[PATCH v2 02/18] dt-bindings: timer: sp804: add timer-width property
robin.murphy at arm.com
Thu Mar 17 12:21:23 PDT 2016
On 17/03/16 19:00, Rob Herring wrote:
> On Thu, Mar 17, 2016 at 1:06 PM, Robin Murphy <robin.murphy at arm.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 at baylibre.com>
>>>> Documentation/devicetree/bindings/timer/arm,sp804.txt | 2 ++
>>>> 1 file changed, 2 insertions(+)
>>>> diff --git a/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
>>>> + is considered by default 32 but can be changed for vendor
>>> 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 which later evolved
>> _into_ the SP804, so that vendor would probably still be ARM ;)
>> A separate compatible string would indeed make more sense, though. Both
>> semantically and in terms of letting the driver account for the differences
> Humm, same as integrator timers perhaps?
Having had a quick look, what the Integrator/AP manual describes
certainly smells like the same basic block as the "AMBA Timer" - 16 bit
counters and the same control register layout - albeit in a mutant
triple-timer version with a bigger offset between each register set.
Integrator/CP, on the other hand, looks much more SP804-like.
More information about the linux-arm-kernel