Subject: [PATCH 04/15] ARM: smp_twd: add device tree support

From: [email-masked] (Marc Zyngier)
Date: Thu, 12 Jan 2012 14:36:26 +0000

Hi Rob,

On 11/01/12 21:05, Rob Herring wrote:
> On 01/11/2012 07:08 AM, Marc Zyngier wrote:
>> Add bindings to support DT discovery of the ARM Timer Watchdog
>> (aka TWD). Only the timer side is converted by this patch.
>>
>> Cc: Rob Herring <[email-masked]>
>> Signed-off-by: Marc Zyngier <[email-masked]>
>> ---
>>  Documentation/devicetree/bindings/arm/twd.txt |   29 +++++++++++
>>  arch/arm/include/asm/smp_twd.h                |    1 +
>>  arch/arm/kernel/smp_twd.c                     |   68 ++++++++++++++++++++-----
>>  3 files changed, 85 insertions(+), 13 deletions(-)
>>  create mode 100644 Documentation/devicetree/bindings/arm/twd.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/twd.txt b/Documentation/devicetree/bindings/arm/twd.txt
>> new file mode 100644
>> index 0000000..a9d5587
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/twd.txt
>> @@ -0,0 +1,29 @@
>> +* ARM Timer Watchdog
>> +
>> +ARM 11MP, Cortex-A5 and Cortex-A9 are often associated with a per-core
>> +Timer-Watchdog (aka TWD), which provides both a per-cpu local timer
>> +and watchdog.
>> +
>> +The TWD is usually attached to a GIC to deliver its two per-processor
>> +interrupts.
>> +
>> +Main node required properties:
>> +
>> +- compatible : Should be one of:
>> +	"arm,cortex-a9-twd"
>> +	"arm,cortex-a5-twd"
>> +	"arm,arm11mp-twd"
>> +	"arm,smp-twd"
>> +
>> +- interrupts : Two interrupts to each core, the first one for the
>> +  timer, the second one for the watchdog.
>> +
>> +- reg : Specify the base address and the size of the TWD.
>> +
>> +Example:
>> +
>> +	twd at 2c000600 {
>> +		compatible = "arm,arm11mp-twd", "arm,smp-twd";
>> +		reg = <0x2c000600 0x100>;
>> +		interrupts = <1 13 0xf01 1 14 0xf01>;
>> +	};
> 
> Why not split the watchdog and timer into 2 nodes? It may not matter
> since there is no driver for the timer. If there was, we would have a
> problem as you can't match 2 drivers to 1 node.

Don't we hit the opposite problem - two nodes with the same address?

	M.
-- 
Jazz is not dead. It just smells funny...