Create a new sound card to access MICFIL based on rpmsg channel

Merge series from Chancel Liu <[e-mail]>:

At a previous time, we have successfully created a virtual sound card
based on rpmsg. The sound card works under this mechanism Cortex-A core
tells the Cortex-M core the format, rate, channel, .etc configuration
of the PCM parameters and Cortex-M controls real hardware devices such
as SAI and DMA. From the view of Linux side, the sound card is bound to
a rpmsg channel through which it can access SAI.

Here these patches are introduced to create a new virtual sound card to
access MICFIL based on a new created rpmsg channel. It's easy to create
a new rpmsg channel for MICFIL through rpmsg name service announcment.
Also the other ASoC components bound to this rpmsg MICFIL sound card
will be registered with these patches.

If other sound cards using different hardware devices needs to be
created over rpmsg in the future, these patches can be referred.

Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml

···
 
 description: |
   fsl_rpmsg is a virtual audio device. Mapping to real hardware devices
-  are SAI, DMA controlled by Cortex M core. What we see from Linux
-  side is a device which provides audio service by rpmsg channel.
+  are SAI, MICFIL, DMA controlled by Cortex M core. What we see from
+  Linux side is a device which provides audio service by rpmsg channel.
+  We can create different sound cards which access different hardwares
+  such as SAI, MICFIL, .etc through building rpmsg channels between
+  Cortex-A and Cortex-M.
 
 properties:
   compatible:
···
       This is a boolean property. If present, the receiving function
       will be enabled.
 
+  fsl,rpmsg-channel-name:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      A string property to assign rpmsg channel this sound card sits on.
+      This property can be omitted if there is only one sound card and it sits
+      on "rpmsg-audio-channel".
+    enum:
+      - rpmsg-audio-channel
+      - rpmsg-micfil-channel
+
 required:
   - compatible
   - model
···
                  <&clk IMX8MN_AUDIO_PLL2_OUT>;
         clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
     };
+
+  - |
+    #include <dt-bindings/clock/imx8mm-clock.h>
+
+    rpmsg_micfil: audio-controller {
+        compatible = "fsl,imx8mm-rpmsg-audio";
+        model = "micfil-audio";
+        fsl,rpmsg-channel-name = "rpmsg-micfil-channel";
+        fsl,enable-lpa;
+        fsl,rpmsg-in;
+        clocks = <&clk IMX8MM_CLK_PDM_IPG>,
+                 <&clk IMX8MM_CLK_PDM_ROOT>,
+                 <&clk IMX8MM_CLK_SDMA3_ROOT>,
+                 <&clk IMX8MM_AUDIO_PLL1_OUT>,
+                 <&clk IMX8MM_AUDIO_PLL2_OUT>;
+        clock-names = "ipg", "mclk", "dma", "pll8k", "pll11k";
+    };
+
+...

sound/soc/fsl/fsl_rpmsg.c

···
 	.playback = {
 		.stream_name = "CPU-Playback",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = SNDRV_PCM_RATE_KNOT,
 		.formats = FSL_RPMSG_FORMATS,
 	},
 	.capture = {
 		.stream_name = "CPU-Capture",
 		.channels_min = 2,
-		.channels_max = 2,
+		.channels_max = 32,
 		.rates = SNDRV_PCM_RATE_KNOT,
 		.formats = FSL_RPMSG_FORMATS,
 	},
···
 
 	rpmsg->card_pdev = platform_device_register_data(&pdev->dev,
 							 "imx-audio-rpmsg",
-							 PLATFORM_DEVID_NONE,
+							 PLATFORM_DEVID_AUTO,
 							 NULL,
 							 0);
 	if (IS_ERR(rpmsg->card_pdev)) {

sound/soc/fsl/imx-audio-rpmsg.c

···
 	/* Register platform driver for rpmsg routine */
 	data->rpmsg_pdev = platform_device_register_data(&rpdev->dev,
 							 IMX_PCM_DRV_NAME,
-							 PLATFORM_DEVID_NONE,
+							 PLATFORM_DEVID_AUTO,
 							 NULL, 0);
 	if (IS_ERR(data->rpmsg_pdev)) {
 		dev_err(&rpdev->dev, "failed to register rpmsg platform.\n");
···
 
 static struct rpmsg_device_id imx_audio_rpmsg_id_table[] = {
 	{ .name	= "rpmsg-audio-channel" },
+	{ .name = "rpmsg-micfil-channel" },
 	{ },
 };
 

sound/soc/fsl/imx-pcm-rpmsg.c

···
 		msg->s_msg.param.channels = RPMSG_CH_STEREO;
 		break;
 	default:
-		ret = -EINVAL;
+		msg->s_msg.param.channels = params_channels(params);
 		break;
 	}
 
···
 	info->rpdev = container_of(pdev->dev.parent, struct rpmsg_device, dev);
 	info->dev = &pdev->dev;
 	/* Setup work queue */
-	info->rpmsg_wq = alloc_ordered_workqueue("rpmsg_audio",
+	info->rpmsg_wq = alloc_ordered_workqueue(info->rpdev->id.name,
 						 WQ_HIGHPRI |
 						 WQ_UNBOUND |
 						 WQ_FREEZABLE);
···
 	if (ret)
 		goto fail;
 
-	component = snd_soc_lookup_component(&pdev->dev, IMX_PCM_DRV_NAME);
+	component = snd_soc_lookup_component(&pdev->dev, NULL);
 	if (!component) {
 		ret = -EINVAL;
 		goto fail;
 	}
+
+	/* platform component name is used by machine driver to link with */
+	component->name = info->rpdev->id.name;
+
 #ifdef CONFIG_DEBUG_FS
 	component->debugfs_prefix = "rpmsg";
 #endif

sound/soc/fsl/imx-rpmsg.c

···
 	struct platform_device *rpmsg_pdev = to_platform_device(dev);
 	struct device_node *np = rpmsg_pdev->dev.of_node;
 	struct of_phandle_args args;
+	const char *platform_name;
 	struct imx_rpmsg *data;
 	int ret = 0;
 
···
 	}
 
 	data->dai.cpus->dai_name = dev_name(&rpmsg_pdev->dev);
-	data->dai.platforms->name = IMX_PCM_DRV_NAME;
+	if (!of_property_read_string(np, "fsl,rpmsg-channel-name", &platform_name))
+		data->dai.platforms->name = platform_name;
+	else
+		data->dai.platforms->name = "rpmsg-audio-channel";
 	data->dai.playback_only = true;
 	data->dai.capture_only = true;
 	data->card.num_links = 1;