NULL
 };
 
+static bool matches_pnp_id(struct psmouse *psmouse, const char * const ids[])
+{
+       int i;
+
+       if (!strncmp(psmouse->ps2dev.serio->firmware_id, "PNP:", 4))
+               for (i = 0; ids[i]; i++)
+                       if (strstr(psmouse->ps2dev.serio->firmware_id, ids[i]))
+                               return true;
+
+       return false;
+}
+
 /*****************************************************************************
  *     Synaptics communications functions
  ****************************************************************************/
 
        if (SYN_CAP_CLICKPAD(priv->ext_cap_0c)) {
                __set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
-               /* See if this buttonpad has a top button area */
-               if (!strncmp(psmouse->ps2dev.serio->firmware_id, "PNP:", 4)) {
-                       for (i = 0; topbuttonpad_pnp_ids[i]; i++) {
-                               if (strstr(psmouse->ps2dev.serio->firmware_id,
-                                          topbuttonpad_pnp_ids[i])) {
-                                       __set_bit(INPUT_PROP_TOPBUTTONPAD,
-                                                 dev->propbit);
-                                       break;
-                               }
-                       }
-               }
+               if (matches_pnp_id(psmouse, topbuttonpad_pnp_ids))
+                       __set_bit(INPUT_PROP_TOPBUTTONPAD, dev->propbit);
                /* Clickpads report only left button */
                __clear_bit(BTN_RIGHT, dev->keybit);
                __clear_bit(BTN_MIDDLE, dev->keybit);