ASoC: fsl-asoc-card: add S/PDIF controller support

Merge series from Elinor Montmasson <elinor.montmasson@savoirfairelinux.com>:

This is a series of patches aiming to make the machine driver
`fsl-asoc-card` compatible with S/PDIF controllers on imx boards.  The
main goal is to allow the use of S/PDIF controllers with ASRC modules.

The `imx-spdif` machine driver already has specific support for S/PDIF
controllers but doesn't support using an ASRC with it. However, the
`fsl-asoc-card` machine driver has the necessary code to create a sound
card which can use an ASRC module.
It is then possible to extend the support for S/PDIF audio cards by
merging the `imx-spdif` driver into `fsl-asoc-card`.

The first three patches adapt the `fsl-asoc-card` driver to support
multiple codec use cases.
The driver can get 2 codec phandles from the device tree, and
codec-related variables are doubled.
`for_each_codecs` macros are also used when possible to ease adding
other multi-codec use cases in the future.
It makes possible to use the two S/PDIF dummy codec drivers
`spdif_receiver` and `spdif_transmitter` instead of `snd-soc-dummy`,
which was used in `imx-spdif`.

The fourth patch merges the S/PDIF support from `imx-spdif` to
`fsl-asoc-card`.
`fsl-asoc-card` offers the same functionalities as `imx-spdif` did, but
this merge also extends the S/PDIF support with the possibility of using
an ASRC.
Compatible "fsl,imx-audio-spdif" is kept, but `fsl-asoc-card` uses
different DT properties compared to `imx-spdif`:
* The "spdif-controller" property from `imx-spdif` is named "audio-cpu"
  in `fsl-asoc-card`.
* `fsl-asoc-card` uses codecs explicitly declared in DT with
  "audio-codec". With an S/PDIF, codec drivers `spdif_transmitter` and
  `spdif_receiver` should be used. Driver `imx-spdif` used instead the
  dummy codec and a pair of boolean properties, "spdif-in" and
  "spdif-out".
Backward compatibility is therefore implemented in `fsl-asoc-card`.
However, it is recommended to use the new properties when needed.
Especially, declaring and using S/PDIF transmitter and/or receiver nodes
is better than using the dummy codec.

The last three patches update the device tree bindings of
`fsl-asoc-card` and update all in-tree device trees to use the
`fsl-asoc-card` properties.
Note that as the old properties are still supported:
* previous versions of in-tree device trees are still supported.
* out-of-tree device trees are still supported.

This series of patches was successfully built for arm64 and x86 on top
of the latest "for-next" branch of the ASoC git tree on the 26th of June
2024.
These modifications have also been tested on an i.MX8MN evaluation board
with a linux kernel RT v6.1.26-rt8.

Documentation/devicetree/bindings/sound/fsl,imx-audio-spdif.yaml

-# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
-%YAML 1.2
----
-$id: http://devicetree.org/schemas/sound/fsl,imx-audio-spdif.yaml#
-$schema: http://devicetree.org/meta-schemas/core.yaml#
-
-title: Freescale i.MX audio complex with S/PDIF transceiver
-
-maintainers:
-  - Shengjiu Wang <shengjiu.wang@nxp.com>
-
-properties:
-  compatible:
-    oneOf:
-      - items:
-          - enum:
-              - fsl,imx-sabreauto-spdif
-              - fsl,imx6sx-sdb-spdif
-          - const: fsl,imx-audio-spdif
-      - enum:
-          - fsl,imx-audio-spdif
-
-  model:
-    $ref: /schemas/types.yaml#/definitions/string
-    description: User specified audio sound card name
-
-  spdif-controller:
-    $ref: /schemas/types.yaml#/definitions/phandle
-    description: The phandle of the i.MX S/PDIF controller
-
-  spdif-out:
-    type: boolean
-    description:
-      If present, the transmitting function of S/PDIF will be enabled,
-      indicating there's a physical S/PDIF out connector or jack on the
-      board or it's connecting to some other IP block, such as an HDMI
-      encoder or display-controller.
-
-  spdif-in:
-    type: boolean
-    description:
-      If present, the receiving function of S/PDIF will be enabled,
-      indicating there is a physical S/PDIF in connector/jack on the board.
-
-required:
-  - compatible
-  - model
-  - spdif-controller
-
-anyOf:
-  - required:
-      - spdif-in
-  - required:
-      - spdif-out
-
-additionalProperties: false
-
-examples:
-  - |
-    sound-spdif {
-        compatible = "fsl,imx-audio-spdif";
-        model = "imx-spdif";
-        spdif-controller = <&spdif>;
-        spdif-out;
-        spdif-in;
-    };

Documentation/devicetree/bindings/sound/fsl-asoc-card.yaml

@@ -65,6 +65,11 @@ properties:
               - fsl,imx-audio-sgtl5000
               - fsl,imx-audio-wm8960
               - fsl,imx-audio-wm8962
+      - items:
+          - enum:
+              - fsl,imx-sabreauto-spdif
+              - fsl,imx6sx-sdb-spdif
+          - const: fsl,imx-audio-spdif
       - items:
           - enum:
               - fsl,imx-audio-ac97
@@ -81,6 +86,7 @@ properties:
               - fsl,imx-audio-wm8960
               - fsl,imx-audio-wm8962
               - fsl,imx-audio-wm8958
+              - fsl,imx-audio-spdif
 
   model:
     $ref: /schemas/types.yaml#/definitions/string
@@ -93,8 +99,15 @@ properties:
       need to add ASRC support via DPCM.
 
