From 932491f75629ab2e3f4acbfd1a7e16d42f8bc351 Mon Sep 17 00:00:00 2001
From: Mark Farrugia <mark.farrugia@fiberdyne.com.au>
Date: Fri, 2 Nov 2018 14:49:24 +1100
Subject: Transform AVIRT into platform driver

Like aloop, we need to be able to find AVIRT by-path as
platform-snd_avirt.0. The 4a-mixer uses this method to find cards.

Signed-off-by: Mark Farrugia <mark.farrugia@fiberdyne.com.au>
---
 core.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++-------------------
 core.h |  1 +
 2 files changed, 64 insertions(+), 25 deletions(-)

diff --git a/core.c b/core.c
index 4645f06..41cc555 100644
--- a/core.c
+++ b/core.c
@@ -11,6 +11,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <sound/initval.h>
+#include <linux/platform_device.h>
 
 #include "core.h"
 
@@ -439,16 +440,63 @@ struct snd_avirt_stream *snd_avirt_stream_find_by_device(unsigned int device)
 	return NULL;
 }
 
+static int snd_avirt_core_probe(struct platform_device *devptr)
+{
+	int err;
+
+	// Create the card instance
+	err = snd_card_new(&devptr->dev, SNDRV_DEFAULT_IDX1, "avirt",
+			   THIS_MODULE, 0, &core.card);
+	if (err < 0) {
+		D_ERRORK("Failed to create sound card");
+		return err;
+	}
+
+	strncpy(core.card->driver, "avirt-alsa-dev", 16);
+	strncpy(core.card->shortname, "avirt", 32);
+	strncpy(core.card->longname, "A virtual sound card driver for ALSA",
+		80);
+
+	return 0;
+}
+
+static int snd_avirt_core_remove(struct platform_device *devptr)
+{
+	snd_card_free(core.card);
+
+	return 0;
+}
+
+static struct platform_driver snd_avirt_driver = {
+	.probe = snd_avirt_core_probe,
+	.remove = snd_avirt_core_remove,
+	.driver =
+		{
+			.name = SND_AVIRT_DRIVER,
+		},
+};
+
 /**
- * core_init - Initialize the kernel module
+ * snd_avirt_core_init - Initialize the kernel module
  */
-static int __init core_init(void)
+static int __init snd_avirt_core_init(void)
 {
 	int err;
 
 	D_INFOK("Alsa Virtual Sound Driver avirt-%d.%d.%d", core.version[0],
 		core.version[1], core.version[2]);
 
+	err = platform_driver_register(&snd_avirt_driver);
+	if (err < 0)
+		return err;
+
+	core.plat_dev =
+		platform_device_register_simple(SND_AVIRT_DRIVER, 0, NULL, 0);
+	if (IS_ERR(core.plat_dev)) {
+		err = PTR_ERR(core.plat_dev);
+		goto exit_platform_device;
+	}
+
 	core.class = class_create(THIS_MODULE, SND_AVIRT_DRIVER);
 	if (IS_ERR(core.class)) {
 		D_ERRORK("No udev support");
@@ -461,54 +509,44 @@ static int __init core_init(void)
 		goto exit_class;
 	}
 
-	// Create the card instance
-	err = snd_card_new(core.dev, SNDRV_DEFAULT_IDX1, "avirt", THIS_MODULE,
-			   0, &core.card);
-	if (err < 0) {
-		D_ERRORK("Failed to create sound card");
-		goto exit_class_container;
-	}
-
-	strncpy(core.card->driver, "avirt-alsa-dev", 16);
-	strncpy(core.card->shortname, "avirt", 32);
-	strncpy(core.card->longname, "A virtual sound card driver for ALSA",
-		80);
-
 	snd_avirt_audiopath_kset =
 		kset_create_and_add("audiopaths", NULL, &core.dev->kobj);
 	if (!snd_avirt_audiopath_kset) {
 		err = -ENOMEM;
-		goto exit_snd_card;
+		goto exit_class_container;
 	}
 
 	err = snd_avirt_configfs_init(&core);
 	if (err < 0)
-		goto exit_snd_card;
+		goto exit_kset;
 
 	return 0;
 
-exit_snd_card:
-	snd_card_free(core.card);
+exit_kset:
+	kset_unregister(snd_avirt_audiopath_kset);
 exit_class_container:
 	device_destroy(core.class, 0);
 exit_class:
 	class_destroy(core.class);
+exit_platform_device:
+	platform_device_unregister(core.plat_dev);
+	platform_driver_unregister(&snd_avirt_driver);
 
 	return err;
 }
 
 /**
- * core_exit - Destroy the kernel module
+ * snd_avirt_core_exit - Destroy the kernel module
  */
-static void __exit core_exit(void)
+static void __exit snd_avirt_core_exit(void)
 {
 	snd_avirt_configfs_exit(&core);
-
 	kset_unregister(snd_avirt_audiopath_kset);
-	snd_card_free(core.card);
 	device_destroy(core.class, 0);
 	class_destroy(core.class);
+	platform_device_unregister(core.plat_dev);
+	platform_driver_unregister(&snd_avirt_driver);
 }
 
-module_init(core_init);
-module_exit(core_exit);
+module_init(snd_avirt_core_init);
+module_exit(snd_avirt_core_exit);
diff --git a/core.h b/core.h
index 61a78e9..fe2aaab 100644
--- a/core.h
+++ b/core.h
@@ -21,6 +21,7 @@ struct snd_avirt_core {
 	struct snd_card *card;
 	struct device *dev;
 	struct class *class;
+	struct platform_device *plat_dev;
 	struct config_group *stream_group;
 	unsigned int stream_count;
 	bool streams_sealed;
-- 
cgit 1.2.3-korg