dsp56k: make dsp56k_class a static const structure

Now that the driver core allows for struct class to be in read-only
memory, move the dsp56k_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620143751.578239-11-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ivanorlov2206

drivers/char/dsp56k.c

@@ -101,7 +101,9 @@ static struct dsp56k_device {
 	int tx_wsize, rx_wsize;
 } dsp56k;
 
-static struct class *dsp56k_class;
+static const struct class dsp56k_class = {
+	.name = "dsp56k",
+};
 
 static int dsp56k_reset(void)
 {
@@ -493,7 +495,7 @@ static const char banner[] __initconst = KERN_INFO "DSP56k driver installed\n";
 
 static int __init dsp56k_init_driver(void)
 {
-	int err = 0;
+	int err;
 
 	if(!MACH_IS_ATARI || !ATARIHW_PRESENT(DSP56K)) {
 		printk("DSP56k driver: Hardware not present\n");
@@ -504,12 +506,10 @@ static int __init dsp56k_init_driver(void)
 		printk("DSP56k driver: Unable to register driver\n");
 		return -ENODEV;
 	}
-	dsp56k_class = class_create("dsp56k");
-	if (IS_ERR(dsp56k_class)) {
-		err = PTR_ERR(dsp56k_class);
+	err = class_register(&dsp56k_class);
+	if (err)
 		goto out_chrdev;
-	}
-	device_create(dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
+	device_create(&dsp56k_class, NULL, MKDEV(DSP56K_MAJOR, 0), NULL,
 		      "dsp56k");
 
 	printk(banner);
@@ -524,8 +524,8 @@ module_init(dsp56k_init_driver);
 
 static void __exit dsp56k_cleanup_driver(void)
 {
-	device_destroy(dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
-	class_destroy(dsp56k_class);
+	device_destroy(&dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
+	class_unregister(&dsp56k_class);
 	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
 }
 module_exit(dsp56k_cleanup_driver);