path: root/sound/soc/generic/audio-graph-card2.c

// SPDX-License-Identifier: GPL-2.0
//
// ASoC Audio Graph Card2 support
//
// Copyright (C) 2020 Renesas Electronics Corp.
// Copyright (C) 2020 Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
//
// based on ${LINUX}/sound/soc/generic/audio-graph-card.c
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <sound/graph_card.h>

/************************************
	daifmt
 ************************************
	ports {
		format = "left_j";
		port@0 {
			bitclock-master;
			sample0: endpoint@0 {
				frame-master;
			};
			sample1: endpoint@1 {
				format = "i2s";
			};
		};
		...
	};

 You can set daifmt at ports/port/endpoint.
 It uses *latest* format, and *share* master settings.
 In above case,
	sample0: left_j, bitclock-master, frame-master
	sample1: i2s,    bitclock-master

 If there was no settings, *Codec* will be
 bitclock/frame provider as default.
 see
	graph_parse_daifmt().

 "format" property is no longer needed on DT if both CPU/Codec drivers are
 supporting snd_soc_dai_ops :: .auto_selectable_formats.
 see
	snd_soc_runtime_get_dai_fmt()

	sample driver
		linux/sound/soc/sh/rcar/core.c
		linux/sound/soc/codecs/ak4613.c
		linux/sound/soc/codecs/pcm3168a.c
		linux/sound/soc/soc-utils.c
		linux/sound/soc/generic/test-component.c

 ************************************
	Normal Audio-Graph
 ************************************

 CPU <---> Codec

 sound {
	compatible = "audio-graph-card2";
	links = <&cpu>;
 };

 CPU {
	cpu: port {
		bitclock-master;
		frame-master;
		cpu_ep: endpoint { remote-endpoint = <&codec_ep>; }; };
 };

 Codec {
	port {	codec_ep: endpoint { remote-endpoint = <&cpu_ep>; }; };
 };

 ************************************
	Multi-CPU/Codec
 ************************************

It has link connection part (= X,x) and list part (= A,B,a,b).
"links" is connection part of CPU side (= @).

	+----+		+---+
 CPU1 --|A  X| <-@----> |x a|-- Codec1
 CPU2 --|B   |		|  b|-- Codec2
	+----+		+---+

 sound {
	compatible = "audio-graph-card2";

(@)	links = <&mcpu>;

	multi {
		ports@0 {
(@)		mcpu:	port@0 { mcpu0_ep: endpoint { remote-endpoint = <&mcodec0_ep>;	}; };	// (X) to pair
			port@1 { mcpu1_ep: endpoint { remote-endpoint = <&cpu1_ep>;	}; };	// (A) Multi Element
			port@2 { mcpu2_ep: endpoint { remote-endpoint = <&cpu2_ep>;	}; };	// (B) Multi Element
		};
		ports@1 {
			port@0 { mcodec0_ep: endpoint { remote-endpoint = <&mcpu0_ep>;	}; };	// (x) to pair
			port@1 { mcodec1_ep: endpoint { remote-endpoint = <&codec1_ep>;	}; };	// (a) Multi Element
			port@2 { mcodec2_ep: endpoint { remote-endpoint = <&codec2_ep>;	}; };	// (b) Multi Element
		};
	};
 };

 CPU {
	ports {
		bitclock-master;
		frame-master;
		port@0 { cpu1_ep: endpoint { remote-endpoint = <&mcpu1_ep>; }; };
		port@1 { cpu2_ep: endpoint { remote-endpoint = <&mcpu2_ep>; }; };
	};
 };

 Codec {
	ports {
		port@0 { codec1_ep: endpoint { remote-endpoint = <&mcodec1_ep>; }; };
		port@1 { codec2_ep: endpoint { remote-endpoint = <&mcodec2_ep>; }; };
	};
 };

 ************************************
	DPCM
 ************************************

		DSP
	   ************
 PCM0 <--> * fe0  be0 * <--> DAI0: Codec Headset
 PCM1 <--> * fe1  be1 * <--> DAI1: Codec Speakers
 PCM2 <--> * fe2  be2 * <--> DAI2: MODEM
 PCM3 <--> * f