linux-kernel - Re: [PATCH] regulator: core: Keep boot

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Message-ID: <4F95495D.4050508@stericsson.com>
Date:	Mon, 23 Apr 2012 14:21:49 +0200
From:	Ulf Hansson <ulf.hansson@...ricsson.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	Liam Girdwood <lrg@...mlogic.co.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Mattias WALLIN <mattias.wallin@...ricsson.com>,
	Jonas ABERG <jonas.aberg@...ricsson.com>,
	Lee Jones <lee.jones@...aro.org>
Subject: Re: [PATCH] regulator: core: Keep boot_on regulators powered during
 init

On 04/23/2012 01:05 PM, Mark Brown wrote:
> On Mon, Apr 23, 2012 at 12:52:05PM +0200, Ulf Hansson wrote:
>
>> I realize that using boot_on, which has been around for quite some
>> time could have problems.  If not using the existing boot_on
>> constraint, do you have an idea of how to accomplish what I want?
>> Should I invent a new constraint option to be used in
>> regulator_init_complete!?
>
> To be honest I don't entirely understand what your goal is at the system
> level - the current idea is that either the regulator will be marked as
> always_on or it should be enabled by a consumer.  What is the scenario
> in which neither of these is sufficient?

The consumer do not want to enable the regulator directly from its 
device probe routine, it is handled through a scheduled work.

Moreover the regulator shall not be switched off unless the consumer 
work decides that this is OK.

So, we actually will have a race were the work _might_ be able to 
preventing the late_init_call (regulator_init_complete) from disabling 
the regulator if has reached the point were it has enabled the regulator.

Hopes this clarifies the background a bit more.


Kind regards
Ulf Hansson

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