Update to xealousbrown. (#8215)

* Update to xealousbrown.

5-13ms Latency decrease, 4x scan rate improvement.
(CUSTOM_MATRIX = lite) is a really great feature!

* Updated Readme.md, added an extra speedhack.

* More optimizations

* Update keyboards/handwired/xealousbrown/rules.mk

* Update keyboards/handwired/xealousbrown/rules.mk

1 files changed, 112 insertions, 0 deletions

diff --git a/keyboards/handwired/xealousbrown/matrix.c b/keyboards/handwired/xealousbrown/matrix.c
new file mode 100644
index 000000000..cce0d06eb
--- /dev/null
+++ b/keyboards/handwired/xealousbrown/matrix.c
@@ -0,0 +1,112 @@
+/*
+Copyright 2019 Alex Ong
+
+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 "wait.h"
+#include "util.h"
+#include "matrix.h"
+#include "debounce.h"
+#include "quantum.h"
+
+/* matrix state(1:on, 0:off) */
+extern matrix_row_t raw_matrix[MATRIX_ROWS];  // raw values
+extern matrix_row_t matrix[MATRIX_ROWS];      // debounced values
+
+// matrix code
+// super fast read_cols code.
+static matrix_row_t read_cols(void) {
+    return (PINC & (1 << 6) ? 0 : (1UL << 0)) |
+           (PIND & (1 << 7) ? 0 : (1UL << 1)) |
+           (PINE & (1 << 6) ? 0 : (1UL << 2)) |
+           (PINB & (1 << 4) ? 0 : (1UL << 3)) |
+           (PINB & (1 << 5) ? 0 : (1UL << 4)) |
+           (PINB & (1 << 6) ? 0 : (1UL << 5)) |
+           (PINB & (1 << 2) ? 0 : (1UL << 6)) |
+           (PINB & (1 << 3) ? 0 : (1UL << 7)) |
+           (PINB & (1 << 1) ? 0 : (1UL << 8)) |
+           (PINF & (1 << 7) ? 0 : (1UL << 9)) |
+           (PINF & (1 << 6) ? 0 : (1UL << 10)) |
+           (PINF & (1 << 5) ? 0 : (1UL << 11)) |
+           (PINF & (1 << 4) ? 0 : (1UL << 12));
+}
+
+static void unselect_rows(void) {
+    DDRD &= ~0b00011111;
+    PORTD &= ~0b00011111;
+}
+
+static void select_row(uint8_t row) {
+    switch (row) {
+        case 0:
+            DDRD |= (1 << 3);
+            PORTD &= ~(1 << 3);
+            break;
+        case 1:
+            DDRD |= (1 << 2);
+            PORTD &= ~(1 << 2);
+            break;
+        case 2:
+            DDRD |= (1 << 1);
+            PORTD &= ~(1 << 1);
+            break;
+        case 3:
+            DDRD |= (1 << 0);
+            PORTD &= ~(1 << 0);
+            break;
+        case 4:
+            DDRD |= (1 << 4);
+            PORTD &= ~(1 << 4);
+            break;
+    }
+}
+
+static void init_pins(void) {
+    DDRC &= ~(1 << 6);
+    PORTC |= (1 << 6);
+    DDRD &= ~(1 << 7);
+    PORTD |= (1 << 7);
+    DDRE &= ~(1 << 6);
+    PORTE |= (1 << 6);
+    DDRB &= ~(1 << 4 | 1 << 5 | 1 << 6 | 1 << 2 | 1 << 3 | 1 << 1);
+    PORTB |= (1 << 4 | 1 << 5 | 1 << 6 | 1 << 2 | 1 << 3 | 1 << 1);
+    DDRF &= ~(1 << 7 | 1 << 6 | 1 << 5 | 1 << 4);
+    PORTF |= (1 << 7 | 1 << 6 | 1 << 5 | 1 << 4);
+}
+
+// Only need to init the pins. Debounce / raw matrix are initialized already for us.
+void matrix_init_custom(void) {
+    // initialize key pins
+    init_pins();
+}
+
+// Only need to scan the result into current_matrix, and return changed.
+uint8_t matrix_scan_custom(matrix_row_t current_matrix[]) {
+    bool changed = false;
+
+    // Set row, read cols
+    for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
+        select_row(current_row);
+        asm volatile("nop");
+        asm volatile("nop");
+        matrix_row_t cols = read_cols();
+        changed |= (current_matrix[current_row] != cols);
+        current_matrix[current_row] = cols;
+        unselect_rows();
+    }
+
+    return changed;
+}