1 files changed, 131 insertions, 0 deletions
diff --git a/keyboards/handwired/dqz11n1g/matrix.c b/keyboards/handwired/dqz11n1g/matrix.c
new file mode 100644
index 0000000000..f9f3f2b68f
--- /dev/null
+++ b/keyboards/handwired/dqz11n1g/matrix.c
@@ -0,0 +1,131 @@
+/*
+  Copyright (c) 2022 David Kuehling <dvdkhlng TA posteo TOD de>
+
+  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 <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <avr/io.h>
+
+#include "spi_master.h"
+#include "quantum.h"
+#include "matrix.h"
+
+static pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
+
+static void unselect_rows(void);
+
+void matrix_init_custom(void) {
+    /* initialize row pins */
+    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+        setPinOutput(row_pins[row]);
+    }
+    unselect_rows();
+
+    /* columns read via shift-register on SPI lines */
+
+    /* Enable SPI, Master, set clock rate fck/2.  First bit already at Qh
+     * output before clock edge (CPHA=0).  SN74HC165 shift register shifts
+     * on low-to-high transition (CPOL=1).  Receive the LSB first (DORD=1).
+     */
+    bool lsbFirst = true;
+    uint8_t mode = 2;  /* CPOL=1, CPHA=0 */
+    uint16_t divisor = 16;
+
+    /* According to Atmega32U4 datasheet, PB0 *must* be set to output,
+     * otherwise it will interfere with SPI master operation.  On pro-micro
+     * it's connected to a yellew LED. */
+    pin_t slavePin = PB0;
+    spi_init();
+    spi_start(slavePin, lsbFirst, mode, divisor);
+
+    /* Initialize pin controlling the shift register's SH/~LD pin */
+    setPinOutput(ROW_SHIFT_PIN);
+}
+
+static void select_row(uint8_t row) {
+    pin_t pin = row_pins[row];
+    if (pin != NO_PIN) {
+        writePinHigh(pin);
+    }
+}
+
+static void unselect_row(uint8_t row) {
+    pin_t pin = row_pins[row];
+    if (pin != NO_PIN) {
+        writePinLow(pin);
+    }
+}
+
+static void unselect_rows(void) {
+    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+        unselect_row(row);
+    }
+}
+
+bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
+    /* Start with a clear matrix row */
+    matrix_row_t current_row_value = 0;
+
+    /* Set shift register SH/~LD pin to "load" mode */
+    writePinLow(ROW_SHIFT_PIN);
+    select_row(current_row);
+    matrix_output_select_delay();
+
+    /* Set shift register SH/~LD pin to "shift" mode */
+    writePinHigh(ROW_SHIFT_PIN);
+
+    /* For each octet of columns... */
+    for (uint8_t col_index = 0; col_index < MATRIX_COLS; col_index += 8) {
+        spi_status_t read_result = spi_read();
+        if (read_result >= 0) {
+            /* only if SPI read successful: populate the matrix row with the
+               state of the 8 consecutive column bits */
+            current_row_value |= ((matrix_row_t)read_result << col_index);
+        }
+    }
+
+    /* Unselect row & wait for all columns signals to go high. */
+    unselect_row(current_row);
+    matrix_output_unselect_delay(current_row, current_row_value != 0); 
+
+    /* Update row in matrix. */
+    if (current_row_value != current_matrix[current_row]) {
+        current_matrix[current_row] = current_row_value;
+        return true;
+    }
+
+    return false;
+}
+
+bool matrix_scan_custom(matrix_row_t curr_matrix[]) {
+    bool changed = false;
+
+    /* set row, read cols */
+    for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
+        changed |= matrix_read_cols_on_row(curr_matrix, current_row);
+    }
+
+    return changed;
+}
+
+/*
+ * Local Variables:
+ * c-basic-offset:4
+ * fill-column: 76
+ * End:
+ */