pps: generators: pps_gen_parport: Switch to use module_parport_driver()

Switch to use module_parport_driver() to reduce boilerplate code.

Note, it doesn't matter when we check the module parameter. If it was
writable we even would have more flexibility of changing it at runtime
(when built-in the kernel) after this patch.

Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220210134943.62026-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pps/generators/pps_gen_parport.c

@@ -20,8 +20,6 @@
 #include <linux/hrtimer.h>
 #include <linux/parport.h>
 
-#define DRVDESC "parallel port PPS signal generator"
-
 #define SIGNAL		0
 #define NO_SIGNAL	PARPORT_CONTROL_STROBE
 
@@ -180,6 +178,11 @@ static void parport_attach(struct parport *port)
 {
 	struct pardev_cb pps_cb;
 
+	if (send_delay > SEND_DELAY_MAX) {
+		pr_err("delay value should be not greater then %d\n", SEND_DELAY_MAX);
+		return;
+	}
+
 	if (attached) {
 		/* we already have a port */
 		return;
@@ -231,39 +234,8 @@ static struct parport_driver pps_gen_parport_driver = {
 	.detach = parport_detach,
 	.devmodel = true,
 };
-
-/* module staff */
-
-static int __init pps_gen_parport_init(void)
-{
-	int ret;
-
-	pr_info(DRVDESC "\n");
-
-	if (send_delay > SEND_DELAY_MAX) {
-		pr_err("delay value should be not greater"
-				" then %d\n", SEND_DELAY_MAX);
-		return -EINVAL;
-	}
-
-	ret = parport_register_driver(&pps_gen_parport_driver);
-	if (ret) {
-		pr_err("unable to register with parport\n");
-		return ret;
-	}
-
-	return  0;
-}
-
-static void __exit pps_gen_parport_exit(void)
-{
-	parport_unregister_driver(&pps_gen_parport_driver);
-	pr_info("hrtimer avg error is %ldns\n", hrtimer_error);
-}
-
-module_init(pps_gen_parport_init);
-module_exit(pps_gen_parport_exit);
+module_parport_driver(pps_gen_parport_driver);
 
 MODULE_AUTHOR("Alexander Gordeev <lasaine@lvk.cs.msu.su>");
-MODULE_DESCRIPTION(DRVDESC);
+MODULE_DESCRIPTION("parallel port PPS signal generator");
 MODULE_LICENSE("GPL");