linux-kernel - Re: [Regulator] Request for clarification - GPIO controlled regulator, USB VBUS,

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Message-ID: <abe393e3-66fe-3c00-8b87-2375cc01d6f5@majess.pl>
Date:   Wed, 4 Oct 2017 13:54:49 +0200
From:   Łukasz Majewski <l.majewski@...ess.pl>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-input@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Subject: Re: [Regulator] Request for clarification - GPIO controlled
 regulator, USB VBUS,

Hi Mark,

> On Wed, Oct 04, 2017 at 12:45:39PM +0200, Łukasz Majewski wrote:
>>> On Tue, Oct 03, 2017 at 06:58:00PM +0200, Łukasz Majewski wrote:
> 
>>>   Perhaps this is something
>>> that could be implemented generically for USB as it's a hotpluggable bus
> 
>> In this case we use VBUS as a power supply voltage. The problem with
>> regulator API used in this case is that we enable it on boot-up, but then we
>> cannot "symulate hotplug" anymore.
> 
> I don't really understand what you mean there, sorry. 

I do use "regulator-fixed" to control VBUS.

The USB driver used regulator_enable/disable to supply power of VBUS.


What I do want to achieve:

For testing purpose I would like to enable/disable this supply (VBUS) 
and force/restart of re-enumeration.

> The majority of
> regulator usage is to supply power, use as reference voltages or
> similar.
> 


-- 
Best regards.

Łukasz Majewski