[alsa-devel] [RFC][PATCH 2/2 v3] ASoC: simple-card: add Device Tree support

Stephen Warren swarren at wwwdotorg.org
Mon Feb 4 23:22:21 CET 2013

On 01/31/2013 06:05 PM, Kuninori Morimoto wrote:
> Hi Stephen, Mark
>>> +- simple-audio,dai-name			: simple-audio CPU/CODEC DAI name
>> OK, I see those two are CPU-/CODEC-specific. However, you could easily
>> just have different property names for the two.
>> I assume you didn't like my idea of not putting the DAI names into the
>> DT, but using extra arguments after the phandles instead? Doing so would
>> be more alike most existing DT bindings.
> The reason why I need "dai-name" is that phandle can select "cpu/codec device"
> itself, but, it can't select "port".
> This port is called/controlled as "xxx_dai_name" on ASoC I think.
> like this
> +-------------+
> | FSI  port A |--> ak4642
> |      port B |--> HDMI
> +-------------+
> Then, I would like to ask Stephen, Mark

Yes it can.

In most DT bindings where phandles are used, you specify both a phandle
and some arguments related to that phandle. The arguments could easily
encode the port ID. In other words, instead of:

simple-audio,codec = <&phandle>;

you could write:

simple-audio,codec = <&phandle PORT_NUMBER>;

where PORT_NUMBER could be 0, 1, 2, or any other integer value or
sequence of integer values, which the driver for the CODEC would
interpret itself, and return an ASoC-internal port name.

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