2014-10-07 05:49:25

by Guenter Roeck

[permalink] [raw]
Subject: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

Devicetree bindings are supposed to be operating system independent
and should thus not describe how a specific functionality is implemented
in Linux.

Cc: Rob Herring <[email protected]>
Cc: Pawel Moll <[email protected]>
Cc: Mark Rutland <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
---
Documentation/devicetree/bindings/mfd/as3722.txt | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/mfd/as3722.txt b/Documentation/devicetree/bindings/mfd/as3722.txt
index 4f64b2a..0b2a609 100644
--- a/Documentation/devicetree/bindings/mfd/as3722.txt
+++ b/Documentation/devicetree/bindings/mfd/as3722.txt
@@ -122,8 +122,7 @@ Following are properties of regulator subnode.

Power-off:
=========
-AS3722 supports the system power off by turning off all its rail. This
-is provided through pm_power_off.
+AS3722 supports the system power off by turning off all its rails.
The device node should have the following properties to enable this
functionality
ams,system-power-controller: Boolean, to enable the power off functionality
--
1.9.1


2014-10-07 10:59:59

by Mark Rutland

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On Tue, Oct 07, 2014 at 06:28:07AM +0100, Guenter Roeck wrote:
> Devicetree bindings are supposed to be operating system independent
> and should thus not describe how a specific functionality is implemented
> in Linux.
>
> Cc: Rob Herring <[email protected]>
> Cc: Pawel Moll <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Signed-off-by: Guenter Roeck <[email protected]>
> ---
> Documentation/devicetree/bindings/mfd/as3722.txt | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

Thanks for the fix-up!

Acked-by: Mark Rutland <[email protected]>

Mark.

>
> diff --git a/Documentation/devicetree/bindings/mfd/as3722.txt b/Documentation/devicetree/bindings/mfd/as3722.txt
> index 4f64b2a..0b2a609 100644
> --- a/Documentation/devicetree/bindings/mfd/as3722.txt
> +++ b/Documentation/devicetree/bindings/mfd/as3722.txt
> @@ -122,8 +122,7 @@ Following are properties of regulator subnode.
>
> Power-off:
> =========
> -AS3722 supports the system power off by turning off all its rail. This
> -is provided through pm_power_off.
> +AS3722 supports the system power off by turning off all its rails.
> The device node should have the following properties to enable this
> functionality
> ams,system-power-controller: Boolean, to enable the power off functionality
> --
> 1.9.1
>
> --
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>

2014-10-07 16:21:38

by Rob Landley

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On 10/07/14 00:28, Guenter Roeck wrote:
> Devicetree bindings are supposed to be operating system independent
> and should thus not describe how a specific functionality is implemented
> in Linux.

So your argument is that linux/Documentation/devicetree/bindings should
not be specific to Linux. Merely hosted in the Linux kernel source
repository.

Well that's certainly a point of view.

Rob

2014-10-07 16:31:43

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On Tue, Oct 07, 2014 at 11:21:11AM -0500, Rob Landley wrote:
> On 10/07/14 00:28, Guenter Roeck wrote:
> > Devicetree bindings are supposed to be operating system independent
> > and should thus not describe how a specific functionality is implemented
> > in Linux.
>
> So your argument is that linux/Documentation/devicetree/bindings should
> not be specific to Linux. Merely hosted in the Linux kernel source
> repository.
>
> Well that's certainly a point of view.
>
Not specifically my argument, really, and nothing new either. But, yes, I do
think that devicetree bindings descriptions should not include implementation
details, especially since those may change over time (as is the case here).

Thanks,
Guenter

2014-10-07 16:58:54

by Mark Rutland

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On Tue, Oct 07, 2014 at 05:21:11PM +0100, Rob Landley wrote:
> On 10/07/14 00:28, Guenter Roeck wrote:
> > Devicetree bindings are supposed to be operating system independent
> > and should thus not describe how a specific functionality is implemented
> > in Linux.
>
> So your argument is that linux/Documentation/devicetree/bindings should
> not be specific to Linux. Merely hosted in the Linux kernel source
> repository.

Precisely. If nothing else as a general guideline this keeps us honest,
and prevents us from embedding arbitrary implementation details into
bidnings that cause pain later when we want to change things at either
end.

There are already otehr users of these bindings, so we can't really
claim they're strictly Linux-specific anyhow.

> Well that's certainly a point of view.

As far as I am aware, it's the point of view shared by the device tree
maintainers, and it's been that way for a while.

I don't really follow your concern. For one thing were this followed
more strictly this file wouldn't need patching at all to correct for
this Linux-internal rework...

Thanks,
Mark.

2014-10-07 16:59:41

by David Daney

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On 10/07/2014 09:31 AM, Guenter Roeck wrote:
> On Tue, Oct 07, 2014 at 11:21:11AM -0500, Rob Landley wrote:
>> On 10/07/14 00:28, Guenter Roeck wrote:
>>> Devicetree bindings are supposed to be operating system independent
>>> and should thus not describe how a specific functionality is implemented
>>> in Linux.
>>
>> So your argument is that linux/Documentation/devicetree/bindings should
>> not be specific to Linux. Merely hosted in the Linux kernel source
>> repository.
>>
>> Well that's certainly a point of view.
>>
> Not specifically my argument, really, and nothing new either. But, yes, I do
> think that devicetree bindings descriptions should not include implementation
> details, especially since those may change over time (as is the case here).
>

I fully agree.

Many device trees come from outside the kernel (i.e. they are supplied
by the system boot environment). Obviously these device trees cannot be
changed at the whim of kernel developers, *and* it is perfectly
reasonable to think that software other than the Linux kernel will run
on this type of system too.

So yes, it is really true, device trees are not a Linux kernel private
implementation detail, they are really an external ABI that, although
documented in the kernel source tree, cannot be changed in incompatible
ways as time progresses.

David Daney


2014-10-07 17:11:13

by Rob Landley

[permalink] [raw]
Subject: Re: [PATCH 05/44] mfd: as3722: Drop reference to pm_power_off from devicetree bindings

On 10/07/14 11:59, David Daney wrote:
> On 10/07/2014 09:31 AM, Guenter Roeck wrote:
>> On Tue, Oct 07, 2014 at 11:21:11AM -0500, Rob Landley wrote:
>>> On 10/07/14 00:28, Guenter Roeck wrote:
>>>> Devicetree bindings are supposed to be operating system independent
>>>> and should thus not describe how a specific functionality is
>>>> implemented
>>>> in Linux.
>>>
>>> So your argument is that linux/Documentation/devicetree/bindings should
>>> not be specific to Linux. Merely hosted in the Linux kernel source
>>> repository.
>>>
>>> Well that's certainly a point of view.
>>>
>> Not specifically my argument, really, and nothing new either. But,
>> yes, I do
>> think that devicetree bindings descriptions should not include
>> implementation
>> details, especially since those may change over time (as is the case
>> here).
>>
>
> I fully agree.
>
> Many device trees come from outside the kernel (i.e. they are supplied
> by the system boot environment). Obviously these device trees cannot be
> changed at the whim of kernel developers, *and* it is perfectly
> reasonable to think that software other than the Linux kernel will run
> on this type of system too.
>
> So yes, it is really true, device trees are not a Linux kernel private
> implementation detail, they are really an external ABI that, although
> documented in the kernel source tree, cannot be changed in incompatible
> ways as time progresses.

Ah. Existing thing with backstory among the in-crowd, so I'll assume
"git subtree" was previously suggested and you had that discussion
already and decided against it.

Carry on,

Rob