quoted

+
+    case 3:
+        if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+            elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
+            elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
+            elantech_ps2_command(psmouse, NULL, reg) ||
+            elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
+            rc = -1;
+        }

Prefer to remove these big brace ?
also with "case 1, case 2 "?

Just wondering What's wrong with this piece of code and what do you
sugguest to improve it?