HID: wacom: Refactor button-to-key translation into function

This just centralizes the logic used in both wacom_setup_numbered_buttons
and wacom_report_numbered_buttons so that they don't drift out of sync.
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_wac.c

@@ -2769,17 +2769,29 @@ int wacom_setup_touch_input_capabilities(struct input_dev *input_dev,
 	return 0;
 }
 
+static int wacom_numbered_button_to_key(int n)
+{
+	if (n < 10)
+		return BTN_0 + n;
+	else if (n < 16)
+		return BTN_A + (n-10);
+	else if (n < 18)
+		return BTN_BASE + (n-16);
+	else
+		return 0;
+}
+
 static void wacom_setup_numbered_buttons(struct input_dev *input_dev,
 				int button_count)
 {
 	int i;
 
-	for (i = 0; i < button_count && i < 10; i++)
-		__set_bit(BTN_0 + i, input_dev->keybit);
-	for (i = 10; i < button_count && i < 16; i++)
-		__set_bit(BTN_A + (i-10), input_dev->keybit);
-	for (i = 16; i < button_count && i < 18; i++)
-		__set_bit(BTN_BASE + (i-16), input_dev->keybit);
+	for (i = 0; i < button_count; i++) {
+		int key = wacom_numbered_button_to_key(i);
+
+		if (key)
+			__set_bit(key, input_dev->keybit);
+	}
 }
 
 static void wacom_24hd_update_leds(struct wacom *wacom, int mask, int group)
@@ -2881,12 +2893,12 @@ static void wacom_report_numbered_buttons(struct input_dev *input_dev,
 	for (i = 0; i < wacom->led.count; i++)
 		wacom_update_led(wacom,  button_count, mask, i);
 
-	for (i = 0; i < button_count && i < 10; i++)
-		input_report_key(input_dev, BTN_0 + i, mask & (1 << i));
-	for (i = 10; i < button_count && i < 16; i++)
-		input_report_key(input_dev, BTN_A + (i-10), mask & (1 << i));
-	for (i = 16; i < button_count && i < 18; i++)
-		input_report_key(input_dev, BTN_BASE + (i-16), mask & (1 << i));
+	for (i = 0; i < button_count; i++) {
+		int key = wacom_numbered_button_to_key(i);
+
+		if (key)
+			input_report_key(input_dev, key, mask & (1 << i));
+	}
 }
 
 int wacom_setup_pad_input_capabilities(struct input_dev *input_dev,