rpmsg: Create the rpmsg class in core instead of in rpmsg char

Migrate the creation of the rpmsg class from the rpmsg_char
to the core that the class is usable by the rpmsg_char and
the future rpmsg_ctrl module.

Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124102524.295783-3-arnaud.pouliquen@foss.st.com

drivers/rpmsg/rpmsg_char.c

@@ -27,11 +27,11 @@
 #include <uapi/linux/rpmsg.h>
 
 #include "rpmsg_char.h"
+#include "rpmsg_internal.h"
 
 #define RPMSG_DEV_MAX	(MINORMASK + 1)
 
 static dev_t rpmsg_major;
-static struct class *rpmsg_class;
 
 static DEFINE_IDA(rpmsg_ctrl_ida);
 static DEFINE_IDA(rpmsg_ept_ida);
@@ -550,17 +550,9 @@ static int rpmsg_chrdev_init(void)
 		return ret;
 	}
 
-	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
-	if (IS_ERR(rpmsg_class)) {
-		pr_err("failed to create rpmsg class\n");
-		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
-		return PTR_ERR(rpmsg_class);
-	}
-
 	ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
 	if (ret < 0) {
 		pr_err("failed to register rpmsg driver\n");
-		class_destroy(rpmsg_class);
 		unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 	}
 
@@ -571,7 +563,6 @@ postcore_initcall(rpmsg_chrdev_init);
 static void rpmsg_chrdev_exit(void)
 {
 	unregister_rpmsg_driver(&rpmsg_chrdev_driver);
-	class_destroy(rpmsg_class);
 	unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
 }
 module_exit(rpmsg_chrdev_exit);

drivers/rpmsg/rpmsg_core.c

@@ -20,6 +20,9 @@
 
 #include "rpmsg_internal.h"
 
+struct class *rpmsg_class;
+EXPORT_SYMBOL(rpmsg_class);
+
 /**
  * rpmsg_create_channel() - create a new rpmsg channel
  * using its name and address info.
@@ -662,10 +665,17 @@ static int __init rpmsg_init(void)
 {
 	int ret;
 
-	ret = bus_register(&rpmsg_bus);
-	if (ret)
-		pr_err("failed to register rpmsg bus: %d\n", ret);
+	rpmsg_class = class_create(THIS_MODULE, "rpmsg");
+	if (IS_ERR(rpmsg_class)) {
+		pr_err("failed to create rpmsg class\n");
+		return PTR_ERR(rpmsg_class);
+	}
 
+	ret = bus_register(&rpmsg_bus);
+	if (ret) {
+		pr_err("failed to register rpmsg bus: %d\n", ret);
+		class_destroy(rpmsg_class);
+	}
 	return ret;
 }
 postcore_initcall(rpmsg_init);
@@ -673,6 +683,7 @@ postcore_initcall(rpmsg_init);
 static void __exit rpmsg_fini(void)
 {
 	bus_unregister(&rpmsg_bus);
+	class_destroy(rpmsg_class);
 }
 module_exit(rpmsg_fini);
 

drivers/rpmsg/rpmsg_internal.h

@@ -18,6 +18,8 @@
 #define to_rpmsg_device(d) container_of(d, struct rpmsg_device, dev)
 #define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
 
+extern struct class *rpmsg_class;
+
 /**
  * struct rpmsg_device_ops - indirection table for the rpmsg_device operations
  * @create_channel:	create backend-specific channel, optional