staging: most: enable configfs support

This patch enables the configfs functionality of the driver by
registering the configfs subsystems and compiling the configfs
part of the sources.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/Kconfig

 # SPDX-License-Identifier: GPL-2.0
 menuconfig MOST
         tristate "MOST support"
-	depends on HAS_DMA
+	depends on HAS_DMA && CONFIGFS_FS
         default n
         ---help---
 	  Say Y here if you want to enable MOST support.

drivers/staging/most/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_MOST) += most_core.o
 most_core-y := core.o
+most_core-y += configfs.o
 ccflags-y += -I $(srctree)/drivers/staging/
 
 obj-$(CONFIG_MOST_CDEV)	+= cdev/

drivers/staging/most/cdev/cdev.c

@@ -527,8 +527,13 @@ static int __init mod_init(void)
 	err = most_register_component(&comp.cc);
 	if (err)
 		goto free_cdev;
+	err = most_register_configfs_subsys(&comp.cc);
+	if (err)
+		goto deregister_comp;
 	return 0;
 
+deregister_comp:
+	most_deregister_component(&comp.cc);
 free_cdev:
 	unregister_chrdev_region(comp.devno, CHRDEV_REGION_SIZE);
 dest_ida:
@@ -543,6 +548,7 @@ static void __exit mod_exit(void)
 
 	pr_info("exit module\n");
 
+	most_deregister_configfs_subsys(&comp.cc);
 	most_deregister_component(&comp.cc);
 
 	list_for_each_entry_safe(c, tmp, &channel_list, list) {

drivers/staging/most/core.c

@@ -1765,7 +1765,7 @@ static int __init most_init(void)
 		err = -ENOMEM;
 		goto err_unregister_driver;
 	}
-
+	configfs_init();
 	return 0;
 
 err_unregister_driver:

drivers/staging/most/sound/sound.c

@@ -790,16 +790,25 @@ static struct core_component comp = {
 
 static int __init audio_init(void)
 {
+	int ret;
+
 	pr_info("init()\n");
 
 	INIT_LIST_HEAD(&adpt_list);
 
-	return most_register_component(&comp);
+	ret = most_register_component(&comp);
+	if (ret)
+		pr_err("Failed to register %s\n", comp.name);
+	ret = most_register_configfs_subsys(&comp);
+	if (ret)
+		pr_err("Failed to register %s configfs subsys\n", comp.name);
+	return ret;
 }
 
 static void __exit audio_exit(void)
 {
 	pr_info("exit()\n");
+	most_deregister_configfs_subsys(&comp);
 	most_deregister_component(&comp);
 }