[Keyboard] Add Torn keyboard (#10207)

* Add Torn keyboard

* Apply suggestions from code review

Co-authored-by: Nick Brassel <nick@tzarc.org>

* Remove via json file

* Add mcp23081_pin_t

* Apply suggestions from code review

Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Drashna Jaelre <drashna@live.com>

* Apply suggestions from code review

Co-authored-by: Ryan <fauxpark@gmail.com>

Co-authored-by: Richard Titmuss <richardt@spotify.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>
Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>
Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Ryan <fauxpark@gmail.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/keyboards/torn/matrix.c b/keyboards/torn/matrix.c
new file mode 100644
index 000000000..dd7fa1e2e
--- /dev/null
+++ b/keyboards/torn/matrix.c
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2020 Richard Titmuss (richard.titmuss@gmail.com)
+ * Copyright 2012-2018 Jun Wako, Jack Humbert, Yiancar
+ *
+ * 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 QMK_KEYBOARD_H
+#include "mcp23018.h"
+
+#define SPLIT_MATRIX_COLS (MATRIX_COLS / 2)
+#define SECONDARY_ROW_OFFSET (MATRIX_ROWS / 2)
+
+typedef uint16_t mcp23018_pin_t;
+
+static const pin_t          row_pins[MATRIX_ROWS]                 = MATRIX_ROW_PINS;
+static const pin_t          col_pins[SPLIT_MATRIX_COLS]           = MATRIX_COL_PINS;
+static const mcp23018_pin_t secondary_row_pins[MATRIX_ROWS]       = SECONDARY_ROW_PINS;
+static const mcp23018_pin_t secondary_col_pins[SPLIT_MATRIX_COLS] = SECONDARY_COL_PINS;
+
+static void select_row(uint8_t row) {
+    setPinOutput(row_pins[row]);
+    writePinLow(row_pins[row]);
+}
+
+static void unselect_row(uint8_t row) { setPinInputHigh(row_pins[row]); }
+
+static void unselect_rows(void) {
+    for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
+        setPinInputHigh(row_pins[x]);
+    }
+}
+
+static void select_secondary_row(uint8_t row) {
+    uint8_t gpioa = 0xFF & ~secondary_row_pins[row];
+    mcp23018_writeReg(GPIOA, &gpioa, 1);
+}
+
+static void init_pins(void) {
+    unselect_rows();
+    for (uint8_t x = 0; x < SPLIT_MATRIX_COLS; x++) {
+        setPinInputHigh(col_pins[x]);
+    }
+}
+
+static matrix_row_t read_cols(void) {
+    matrix_row_t state = 0;
+
+    // For each col...
+    for (uint8_t col_index = 0; col_index < SPLIT_MATRIX_COLS; col_index++) {
+        // Select the col pin to read (active low)
+        uint8_t pin_state = readPin(col_pins[col_index]);
+
+        // Populate the matrix row with the state of the col pin
+        state |= pin_state ? 0 : (MATRIX_ROW_SHIFTER << col_index);
+    }
+
+    return state;
+}
+
+static matrix_row_t read_secondary_cols(void) {
+    matrix_row_t state = 0;
+
+    uint8_t mcp23018_pin_state[2];
+    if (mcp23018_readReg(GPIOA, mcp23018_pin_state, 2)) {
+        return 0;
+    }
+
+    uint16_t pins = mcp23018_pin_state[0] | (mcp23018_pin_state[1] << 8);
+
+    for (uint8_t col_index = 0; col_index < SPLIT_MATRIX_COLS; col_index++) {
+        uint16_t pin_state = pins & (secondary_col_pins[col_index]);
+        state |= pin_state ? 0 : (MATRIX_ROW_SHIFTER << col_index);
+    }
+
+    return state;
+}
+
+static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+    matrix_row_t last_row_value = current_matrix[current_row];
+
+    select_row(current_row);
+    select_secondary_row(current_row);
+
+    current_matrix[current_row] = read_cols() | (read_secondary_cols() << 6);
+
+    unselect_row(current_row);
+
+    return (last_row_value != current_matrix[current_row]);
+}
+
+void matrix_init_custom(void) { init_pins(); }
+
+bool matrix_scan_custom(matrix_row_t current_matrix[]) {
+    bool changed = false;
+
+    for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
+        changed |= read_cols_on_row(current_matrix, current_row);
+    }
+
+    return changed;
+}