Re: More Generic Audio Graph Sound Card idea

25 Aug 2020


      Hi Sameer
...
If we plan to go this way, I think we need to consider board specific
configuration at init time and one at runtime. In that case there
could be multiple compatibles that would get added to the driver and
various other requirements can be managed with behavioral flags
instead from DT?
This is still just idea though...
But for example, if you want to
    1) basically, DT is almost audio-graph
    2) but want to have customized operation for some part
And if "audio-graph-card2" driver has graph_init() exported function,
you can create your own drviver, and use customized audio-graph
by using .hooks.
This is just idea/sample, but I'm not sure this is enough or not,
and/or if I can do what I want.
But do you think it can solve your issue ?
-- own driver ---
    static const struct of_device_id graph_of_match[] = {
=>		{ .compatible = "sameer-audio-graph" },
    	{},
    };
static audio_graph_hooks hooks = {
    	.parse_of_hook_pre  = xxx,
=>		.parse_of_hook_post = sameer_parse_of_post,
    	.dai_link_of_pre    = xxx,
    	.dai_link_of_post   = xxx,
=>		.init               = sameer_init,
    	...
    };
=>	int sameer_init(struct snd_soc_pcm_runtime *rtd)
    {
    	/*
    	 * This will be called runtime init timing.
    	 * Call original asoc_simple_dai_init() first
    	 * and do own init, for example.
    	 */
    	asoc_simple_dai_init(rtd);
do_something_own_settings(rtd->xxx);
    }
=>	static int sameer_parse_of_post(struct asoc_simple_priv *priv)
    {
    	struct sameer_priv *my_priv = graph_priv_to_my_priv(priv);
/*
    	 * This will be called after audio_graph's graph_parse_of()
    	 */
/*
    	 * Customize own settings here.
    	 *
    	 * Special connection ?
    	 * Special Setings ?
    	 * Calculate something ?
    	 * Overwrite something ?
    	 */
    }
static int sameer_probe(...)
    {
    	struct sameer_priv *my_priv;
    	struct asoc_simple_priv *graph_priv;
my_priv = zalloc();
    	graph_priv = my_priv_to_graph_priv(my_priv);
=>		graph_priv->hooks = hooks
/*
    	 * Basically, it will do same as audio_graph,
    	 * but .hooks will be called if you specified
    	 */
=>		return graph_init(graph_priv);
    }
--- Kconfig ----
config SND_SAMEER_AUDIO_GRAPH_CARD
    	tristate "Sameer's Audio Graph sound card support"
=>		depends on SND_AUDIO_GRAPH_CARD
    	...
---- my-dt ----------
/*
       * DT setting is almost same as audio_graph
       * which is supporting normal and DPCM.
       * You can add own property which will be handled under .hook
       */
                          *************
      PCM0 <------------> *           * <----DAI0----->
                          *  DSP      *
                          *           * <----DAI1----->
                          *************
      PCM1 <------------------------------------------> DAI2
sound {
    		compatible = "sameer-audio-graph";
dais = <&PCM0,	/* for DPCM */
    			&PCM1>  /* for normal*/
    	};
front-end {
    		ports {
    			PCM0: port@0 { pcm0: endpoint { remote-endpoint = <&dsp_f0>; }; };
    			PCM1: port@1 { pcm1: endpoint { remote-endpoint = <&dai2>; }; };
    		};
    	};
dsp {
    		compatible = "audio-graph-card2-dsp";
ports {
    			/* Front End side */
    			port@0 { dsp_f0: endpoint { remote-endpoint = <&pcm0>; }; };
/* Back End side */
    			port@4 { dsp_b0: endpoint { remote-endpoint = <&dai0>; }; };
    			port@5 { dsp_b1: endpoint { remote-endpoint = <&dai1>; }; };
    		};
    	};
back-end {
    		ports {
    			port@0 { dai0: endpoint { remote-endpoint = <&dsp_b0>; }; };
    			port@1 { dai1: endpoint { remote-endpoint = <&dsp_b1>; }; };
    		};
    	};
codec {
    		port { dai2: endpoint { remote-endpoint = <&pcm1>; }; };
    	};
Thank you for your help !!
Best regards
---
Kuninori Morimoto