Re: [PATCH 2/2] ARM: dt: tegra: cardhu: register core regulator tps65911

[Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On 06/02/2012 04:19 PM, Olof Johansson wrote:
> [+devicetree-discuss and grant/rob]
> 
> On Fri, Jun 1, 2012 at 2:04 PM, Mark Brown
> <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org> wrote:
>> On Fri, Jun 01, 2012 at 02:44:00PM -0600, Stephen Warren wrote:
>>
>>> Could you expand on "named property" a bit; I'm not quite sure what
>>> you're getting at - literally a property with name "named" (which
>>> would be the same as regulator-id under just a different property
>>> name), or ...?
>>
>> Just a property where we only care about a name (ie, that the property
>> is present).
>>
>>>> Can't we use the right hand side of this?  It appears to just be
>>>> syntactic sugar without any current meaning.
>>
>>> The stuff to the right of @ is the "unit address" and must match the
>>> value in the reg property. Using that was the first proposal I had
>>> above (which I also didn't like as much)
>>
>> The stuff to the left of the @ is just noise right now, though - it has
>> no meaning currently.  It's filled in with "regulator" because we need
>> to put something there AFAICT.
> 
> Right. In general (and historically) in the device tree, names of the
> nodes should have meaning for the person reading the device tree, but
> it's not meant to be used for software to figure out the hardware
> configuration -- that should instead be handled through compatible +
> other properties.
> 
> Names are generally kept fairly generic (ethernet, cpus, memory, pci, etc).
> 
> Where it starts to become gray area is when it comes down to specific
> bindings, and essentially the device nodes underneath of those
> devices. It's been generally accepted that we can put meaning to the
> names there if needed, but it's still better to avoid it.
> 
> I was originally OK with the regulator binding where names have
> meaning, but after having looked at it a bit recently when looking at
> bindings for some new boards we have, I realized that the original
> suggestion for regulator bindings doesn't necessarily isolate the
> naming dependencies to only be under the regulators in question. In
> particular, for things such as fixed regulators, they can be located
> at other places in the device tree.
> 
> Maybe the solution to that case is to just aggregate them in one place
> and make a pseudo-binding for that (or those, in case of multiple
> locations).
> 
> On the rest of the name-has-meaning discussion, I think it would be
> cleaner to move away from it now while there's relatively few users of
> it (with a migratin path), rather than revise it later. But I'll leave
> it to Grant and Rob to decide which way the prefer things to be. I
> think they might both be travelling around LC/LinuxCon events at the
> moment though.

I tend to agree with Steven's and Olof's comments in this thread. As the
node names generally don't have much meaning, I don't think we should
start now. We've already got multiple styles of bindings and I don't
think we need more.

Rob


> 
> -Olof
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