Partially revert #18940 for Ploopy Thumb Trackball (#18943)

keyboards/ploopyco/trackball_thumb/rev1_001/config.h

@@ -0,0 +1,24 @@
+/* Copyright 2021 Colin Lam (Ploopy Corporation)
+ * Copyright 2020 Christopher Courtney, aka Drashna Jael're  (@drashna) <drashna@live.com>
+ * Copyright 2019 Sunjun Kim
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+// These pins are not broken out, and cannot be used normally.
+// They are set as output and pulled high, by default
+#define UNUSABLE_PINS \
+    { D1, D3, B4, B7, D6, C7, F6, F5, F3, F7 }

keyboards/ploopyco/trackball_thumb/trackball_thumb.c

@@ -188,6 +188,19 @@ void keyboard_pre_init_kb(void) {
     setPinInput(OPT_ENC1);
     setPinInput(OPT_ENC2);
 
+    /* Ground all output pins connected to ground. This provides additional
+     * pathways to ground. If you're messing with this, know this: driving ANY
+     * of these pins high will cause a short. On the MCU. Ka-blooey.
+     */
+#ifdef UNUSABLE_PINS
+    const pin_t unused_pins[] = UNUSABLE_PINS;
+
+    for (uint8_t i = 0; i < (sizeof(unused_pins) / sizeof(pin_t)); i++) {
+        setPinOutput(unused_pins[i]);
+        writePinLow(unused_pins[i]);
+    }
+#endif
+
     // This is the debug LED.
 #if defined(DEBUG_LED_PIN)
     setPinOutput(DEBUG_LED_PIN);