linux-kernel - Re: [PATCH v2 02/18] dt-bindings: timer: sp804: add timer-width property

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Date:	Thu, 17 Mar 2016 14:00:48 -0500
From:	Rob Herring <robh@...nel.org>
To:	Robin Murphy <robin.murphy@....com>
Cc:	Neil Armstrong <narmstrong@...libre.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Sudeep Holla <sudeep.holla@....com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	Thomas Gleixner <tglx@...utronix.de>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 02/18] dt-bindings: timer: sp804: add timer-width property

On Thu, Mar 17, 2016 at 1:06 PM, Robin Murphy <robin.murphy@....com> wrote:
> Hi Rob,
>
> On 17/03/16 17:09, Rob Herring wrote:
>>
>> On Wed, Mar 09, 2016 at 11:24:04AM +0100, Neil Armstrong wrote:
>>>
>>> Add timer-width optional property to specify a different vendor
>>> specific timer counter bit-width.
>>>
>>> Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
>>> ---
>>>   Documentation/devicetree/bindings/timer/arm,sp804.txt | 2 ++
>>>   1 file changed, 2 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/timer/arm,sp804.txt
>>> b/Documentation/devicetree/bindings/timer/arm,sp804.txt
>>> index 5cd8eee7..141e143 100644
>>> --- a/Documentation/devicetree/bindings/timer/arm,sp804.txt
>>> +++ b/Documentation/devicetree/bindings/timer/arm,sp804.txt
>>> @@ -17,6 +17,8 @@ Optional properties:
>>>   - arm,sp804-has-irq = <#>: In the case of only 1 timer irq line
>>> connected, this
>>>         specifies if the irq connection is for timer 1 or timer 2. A
>>> value of 1
>>>         or 2 should be used.
>>> +- arm,timer-width: Should contain the width in number of bits of the
>>> counter,
>>> +       is considered by default 32 but can be changed for vendor
>>> variants.
>>
>>
>> That would not be an SP804 nor would the vendor be ARM in that case. So
>> add a new compatible string for the vendor that decided to hack up ARM's
>> IP block.
>
>
> By all accounts this is some ancient reference design[1] which later evolved
> _into_ the SP804, so that vendor would probably still be ARM ;)

Right.

> A separate compatible string would indeed make more sense, though. Both
> semantically and in terms of letting the driver account for the differences
> automatically.
>
> Robin.
>
> [1]:http://infocenter.arm.com/help/topic/com.arm.doc.ddi0170a/I350250.html

Humm, same as integrator timers perhaps?

Rob

>
>>
>> Rob
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>

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