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Date: Wed, 11 Jan 2012 17:45:41 +0000
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Thomas Abraham <thomas.abraham@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>, linux-kernel@vger.kernel.org,
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Subject: Re: [PATCH] backlight: lcd: add driver for raster-type lcd's with
	gpio controlled panel reset
Message-ID: <20120111174540.GE24213@opensource.wolfsonmicro.com>
References: <1325778146-27056-1-git-send-email-thomas.abraham@linaro.org> <4F05F509.6020405@metafoo.de> <20120106064929.GB3496@opensource.wolfsonmicro.com> <CAJuYYwRxuZAm_JpLw1fN2ypnFc6TocH6veRmCeuqENvZHSz3kg@mail.gmail.com> <20120107172826.GA355@opensource.wolfsonmicro.com> <CAJuYYwSuDzUWgnSJHO0vwjYH7zscC9=j_=JuOUuJy9shHpPUuA@mail.gmail.com>
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On Wed, Jan 11, 2012 at 04:21:57PM +0530, Thomas Abraham wrote:

> In the case of Exynos4 based Origen board, buck7 of max8997 supplies
> power to the lcd panel. buck7 is capable of supplying power at
> different voltage levels but for Origen board, it is required to
> supply only 3.3V. The constraints for buck7 can specify 'apply_uV' and
> this will ensure that buck7 is configured to supply 3.3V.

> But 'apply_uV' seems to be not ideal for regulators that supply power
> to lcd panels. It would be better to power lcd panels only when video
> data has to be displayed.

What makes you say this?  Enabling and disabling a regulator are
entirely orthogonal to setting the regulator voltage.