linux-kernel - Re: da9030: ldo11 ignores disable

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Date:	Tue, 14 Jul 2009 23:17:34 +0800
From:	Eric Miao <eric.y.miao@...il.com>
To:	Jonathan Cameron <jic23@....ac.uk>
CC:	Liam Girdwood <lrg@...mlogic.co.uk>,
	LKML <linux-kernel@...r.kernel.org>,
	Mark Brown <broonie@...ena.org.uk>, mike.rapoport@...il.com,
	Paul Shen <bshen9@...vell.com>,
	Haojian Zhuang <hzhuang1@...vell.com>
Subject: Re: da9030: ldo11 ignores disable

Eric Miao wrote:
> Jonathan Cameron wrote:
>> Liam Girdwood wrote:
>>> On Thu, 2009-06-25 at 15:39 +0000, Jonathan Cameron wrote:
>>>> Hi All,
>>>>
>>>> Whilst testing a regulator machine config I've run into a weird issue.
>>>>
>>>> The preliminary data sheet I have suggests that there are two enable
>>>> registers
>>>> for ldo11 but neither rctl22 or rctl11 seems to have any effect (on
>>>> their own
>>>> or both cleared together). I can change the voltage just fine, but not
>>>> actually turn it off.
>>>>
>>>> Anyone come across this problem or have any idea what is going on?
>>> I've come across something similar in the past with two enable bits
>>> causing I2C register cache coherency issues. The cache bits became out
>>> of sync with reality and stopped some I2C writes happening.
>> Don't thing that could happen here.
>>> Another option is that your hardware config doesn't allow ldo11 to be
>>> disabled ?
>> Other than the obvious possibility that the hardware has a bug, I can't
>> seem to find a reason why this shouldn't work.
>>
> 
> I didn't meet this problem, Haojian & Paul, ever had this problem before?
> Or try lookup the Errata for the Arava chip.

Hi Jonathan,

Here's a hint, check register 0x1b - which looks suspicious to me to have
some side effects to LDO11.
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