keyboards/ryanskidmore: add rskeys100 keyboard (#15506)

* keyboards/ryanskidmore/rskeys100: add rskeys100 draft firmware

* keyboards/ryanskidmore/rskeys100: fix firmware

* ryanskidmore/rskeys100: fix remaining bugs

* keyboards/ryanskidmore/rskeys100: finishing touches on firmware

* keyboards/ryanskidmore/rskeys100: migrate from full replacement matrix scanning to lite, move rgb matrix enable call to keymap

* keyboards/ryanskidmore/rskeys100: remove undefines, clarify comments

* ryanskidmore/rskeys100: remove unused imports

* keyboards/ryanskidmore/rskeys100: pr feedback

1 files changed, 110 insertions, 0 deletions

diff --git a/keyboards/ryanskidmore/rskeys100/matrix.c b/keyboards/ryanskidmore/rskeys100/matrix.c
new file mode 100644
index 0000000000..faefb29c84
--- /dev/null
+++ b/keyboards/ryanskidmore/rskeys100/matrix.c
@@ -0,0 +1,110 @@
+/*
+Copyright 2014 Ralf Schmitt <ralf@bunkertor.net>
+Modified by Ryan Skidmore <rskeys@ryanskidmore.co.uk> (@ryanskidmore)
+to support the rskeys100.
+
+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 <stdbool.h>
+#include "matrix.h"
+#include <util/delay.h>
+#include "quantum.h"
+
+static const uint32_t col_values[24] = SHR_COLS;
+
+static uint8_t read_rows(void);
+static void    select_col(uint8_t col);
+
+static void    shift_pulse(void);
+static void    shift_out_single(uint8_t value);
+static void    shift_out(uint32_t value);
+
+void matrix_init_custom(void) {
+  setPinInput(ROW_A);
+  setPinInput(ROW_B);
+  setPinInput(ROW_C);
+  setPinInput(ROW_D);
+  setPinInput(ROW_E);
+  setPinInput(ROW_F);
+
+  setPinOutput(SHR_DATA);
+  setPinOutput(SHR_LATCH);
+  setPinOutput(SHR_CLOCK);
+}
+
+bool matrix_scan_custom(matrix_row_t current_matrix[]) {
+    bool changed = false;
+
+    for (uint8_t col = 0; col < MATRIX_COLS; col++) {
+        select_col(col);
+        _delay_us(1);
+        uint8_t rows = read_rows();
+        for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
+            bool prev_bit = ((uint32_t)(current_matrix[row]) & (matrix_row_t)(1UL << col)) ? 1 : 0;
+            bool curr_bit = ((uint32_t)rows & (uint32_t)(1UL << row)) ? 1 : 0;
+            if (prev_bit != curr_bit) {
+                current_matrix[row] = (uint32_t)(current_matrix[row]) ^ (uint32_t)(1UL << col);
+                changed = true;
+            }
+        }
+    }
+
+    return changed;
+}
+
+static uint8_t read_rows(void) {
+  return (readPin(ROW_F) << 5)
+         | (readPin(ROW_E) << 4)
+         | (readPin(ROW_D) << 3)
+         | (readPin(ROW_C) << 2)
+         | (readPin(ROW_B) << 1)
+         | (readPin(ROW_A) );
+}
+
+static void select_col(uint8_t col) {
+    shift_out(col_values[col]);
+}
+
+static void shift_out(uint32_t value) {
+  writePinLow(SHR_LATCH);
+  uint8_t first_byte  = (value >> 16) & 0xFF;
+  uint8_t second_byte  = (value >> 8) & 0xFF;
+  uint8_t third_byte = (uint8_t)(value & 0xFF);
+
+  shift_out_single(first_byte);
+  shift_out_single(second_byte);
+  shift_out_single(third_byte);
+  writePinHigh(SHR_LATCH);
+  /* We delay here to prevent multiple consecutive keys being triggered with a single switch press */
+  _delay_us(10);
+}
+
+static void shift_out_single(uint8_t value) {
+    for (uint8_t i = 0; i < 8; i++) {
+        if (value & 0b10000000) {
+            writePinHigh(SHR_DATA);
+        } else {
+            writePinLow(SHR_DATA);
+        }
+
+        shift_pulse();
+        value = value << 1;
+    }
+}
+
+static inline void shift_pulse(void) {
+    writePinHigh(SHR_CLOCK);
+    writePinLow(SHR_CLOCK);
+}
\ No newline at end of file