[alsa-devel] [PATCH 13/18] ARM: ux500: Add ux500 PCM to DB8500 Device Tree

Lee Jones lee.jones at linaro.org
Mon Jul 30 16:26:58 CEST 2012

On 30/07/12 14:40, Mark Brown wrote:
> On Mon, Jul 30, 2012 at 08:32:43AM +0100, Lee Jones wrote:
>> On 29/07/12 21:50, Mark Brown wrote:
>>> On Fri, Jul 27, 2012 at 01:45:57PM +0100, Lee Jones wrote:
>>>> +		pcm: ux500-pcm {
>>>> +			compatible = "stericsson,ux500-pcm";
>>>> +		};
>>>> +
>>> One of two things is wrong here.  Either you've not provided any
>>> information about the hardware so the driver won't be able to work out
>>> what to talk to or you've not provided any data so you're registering a
>>> purely virtual Linux-internal device via the device tree.
>>> Once more, the idea here is to describe the hardware not to dump Linux's
>>> internal data structures into the device tree.
>> We use it register the driver for probe()ing. In the same way we do
>> for the PMU and Regulators. All three of which actually belong to a
>> different hardware block. Do you know of a better way to register
>> those devices?
> You've not identified which of the two cases above we're in...  assuming
> it's a virtal device look at how the DT bindings for the other platforms
> are doing things.

I thought it would have been obvious by my response. The PMU seems to be 
a virtual device with no registers or IRQs.

I've found a DT which seems to do it in the same way as I do 
'arch/powerpc/boot/dts/p1022ds.dts', but some others call PCM 
registration from the CPU-side DAI probe(). Would that be your preference?

Lee Jones
Linaro ST-Ericsson Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

More information about the Alsa-devel mailing list