Add Dip Switch as a core feature (#6140)

* Add Dip Switches as a core feature

* Add documentation for Dip Switch feature

* Update Preonic Rev3 to use new feature and remove custom matrix

* Apply suggestions from code review

Co-Authored-By: noroadsleft <18669334+noroadsleft@users.noreply.github.com>

* Remove custom matrix line completely

Rather than just disabling it

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* DIP changes

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Use better check for DIP Switch configuration

* Add to show features

* Add bitmask callback for dip switch

* Fix OLKB Boards dip switch config

* Update docs to include bitmask example

* Fix comments/documentation

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Fix issues with docs and use example from @tuzonghua

* Fix wording

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Fix example to use proper formatting

Bad, BAAAAAAD drashna!!!

* Handle dip switch initialization better

4 files changed, 113 insertions, 0 deletions

diff --git a/quantum/dip_switch.c b/quantum/dip_switch.c
new file mode 100644
index 000000000..3b5a8dadc
--- /dev/null
+++ b/quantum/dip_switch.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2018 Jack Humbert <jack.humb@gmail.com>
+ * Copyright 2019 Drashna Jaelre (Christopher Courtney) <drashna@live.com>
+ *
+ * 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/>.
+ */
+
+#include "dip_switch.h"
+
+// for memcpy
+#include <string.h>
+
+
+#if !defined(DIP_SWITCH_PINS)
+#   error "No DIP switch pads defined by DIP_SWITCH_PINS"
+#endif
+
+#define NUMBER_OF_DIP_SWITCHES (sizeof(dip_switch_pad)/sizeof(pin_t))
+static pin_t dip_switch_pad[] = DIP_SWITCH_PINS;
+static bool dip_switch_state[NUMBER_OF_DIP_SWITCHES] = { 0 };
+static bool last_dip_switch_state[NUMBER_OF_DIP_SWITCHES] = { 0 };
+
+
+__attribute__((weak))
+void dip_switch_update_user(uint8_t index, bool active) {}
+
+__attribute__((weak))
+void dip_switch_update_kb(uint8_t index, bool active) { dip_switch_update_user(index, active); }
+
+__attribute__((weak))
+void dip_switch_update_mask_user(uint32_t state) {}
+
+__attribute__((weak))
+void dip_switch_update_mask_kb(uint32_t state) { dip_switch_update_mask_user(state); }
+
+void dip_switch_init(void) {
+  for (uint8_t i = 0; i < NUMBER_OF_DIP_SWITCHES; i++) {
+    setPinInputHigh(dip_switch_pad[i]);
+  }
+  dip_switch_read(true);
+}
+
+
+void dip_switch_read(bool forced) {
+    bool has_dip_state_changed = false;
+    uint32_t dip_switch_mask = 0;
+
+    for (uint8_t i = 0; i < NUMBER_OF_DIP_SWITCHES; i++) {
+        dip_switch_state[i] = !readPin(dip_switch_pad[i]);
+        dip_switch_mask |= dip_switch_state[i] << i;
+        if (last_dip_switch_state[i] ^ dip_switch_state[i] || forced) {
+            has_dip_state_changed = true;
+            dip_switch_update_kb(i, dip_switch_state[i]);
+        }
+    }
+    if (has_dip_state_changed) {
+        dip_switch_update_mask_kb(dip_switch_mask);
+    }
+    memcpy(last_dip_switch_state, dip_switch_state, sizeof(&dip_switch_state));
+}
diff --git a/quantum/dip_switch.h b/quantum/dip_switch.h
new file mode 100644
index 000000000..61ef1cc19
--- /dev/null
+++ b/quantum/dip_switch.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2018 Jack Humbert <jack.humb@gmail.com>
+ * Copyright 2018 Drashna Jaelre (Christopher Courtney) <drashna@live.com>
+ *
+ * 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
+
+#include "quantum.h"
+
+void dip_switch_update_kb(uint8_t index, bool active);
+void dip_switch_update_user(uint8_t index, bool active);
+void dip_switch_update_mask_user(uint32_t state);
+void dip_switch_update_mask_kb(uint32_t state);
+
+void dip_switch_init(void);
+void dip_switch_read(bool forced);
diff --git a/quantum/quantum.c b/quantum/quantum.c
index 61e9003b7..85a03377f 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -967,6 +967,10 @@ void matrix_init_quantum() {
 #ifdef OUTPUT_AUTO_ENABLE
     set_output(OUTPUT_AUTO);
 #endif
+#ifdef DIP_SWITCH_ENABLE
+    dip_switch_init();
+#endif
+
     matrix_init_kb();
 }
 
@@ -1003,6 +1007,10 @@ void matrix_scan_quantum() {
     haptic_task();
 #endif
 
+#ifdef DIP_SWITCH_ENABLE
+    dip_switch_read(false);
+#endif
+
     matrix_scan_kb();
 }
 #if defined(BACKLIGHT_ENABLE) && (defined(BACKLIGHT_PIN) || defined(BACKLIGHT_PINS))
diff --git a/quantum/quantum.h b/quantum/quantum.h
index 066113590..f5ac97379 100644
--- a/quantum/quantum.h
+++ b/quantum/quantum.h
@@ -145,6 +145,11 @@ extern layer_state_t layer_state;
 #    include "oled_driver.h"
 #endif
 
+#ifdef DIP_SWITCH_ENABLE
+    #include "dip_switch.h"
+#endif
+
+
 // Function substitutions to ease GPIO manipulation
 #if defined(__AVR__)
 typedef uint8_t pin_t;