From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
Subject: Re: FW: [PATCH v2] mmc: sdhci: apply voltage range check only for
 non-fixed regulators
Date: Wed, 14 Nov 2012 17:41:07 +0900
Message-ID: <20121114084105.GG7407@opensource.wolfsonmicro.com>
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To: Kevin Liu <keyuan.liu@gmail.com>
Cc: m.szyprowski@samsung.com, Chris Ball <cjb@laptop.org>, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, lrg@ti.com, Philip Rakity <prakity@nvidia.com>
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On Wed, Nov 14, 2012 at 04:36:28PM +0800, Kevin Liu wrote:
> 2012/11/14 Mark Brown <broonie@opensource.wolfsonmicro.com>:

> > Should this be regulator_set_voltage_tol()?  Otherwise it'd be good to
> > explain where the numbers come from.

> In SD physical layer spec 3.01 chapter 6.6.1, the threshold level for
> voltage range is defined as below:
> Vdd(min) = 2.7V while Vdd(max) = 3.6V.
> The card should work within the voltage range.

> If you are afraid the voltage value is too aggressive, maybe we can
> use regulator_set_voltage_tol() to set a smaller range.
> But which range should be reasonable?

The above makes total sense - thanks!  I just wasn't aware that the
range was specified in this fashion in the spec.  Might be worth a
comment in the code if you need to respin.

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