Hi Lars,
On 11-04-2016 13:23, Lars-Peter Clausen wrote:
On 04/11/2016 01:32 PM, Jose Abreu wrote:
Hi Lars,
On 11-04-2016 10:33, Lars-Peter Clausen wrote:
On 04/11/2016 11:27 AM, Jose Abreu wrote:
Hi Lars,
On 09-04-2016 16:02, Lars-Peter Clausen wrote:
On 04/08/2016 06:12 PM, Jose Abreu wrote: [...]
> [...] >> +- adi,enable-audio: If set the ADV7511 driver will register a codec interface >> + into ALSA SoC. > This is not a description of the hardware. Is this okay: "adi,enable-audio: Set this boolean parameter if ADV7511 transmitter routes audio signals" ?
I don't think we need this property. There is no problem with registering the audio part unconditionally. As long as there is no connection we wont create a sound card that is exposed to userspace.
This change was suggested by Laurent Pinchart and was introduced in v3. Quoting Laurent: "The idea is that enabling support for ADV7511 audio in the kernel isn't coupled with whether the system includes audio support. It would be confusing, and would also waste resources, to create a Linux sound device when no sound channel is routed on the board."
I wouldn't care too much about this at this point, the extra amount of resources required for registering the CODEC (but not the sound card) is just a few bytes (sizeof(struct snd_soc_codec)).
Nevertheless what we should do is describe the hardware and from this information infer whether there is a audio connection or not and if there is none we might skip registering the CODEC. In my opinion this hardware description should be modeled using of-graph, having a connection between the SoC side and the adv7511 SPDIF or I2S port.
You mean something like this:
sound_playback: sound_playback { compatible = "simple-audio-card"; [...] simple-audio-card,format = "i2s"; [...] }
adv7511@xx { compatible = "adi,adv7511"; [...]
ports { [...] /* Audio Output */ port@x { reg = <x>; endpoint { remote-endpoint = <&sound_playback>; } } }}
Yes, something like that. Not exactly like that, but similar. One of the core concepts of of-graph is that there is always a description of the connection from both sides, this way each side can independently figure out where it is connected.
Currently there is also zero support of of-graph in ASoC, so a bit of work is required to get this integrated properly.
I also believe this would be the better option but in the meantime can't I integrate the audio like it is being done in the dw-hdmi driver[1]? In this driver the audio is registered as a sound card and is conditionally built using Kconfig, just like I was doing in the previous versions. I know you said the HDMI audio is still an open issue but it seems that for this case it was accepted.
[1] http://lxr.free-electrons.com/source/drivers/gpu/drm/bridge/dw-hdmi-ahb-audi...
Best regards, Jose Miguel Abreu