   audio-codec:
-    $ref: /schemas/types.yaml#/definitions/phandle
-    description: The phandle of an audio codec
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description: |
+      The phandle of an audio codec.
+      With "fsl,imx-audio-spdif", either SPDIF audio codec spdif_transmitter,
+      spdif_receiver or both.
+    minItems: 1
+    maxItems: 2
+    items:
+      maxItems: 1
 
   audio-cpu:
     $ref: /schemas/types.yaml#/definitions/phandle
@@ -150,8 +163,10 @@ properties:
     description: dai-link uses bit clock inversion.
 
   mclk-id:
-    $ref: /schemas/types.yaml#/definitions/uint32
-    description: main clock id, specific for each card configuration.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    description: Main clock id for each codec, specific for each card configuration.
+    minItems: 1
+    maxItems: 2
 
   mux-int-port:
     $ref: /schemas/types.yaml#/definitions/uint32
@@ -167,6 +182,27 @@ properties:
     $ref: /schemas/types.yaml#/definitions/phandle
     description: The phandle of an CPU DAI controller
 
+  spdif-controller:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    deprecated: true
+    description: The phandle of an S/PDIF CPU DAI controller.
+
+  spdif-out:
+    type: boolean
+    deprecated: true
+    description: |
+      If present, the transmitting function of S/PDIF will be enabled,
+      indicating there's a physical S/PDIF out connector or jack on the
+      board or it's connecting to some other IP block, such as an HDMI
+      encoder or display-controller.
+
+  spdif-in:
+    type: boolean
+    deprecated: true
+    description: |
+      If present, the receiving function of S/PDIF will be enabled,
+      indicating there is a physical S/PDIF in connector/jack on the board.
+
 required:
   - compatible
   - model
@@ -195,3 +231,12 @@ examples:
              "AIN2L", "Line In Jack",
              "AIN2R", "Line In Jack";
     };
+
+  - |
+    sound-spdif-asrc {
+        compatible = "fsl,imx-audio-spdif";
+        model = "spdif-asrc-audio";
+        audio-cpu = <&spdif>;
+        audio-asrc = <&easrc>;
+        audio-codec = <&spdifdit>, <&spdifdir>;
+    };

arch/arm/configs/imx_v6_v7_defconfig

@@ -311,7 +311,6 @@ CONFIG_SND_IMX_SOC=y
 CONFIG_SND_SOC_EUKREA_TLV320=y
 CONFIG_SND_SOC_IMX_ES8328=y
 CONFIG_SND_SOC_IMX_SGTL5000=y
-CONFIG_SND_SOC_IMX_SPDIF=y
 CONFIG_SND_SOC_FSL_ASOC_CARD=y
 CONFIG_SND_SOC_AC97_CODEC=y
 CONFIG_SND_SOC_CS42XX8_I2C=y

arch/arm64/configs/defconfig

@@ -940,7 +940,6 @@ CONFIG_SND_SOC_FSL_MICFIL=m
 CONFIG_SND_SOC_FSL_EASRC=m
 CONFIG_SND_IMX_SOC=m
 CONFIG_SND_SOC_IMX_SGTL5000=m
-CONFIG_SND_SOC_IMX_SPDIF=m
 CONFIG_SND_SOC_FSL_ASOC_CARD=m
 CONFIG_SND_SOC_IMX_AUDMIX=m
 CONFIG_SND_SOC_MT8183=m

sound/soc/fsl/Kconfig

@@ -303,15 +303,6 @@ config SND_SOC_IMX_SGTL5000
 	  SND_SOC_FSL_ASOC_CARD and SND_SOC_SGTL5000 to use the newer
 	  driver.
 
-config SND_SOC_IMX_SPDIF
-	tristate "SoC Audio support for i.MX boards with S/PDIF"
-	select SND_SOC_IMX_PCM_DMA
-	select SND_SOC_FSL_SPDIF
-	help
-	  SoC Audio support for i.MX boards with S/PDIF
-	  Say Y if you want to add support for SoC audio on an i.MX board with
-	  a S/DPDIF.
-
 config SND_SOC_FSL_ASOC_CARD
 	tristate "Generic ASoC Sound Card with ASRC support"
 	depends on OF && I2C
@@ -323,6 +314,7 @@ config SND_SOC_FSL_ASOC_CARD
 	select SND_SOC_FSL_ESAI
 	select SND_SOC_FSL_SAI
 	select SND_SOC_FSL_SSI
+	select SND_SOC_FSL_SPDIF
 	select SND_SOC_TLV320AIC31XX
 	select SND_SOC_WM8994
 	select MFD_WM8994

