linux-kernel - RE: [PATCH] leds: lm3530: fix handling of already enabled regulators

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Message-ID: <DD6B9D658496A2488636C8C75B9C0CB601DA3AF6@EXMAIL04.scwf.nsc.com>
Date:	Tue, 24 Apr 2012 03:15:09 -0700
From:	"Kim, Milo" <Milo.Kim@...com>
To:	"axel.lin@...il.com" <axel.lin@...il.com>
CC:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Shreshtha Kumar Sahu <shreshthakumar.sahu@...ricsson.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Girdwood, Liam" <lrg@...com>
Subject: RE: [PATCH] leds: lm3530: fix handling of already enabled regulators

> 
> Let me put it this way: Assume only this driver is using the regulator.
> If the regulator is enabled on boot, which means the reference count
> is init to 1.
> 

Could you explain what 'enabled on boot' means ?
1) The regulator_enable() is called in initial time
or
2) boot_on = 1 in regulator_init_data ?

If you mean 'boot_on = 1' in regulator_init_data, then no use_count increase.

> Then if we set brt_val to 0 in lm3530_brightness_set, which will then
> call
> regulator_disable(). 

It looks buggy code in lm3530_brightness_set().
Even the regulator_disable() is failed, drvdata->enable is set to false.
I think drvdata->enable is changed to false only when the regulator is off successfully.

Thanks & BR
Milo -
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