8997 charger, Charger Manager,
>> or board file) needs to set charger current limit accordingly and when
>> MAX8997-MUIC detects a HDMI cable insertion, multimedia device drivers
>> need to do some operations accordingly.
>>
>> This patchset supports the usage of notifier for passing such information
>> between device drivers.
>>
>> Another issue is that at a single switch port, there might be multiple
>> and heterogeneous cables attached at the same time. Besides, the state
>> (Attached or Detached) of each cable may alter independently.
>>
>> In order to address such issues, Android kernel's "Switch" class seems to
>> be a good basis and we have implemented "Multistate Switch Class" based on
>> it. The "Switch" class code of Android kernel is GPL as well.
>
> How does this relate to the new "pinmux" subsystem that Linus Walleij
> maintains? Would it be useful to integrate your driver into pinmux
> instead of starting a new subsystem?
>
>        Arnd
>

I haven't thought about pinmux subsystem and wasn't aware of it.
However the name, pinmux, suggests that it supports similar devices if
not same. I'll read pinmux subsystem first. Thamks a lot.

Cheers!
MyungJoo



-- 
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab, DMC Business, Samsung Electronics
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