sound/soc/fsl/Makefile

@@ -67,7 +67,6 @@ obj-$(CONFIG_SND_SOC_IMX_PCM_RPMSG) += imx-pcm-rpmsg.o
 snd-soc-eukrea-tlv320-y := eukrea-tlv320.o
 snd-soc-imx-es8328-y := imx-es8328.o
 snd-soc-imx-sgtl5000-y := imx-sgtl5000.o
-snd-soc-imx-spdif-y := imx-spdif.o
 snd-soc-imx-audmix-y := imx-audmix.o
 snd-soc-imx-hdmi-y := imx-hdmi.o
 snd-soc-imx-rpmsg-y := imx-rpmsg.o
@@ -76,7 +75,6 @@ snd-soc-imx-card-y := imx-card.o
 obj-$(CONFIG_SND_SOC_EUKREA_TLV320) += snd-soc-eukrea-tlv320.o
 obj-$(CONFIG_SND_SOC_IMX_ES8328) += snd-soc-imx-es8328.o
 obj-$(CONFIG_SND_SOC_IMX_SGTL5000) += snd-soc-imx-sgtl5000.o
-obj-$(CONFIG_SND_SOC_IMX_SPDIF) += snd-soc-imx-spdif.o
 obj-$(CONFIG_SND_SOC_IMX_AUDMIX) += snd-soc-imx-audmix.o
 obj-$(CONFIG_SND_SOC_IMX_HDMI) += snd-soc-imx-hdmi.o
 obj-$(CONFIG_SND_SOC_IMX_RPMSG) += snd-soc-imx-rpmsg.o

sound/soc/fsl/imx-spdif.c

-// SPDX-License-Identifier: GPL-2.0+
-//
-// Copyright (C) 2013 Freescale Semiconductor, Inc.
-
-#include <linux/module.h>
-#include <linux/of_platform.h>
-#include <sound/soc.h>
-
-struct imx_spdif_data {
-	struct snd_soc_dai_link dai;
-	struct snd_soc_card card;
-};
-
-static int imx_spdif_audio_probe(struct platform_device *pdev)
-{
-	struct device_node *spdif_np, *np = pdev->dev.of_node;
-	struct imx_spdif_data *data;
-	struct snd_soc_dai_link_component *comp;
-	int ret = 0;
-
-	spdif_np = of_parse_phandle(np, "spdif-controller", 0);
-	if (!spdif_np) {
-		dev_err(&pdev->dev, "failed to find spdif-controller\n");
-		ret = -EINVAL;
-		goto end;
-	}
-
-	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
-	comp = devm_kzalloc(&pdev->dev, sizeof(*comp), GFP_KERNEL);
-	if (!data || !comp) {
-		ret = -ENOMEM;
-		goto end;
-	}
-
-	/*
-	 * CPU == Platform
-	 * platform is using soc-generic-dmaengine-pcm
-	 */
-	data->dai.cpus		=
-	data->dai.platforms	= comp;
-	data->dai.codecs	= &snd_soc_dummy_dlc;
-
-	data->dai.num_cpus	= 1;
-	data->dai.num_codecs	= 1;
-	data->dai.num_platforms	= 1;
-
-	data->dai.name = "S/PDIF PCM";
-	data->dai.stream_name = "S/PDIF PCM";
-	data->dai.cpus->of_node = spdif_np;
-	data->dai.playback_only = true;
-	data->dai.capture_only = true;
-
-	if (of_property_read_bool(np, "spdif-out"))
-		data->dai.capture_only = false;
-
-	if (of_property_read_bool(np, "spdif-in"))
-		data->dai.playback_only = false;
-
-	if (data->dai.playback_only && data->dai.capture_only) {
-		dev_err(&pdev->dev, "no enabled S/PDIF DAI link\n");
-		goto end;
-	}
-
-	data->card.dev = &pdev->dev;
-	data->card.dai_link = &data->dai;
-	data->card.num_links = 1;
-	data->card.owner = THIS_MODULE;
-
-	ret = snd_soc_of_parse_card_name(&data->card, "model");
-	if (ret)
-		goto end;
-
-	ret = devm_snd_soc_register_card(&pdev->dev, &data->card);
-	if (ret)
-		dev_err_probe(&pdev->dev, ret, "snd_soc_register_card failed\n");
-
-end:
-	of_node_put(spdif_np);
-
-	return ret;
-}
-
-static const struct of_device_id imx_spdif_dt_ids[] = {
-	{ .compatible = "fsl,imx-audio-spdif", },
-	{ /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, imx_spdif_dt_ids);
-
-static struct platform_driver imx_spdif_driver = {
-	.driver = {
-		.name = "imx-spdif",
-		.pm = &snd_soc_pm_ops,
-		.of_match_table = imx_spdif_dt_ids,
-	},
-	.probe = imx_spdif_audio_probe,
-};
-
-module_platform_driver(imx_spdif_driver);
-
-MODULE_AUTHOR("Freescale Semiconductor, Inc.");
-MODULE_DESCRIPTION("Freescale i.MX S/PDIF machine driver");
-MODULE_LICENSE("GPL v2");
-MODULE_ALIAS("platform:imx-spdif");