HID: use standard debug APIs

The custom "debug" module parameter is fairly inflexible.
It can only manage debugging for all calls dbg_hid() at the same time.

Furthermore it creates a mismatch between calls to hid_dbg() which can
be managed by CONFIG_DYNAMIC_DEBUG and dbg_hid() which is managed by the
module parameter.

Furthermore the change to pr_debug() allows the debugging statements to
be completely compiled-out if desired.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Bastien Nocera <hadess@hadess.net>
Link: https://lore.kernel.org/r/20221223-hid-dbg-v1-1-5dcf8794f7f9@weissschuh.netSigned-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/hid-core.c

@@ -41,11 +41,6 @@
 
 #define DRIVER_DESC "HID core driver"
 
-int hid_debug = 0;
-module_param_named(debug, hid_debug, int, 0600);
-MODULE_PARM_DESC(debug, "toggle HID debugging messages");
-EXPORT_SYMBOL_GPL(hid_debug);
-
 static int hid_ignore_special_drivers = 0;
 module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
 MODULE_PARM_DESC(ignore_special_drivers, "Ignore any special drivers and handle all devices by generic driver");
@@ -2910,10 +2905,6 @@ static int __init hid_init(void)
 {
 	int ret;
 
-	if (hid_debug)
-		pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
-			"debugfs is now used for inspecting the device (report descriptor, reports)\n");
-
 	ret = bus_register(&hid_bus_type);
 	if (ret) {
 		pr_err("can't register hid bus\n");

include/linux/hid.h

@@ -870,8 +870,6 @@ extern bool hid_is_usb(const struct hid_device *hdev);
 
 /* HID core API */
 
-extern int hid_debug;
-
 extern bool hid_ignore(struct hid_device *);
 extern int hid_add_device(struct hid_device *);
 extern void hid_destroy_device(struct hid_device *);
@@ -1179,11 +1177,7 @@ int hid_pidff_init(struct hid_device *hid);
 #define hid_pidff_init NULL
 #endif
 
-#define dbg_hid(fmt, ...)						\
-do {									\
-	if (hid_debug)							\
-		printk(KERN_DEBUG "%s: " fmt, __FILE__, ##__VA_ARGS__);	\
-} while (0)
+#define dbg_hid(fmt, ...) pr_debug("%s: " fmt, __FILE__, ##__VA_ARGS__)
 
 #define hid_err(hid, fmt, ...)				\
 	dev_err(&(hid)->dev, fmt, ##__VA_ARGS__)