Re: [PATCH 0/3] Implement role-switch notifications from dwc3-drd to dwc3-qcom

[Bryan O'Donoghue <bryan.odonoghue@linaro.org>]

On 25/08/2021 01:01, Bjorn Andersson wrote:
> On Tue 24 Aug 16:58 PDT 2021, Bryan O'Donoghue wrote:
> 
>> On 25/08/2021 00:52, Bjorn Andersson wrote:
>>> But isn't this role switching interaction (both B and C) already part of
>>> the core/drd, so if we can just get the drd to invoke
>>> dwc3_qcom_vbus_overrride_enable() we're done (and can remove all the
>>> extcon code from the qcom glue as well)?
>>
>> Provided we have an acceptable way of triggering when a role-switch happens
>> - then USB role switching itself is a NOP here, its really just a
>> convenience to invoke the callback.
>>
> 
> Thanks for confirming. Then let's come up with an acceptable way, rather
> than duplicating yet another feature already implemented in the core.
> 
> Regards,
> Bjorn
> 

The only other thing to say about USB role-switching is it appears to be 
very much 1:1.

Extcon allows a virtually unlimited number of consumers of an even.

Is it envisaged that a role-switch could or should be consumed by say 3 
or even 4 separate pieces of logic and if not, why not ?

What if we had a magic black box that needed to sit ontop of the QCOM 
layer and further consume a role switch ?

notifier/platform pointer + callback ?

---
bod