From f2a8a13dbad220cfb0dfbd72a90492a15a2e58bb Mon Sep 17 00:00:00 2001
From: dexter93 <d3xter93@gmail.com>
Date: Thu, 8 Dec 2022 18:09:01 +0200
Subject: [PATCH] Core: Support inverted scan logic for optical switches
 (#19053)

---
 data/mappings/info_config.hjson      |  1 +
 data/schemas/keyboard.jsonschema     |  1 +
 docs/porting_your_keyboard_to_qmk.md | 12 ++++++++++++
 quantum/matrix.c                     | 10 ++++++----
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/data/mappings/info_config.hjson b/data/mappings/info_config.hjson
index 8f7b34d41a..414439d6e7 100644
--- a/data/mappings/info_config.hjson
+++ b/data/mappings/info_config.hjson
@@ -55,6 +55,7 @@
     "LED_MATRIX_VAL_STEP": {"info_key": "led_matrix.val_steps", "value_type": "int"},
     "LED_MATRIX_SPD_STEP": {"info_key": "led_matrix.speed_steps", "value_type": "int"},
     "MATRIX_HAS_GHOST": {"info_key": "matrix_pins.ghost", "value_type": "bool"},
+    "MATRIX_INPUT_PRESSED_STATE": {"info_key": "matrix_pins.input_pressed_state", "value_type": "int"},
     "MATRIX_IO_DELAY": {"info_key": "matrix_pins.io_delay", "value_type": "int"},
     "MOUSEKEY_DELAY": {"info_key": "mousekey.delay", "value_type": "int"},
     "MOUSEKEY_INTERVAL": {"info_key": "mousekey.interval", "value_type": "int"},
diff --git a/data/schemas/keyboard.jsonschema b/data/schemas/keyboard.jsonschema
index 5c0c23c2b1..7844bfd579 100644
--- a/data/schemas/keyboard.jsonschema
+++ b/data/schemas/keyboard.jsonschema
@@ -304,6 +304,7 @@
                 "custom": {"type": "boolean"},
                 "custom_lite": {"type": "boolean"},
                 "ghost": {"type": "boolean"},
+                "input_pressed_state": {"$ref": "qmk.definitions.v1#/unsigned_int"},
                 "io_delay": {"$ref": "qmk.definitions.v1#/unsigned_int"},
                 "direct": {
                     "type": "array",
diff --git a/docs/porting_your_keyboard_to_qmk.md b/docs/porting_your_keyboard_to_qmk.md
index 484d079ea6..05054e25c7 100644
--- a/docs/porting_your_keyboard_to_qmk.md
+++ b/docs/porting_your_keyboard_to_qmk.md
@@ -94,6 +94,18 @@ The next section of the `info` file deals with your keyboard's matrix. The first
 
 The size of the `matrix_pins.cols` and `matrix_pins.rows` arrays infer the size of the matrix (previously `MATRIX_ROWS` and `MATRIX_COLS`). 
 
+## Configuration Options
+
+To invert the keypress logic, configure `input_pressed_state`:
+
+```json
+    "matrix_pins": {
+        "input_pressed_state": 1,
+},
+```
+
+This configures state of the GPIO pins when the key is pressed - `1` for high, `0` for low. Default value is `0`.
+
 Finally, you can specify the direction your diodes point. This can be `COL2ROW` or `ROW2COL`.
 
 ```json
diff --git a/quantum/matrix.c b/quantum/matrix.c
index db683104ed..0de65c6cdd 100644
--- a/quantum/matrix.c
+++ b/quantum/matrix.c
@@ -46,6 +46,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #    define SPLIT_MUTABLE_COL const
 #endif
 
+#ifndef MATRIX_INPUT_PRESSED_STATE
+#    define MATRIX_INPUT_PRESSED_STATE 0
+#endif
+
 #ifdef DIRECT_PINS
 static SPLIT_MUTABLE pin_t direct_pins[ROWS_PER_HAND][MATRIX_COLS] = DIRECT_PINS;
 #elif (DIODE_DIRECTION == ROW2COL) || (DIODE_DIRECTION == COL2ROW)
@@ -93,7 +97,7 @@ static inline void setPinInputHigh_atomic(pin_t pin) {
 
 static inline uint8_t readMatrixPin(pin_t pin) {
     if (pin != NO_PIN) {
-        return readPin(pin);
+        return (readPin(pin) == MATRIX_INPUT_PRESSED_STATE) ? 0 : 1;
     } else {
         return 1;
     }
@@ -121,9 +125,7 @@ __attribute__((weak)) void matrix_read_cols_on_row(matrix_row_t current_matrix[]
     matrix_row_t row_shifter = MATRIX_ROW_SHIFTER;
     for (uint8_t col_index = 0; col_index < MATRIX_COLS; col_index++, row_shifter <<= 1) {
         pin_t pin = direct_pins[current_row][col_index];
-        if (pin != NO_PIN) {
-            current_row_value |= readPin(pin) ? 0 : row_shifter;
-        }
+        current_row_value |= readMatrixPin(pin) ? 0 : row_shifter;
     }
 
     // Update the matrix