linux-kernel - Re: [PATCH 2/4] wl1251: move power GPIO handling into the driver

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Message-ID: <20131028232624.GA950@earth.universe>
Date:	Tue, 29 Oct 2013 00:26:26 +0100
From:	Sebastian Reichel <sre@...g0.de>
To:	Mark Brown <broonie@...nel.org>
Cc:	Grazvydas Ignotas <notasas@...il.com>,
	Alexander Shiyan <shc_work@...l.ru>,
	Luciano Coelho <luca@...lho.fi>,
	Mark Rutland <mark.rutland@....com>,
	devicetree@...r.kernel.org, Russell King <linux@....linux.org.uk>,
	Pawel Moll <pawel.moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Tony Lindgren <tony@...mide.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Stephen Warren <swarren@...dotorg.org>,
	linux-doc@...r.kernel.org,
	"John W. Linville" <linville@...driver.com>,
	Rob Herring <rob.herring@...xeda.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Sachin Kamat <sachin.kamat@...aro.org>,
	Bill Pemberton <wfp5p@...ginia.edu>,
	Felipe Balbi <balbi@...com>, Rob Landley <rob@...dley.net>,
	netdev@...r.kernel.org,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/4] wl1251: move power GPIO handling into the driver

Hi,

On Mon, Oct 28, 2013 at 12:23:54PM -0700, Mark Brown wrote:
> On Mon, Oct 28, 2013 at 07:29:52PM +0200, Grazvydas Ignotas wrote:
> 
> > When wl12xx family of chips is connected through SDIO, we already have
> > that pin set up as a regulator controlled with the help of mmc
> > subsystem. When time comes to communicate with the chip, mmc subsystem
> > sees this as yet another SD card and looks for associated regulator
> > for it, and the board file has that set up as a fixed regulator
> > controlling that pin (see pandora_vmmc3 in
> > arch/arm/mach-omap2/board-omap3pandora.c). To prevent poweroff after
> > first SDIO communications are over, pm_runtime calls are used in
> > drivers/net/wireless/ti/wl1251/sdio.c .
> 
> Is this actually controlling VMMC though, or is it some other control?
> If it's not controlling VMMC then it shouldn't say that it is.
> 
> > I don't know if something similar can be done done in SPI case, but
> > I'm sure this is not the first your-so-called regulator misuse.
> 
> It's not the first but that doesn't make controlling something other
> than a regulator through the regulator API any less broken.

I gave it a second try to find out details for this pin:

1. The pin is named PMEN in the Nokia N900 schematics
2. PMEN is described as "Power management enable - system shutdown"
   in a crippled datasheet of the wl1253, which I found in the internet.

I don't think this is supposed to be handled by the regulator API.

-- Sebastian

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