HID: apple: Option to swap only left side mod keys

On the Keychron K8 keyboard, and probably others, the right side keys
should not be swapped to maintain PC layout.

Swapping the right side keys moves 'Super' before 'Alt gr' which is not
intended by the default Keychron layout or the ISO layout.
Signed-off-by: Lasse Brun <bruners@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-apple.c

@@ -58,7 +58,7 @@ static unsigned int swap_opt_cmd;
 module_param(swap_opt_cmd, uint, 0644);
 MODULE_PARM_DESC(swap_opt_cmd, "Swap the Option (\"Alt\") and Command (\"Flag\") keys. "
 		"(For people who want to keep Windows PC keyboard muscle memory. "
-		"[0] = as-is, Mac layout. 1 = swapped, Windows layout.)");
+		"[0] = as-is, Mac layout. 1 = swapped, Windows layout., 2 = swapped, Swap only left side)");
 
 static unsigned int swap_ctrl_cmd;
 module_param(swap_ctrl_cmd, uint, 0644);
@@ -319,6 +319,12 @@ static const struct apple_key_translation swapped_option_cmd_keys[] = {
 	{ }
 };
 
+static const struct apple_key_translation swapped_option_cmd_left_keys[] = {
+	{ KEY_LEFTALT,	KEY_LEFTMETA },
+	{ KEY_LEFTMETA,	KEY_LEFTALT },
+	{ }
+};
+
 static const struct apple_key_translation swapped_ctrl_cmd_keys[] = {
 	{ KEY_LEFTCTRL,	KEY_LEFTMETA },
 	{ KEY_LEFTMETA,	KEY_LEFTCTRL },
@@ -416,7 +422,10 @@ static int hidinput_apple_event(struct hid_device *hid, struct input_dev *input,
 	}
 
 	if (swap_opt_cmd) {
-		trans = apple_find_translation(swapped_option_cmd_keys, code);
+		if (swap_opt_cmd == 2)
+			trans = apple_find_translation(swapped_option_cmd_left_keys, code);
+		else
+			trans = apple_find_translation(swapped_option_cmd_keys, code);
 
 		if (trans)
 			code = trans->to;