[PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@nxp.com>

Some SoCs (like i.MX53) need to specify the SRAM clock in the
device tree via the clocks property.

Add an entry to the optional property section.

Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
Changes since v1:
- Add space before : and use the more common "list of phandle
and clock specifier pairs" term - Vladimir

 Documentation/devicetree/bindings/sram/sram.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
index 267da44..ae6ca34 100644
--- a/Documentation/devicetree/bindings/sram/sram.txt
+++ b/Documentation/devicetree/bindings/sram/sram.txt
@@ -50,6 +50,8 @@ Optional properties in the area nodes:
 		 manipulation of the page attributes.
 - label : the name for the reserved partition, if omitted, the label
           is taken from the node name excluding the unit address.
+- clocks : a list of phandle and clock specifier pairs that controls the
+	   SRAM clock.
 
 Example:
 
-- 
2.7.4

Re: [PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[Rob Herring]

On Tue, Jun 26, 2018 at 08:07:33PM -0300, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> Some SoCs (like i.MX53) need to specify the SRAM clock in the
> device tree via the clocks property.
> 
> Add an entry to the optional property section.
> 
> Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> ---
> Changes since v1:
> - Add space before : and use the more common "list of phandle
> and clock specifier pairs" term - Vladimir
> 
>  Documentation/devicetree/bindings/sram/sram.txt | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
> index 267da44..ae6ca34 100644
> --- a/Documentation/devicetree/bindings/sram/sram.txt
> +++ b/Documentation/devicetree/bindings/sram/sram.txt
> @@ -50,6 +50,8 @@ Optional properties in the area nodes:
>  		 manipulation of the page attributes.
>  - label : the name for the reserved partition, if omitted, the label
>            is taken from the node name excluding the unit address.
> +- clocks : a list of phandle and clock specifier pairs that controls the
> +	   SRAM clock.

A list controlling THE (single) SRAM clock?

Once we start needing clocks, power, or other setup, we really should 
have specific compatible strings (and binding docs) for the SRAM. I'll 
take a single clock though.

Rob

Re: [PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[Fabio Estevam]

On Tue, Jul 3, 2018 at 7:21 PM, Rob Herring <robh@kernel.org> wrote:

>> diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
>> index 267da44..ae6ca34 100644
>> --- a/Documentation/devicetree/bindings/sram/sram.txt
>> +++ b/Documentation/devicetree/bindings/sram/sram.txt
>> @@ -50,6 +50,8 @@ Optional properties in the area nodes:
>>                manipulation of the page attributes.
>>  - label : the name for the reserved partition, if omitted, the label
>>            is taken from the node name excluding the unit address.
>> +- clocks : a list of phandle and clock specifier pairs that controls the
>> +        SRAM clock.
>
> A list controlling THE (single) SRAM clock?

Yes, it is a single SRAM clock.

Will reword it.

Re: [PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[Vladimir Zapolskiy]

Hi Rob, Fabio,

On 07/04/2018 01:21 AM, Rob Herring wrote:
> On Tue, Jun 26, 2018 at 08:07:33PM -0300, Fabio Estevam wrote:
>> From: Fabio Estevam <fabio.estevam@nxp.com>
>>
>> Some SoCs (like i.MX53) need to specify the SRAM clock in the
>> device tree via the clocks property.
>>
>> Add an entry to the optional property section.
>>
>> Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
>> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
>> ---
>> Changes since v1:
>> - Add space before : and use the more common "list of phandle
>> and clock specifier pairs" term - Vladimir
>>
>>  Documentation/devicetree/bindings/sram/sram.txt | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
>> index 267da44..ae6ca34 100644
>> --- a/Documentation/devicetree/bindings/sram/sram.txt
>> +++ b/Documentation/devicetree/bindings/sram/sram.txt
>> @@ -50,6 +50,8 @@ Optional properties in the area nodes:
>>  		 manipulation of the page attributes.
>>  - label : the name for the reserved partition, if omitted, the label
>>            is taken from the node name excluding the unit address.
>> +- clocks : a list of phandle and clock specifier pairs that controls the
>> +	   SRAM clock.
> 
> A list controlling THE (single) SRAM clock?
> 
> Once we start needing clocks, power, or other setup, we really should 
> have specific compatible strings (and binding docs) for the SRAM. I'll 
> take a single clock though.
> 

There are SRAM devices, which take multiple power or clock supplies [1],
where one clock or power domain control enables a segment on SRAM, however
a number of (enabled) segments form a single continuous IO memory space,
hence it could make sense to pluralize clocks in the generic document,
particular device specifics can be described separately.

[1] For reference IRAM on NXP LPC32xx has multiple power controls.

--
Best wishes,
Vladimir

Re: [PATCH v2] dt-bindings: sram: Add 'clocks' as an optional property

[Rob Herring]

On Wed, Jul 4, 2018 at 12:40 AM Vladimir Zapolskiy
<vladimir_zapolskiy@mentor.com> wrote:
>
> Hi Rob, Fabio,
>
> On 07/04/2018 01:21 AM, Rob Herring wrote:
> > On Tue, Jun 26, 2018 at 08:07:33PM -0300, Fabio Estevam wrote:
> >> From: Fabio Estevam <fabio.estevam@nxp.com>
> >>
> >> Some SoCs (like i.MX53) need to specify the SRAM clock in the
> >> device tree via the clocks property.
> >>
> >> Add an entry to the optional property section.
> >>
> >> Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
> >> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> >> ---
> >> Changes since v1:
> >> - Add space before : and use the more common "list of phandle
> >> and clock specifier pairs" term - Vladimir
> >>
> >>  Documentation/devicetree/bindings/sram/sram.txt | 2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/sram/sram.txt b/Documentation/devicetree/bindings/sram/sram.txt
> >> index 267da44..ae6ca34 100644
> >> --- a/Documentation/devicetree/bindings/sram/sram.txt
> >> +++ b/Documentation/devicetree/bindings/sram/sram.txt
> >> @@ -50,6 +50,8 @@ Optional properties in the area nodes:
> >>               manipulation of the page attributes.
> >>  - label : the name for the reserved partition, if omitted, the label
> >>            is taken from the node name excluding the unit address.
> >> +- clocks : a list of phandle and clock specifier pairs that controls the
> >> +       SRAM clock.
> >
> > A list controlling THE (single) SRAM clock?
> >
> > Once we start needing clocks, power, or other setup, we really should
> > have specific compatible strings (and binding docs) for the SRAM. I'll
> > take a single clock though.
> >
>
> There are SRAM devices, which take multiple power or clock supplies [1],
> where one clock or power domain control enables a segment on SRAM, however
> a number of (enabled) segments form a single continuous IO memory space,
> hence it could make sense to pluralize clocks in the generic document,
> particular device specifics can be described separately.

The device specific part still has to say how many clocks and what
they are, so having multiple clocks in the generic binding doesn't buy
you anything. And I don't care to give the impression that we support
multiple clocks with the generic binding.

Rob