linux-kernel - Re: [PATCH 4/4] USB: TWL6025 allow different regulator name

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Message-ID: <1304946719.3192.10.camel@odin>
Date:	Mon, 09 May 2011 14:11:59 +0100
From:	Liam Girdwood <lrg@...nel.org>
To:	balbi@...com
Cc:	Graeme Gregory <gg@...mlogic.co.uk>, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org, sameo@...ux.intel.com,
	broonie@...nsource.wolfsonmicro.com
Subject: Re: [PATCH 4/4] USB: TWL6025 allow different regulator name

On Mon, 2011-05-09 at 15:16 +0300, Felipe Balbi wrote:
> Hi,
> 
> On Mon, May 09, 2011 at 12:43:49PM +0100, Liam Girdwood wrote:
> > On Mon, 2011-05-09 at 12:03 +0300, Felipe Balbi wrote:
> > > Hi,
> > > 
> > > On Sun, May 08, 2011 at 04:08:37PM +0100, Liam Girdwood wrote:
> > > > On Wed, 2011-04-27 at 13:45 +0300, Felipe Balbi wrote:
> > > > > Hi,
> > > > > 
> > > > > On Wed, Apr 27, 2011 at 10:39:51AM +0100, Graeme Gregory wrote:
> > > > > > The twl6025 uses a different regulator for USB than the 6030 so select
> > > > > > the correct regulator name depending on the subclass of device.
> > > > > > 
> > > > > > Signed-off-by: Graeme Gregory <gg@...mlogic.co.uk>
> > > > > 
> > > > > I don't see the point of this patch. It's just a string. Use the same
> > > > > name and add a comment saying that on datasheet/TRM/documentation the
> > > > > name LDO is actually referred to as LDOUSB. It's the same functionality
> > > > > anyway.
> > > > > 
> > > > 
> > > > I think for the avoidance of any doubt, it's probably best to use the
> > > > TWL6025 string name here as it will importantly match the TWL6025 TRM
> > > > and any schematics using the TWL6025. Getting this wrong during TWL6025
> > > > board integration has the potential for hardware damage.
> > > 
> > > I would rather have something that doesn't depend on a correct string
> > > and matches based on the device pointer instead. I agree that having the
> > > correct string makes it easier to reference schematics/trm and the like,
> > > but making the SW depend on the correct spelling of a simple string, is
> > > too much for me :-(
> > > 
> > > Specially when getting it wrong "has the potential for hardware damage"
> > > :-)
> > > 
> > 
> > I think it's the lesser evil though, especially for device integrators.
> > They will just match the regulator name from the schematics together
> > with the TRM name when creating their regulator constraints and having
> > different names here will definitely cause confusion.
> 
> Any chance Device Tree could be used to pass that data to kernel
> instead, together with regulator names and all needed data for each one
> of them ?
> 

Yes, I think this should be the long term aim, but atm we will have to
stick with current implementation until regulator has device tree
support.

Liam

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