linux-kernel - Re: [PATCH] mmc: pxamci: Refactor regulator support

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Date:	Thu, 25 Jul 2013 23:03:52 +0200
From:	Andrea Adami <andrea.adami@...il.com>
To:	Mark Brown <broonie@...nel.org>
Cc:	linux-mmc@...r.kernel.org, Chris Ball <cjb@...top.org>,
	Russell King <linux@....linux.org.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Marko Katic <dromede@...il.com>
Subject: Re: [PATCH] mmc: pxamci: Refactor regulator support

On Mon, Jul 22, 2013 at 1:03 PM, Mark Brown <broonie@...nel.org> wrote:
> On Sun, Jul 21, 2013 at 01:07:48AM +0200, Andrea Adami wrote:
>
>> The ADS7846 driver _requires_ the use of a voltage regulator
>> or if not present, CONFIG_REGULATOR_DUMMY should be used for proper operation.
>> This was made mandatory by the following commit:
>
> No, CONFIG_REGULATOR_DUMMY should *never* be used in production.
>
>> The ADS7846 in spitz machines is not connected to
>> any power regulator so it needs CONFIG_REGULATOR_DUMMY enabled.
>
> I don't think that's the case, it would be a very unusual piece of
> silicon that was able to operate without power.  It may be that it's not
> using a software controllable regulator but there will be one or more
> power supplies.  Judging by your problem here it seems like there is
> actually a software controllable regulator though...
>
>> However, enabling CONFIG_REGULATOR and CONFIG_REGULATOR_DUMMY
>> will break pxamci driver and cause the following error output:
>
> This is why you should never use CONFIG_REGULATOR_DUMMY in production,
> it's just a crutch to help things boot during development.
>
>> Regulator support in pxamci_init_ocr() is not
>> written with the existence of the dummy regulator driver in
>> mind. It does not check the return value of mmc_regulator_get_ocrmask()
>> and it will only fall back to platform data if no regulator was found.
>
> No regulator driver should be written with CONFIG_REGULATOR_DUMMY in
> mind.  My guess here is that your custom callbacks for this board should
> be being replaced by a regulator, for example the fixed voltage
> regulator if there's only one voltage supported.


Thanks Mark,

patch is withdrawn.

In fact adding regulators has been self-inflicted pain...
Poodle and spitz boot normally with # CONFIG_REGULATOR is not set.

Sorry for the noise

Andrea Adami
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