1 files changed, 70 insertions, 0 deletions
diff --git a/quantum/encoder.c b/quantum/encoder.c
new file mode 100644
index 000000000..6629a098b
--- /dev/null
+++ b/quantum/encoder.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 Jack Humbert <jack.humb@gmail.com>
+ *
+ * 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 "encoder.h"
+
+#ifndef ENCODER_RESOLUTION
+  #define ENCODER_RESOLUTION 4
+#endif
+
+#ifndef NUMBER_OF_ENCODERS
+  #error "Number of encoders not defined by NUMBER_OF_ENCODERS"
+#endif
+
+#if !defined(ENCODERS_PAD_A) || !defined(ENCODERS_PAD_B)
+  #error "No encoder pads defined by ENCODERS_PAD_A and ENCODERS_PAD_B"
+#endif
+
+static pin_t encoders_pad_a[NUMBER_OF_ENCODERS] = ENCODERS_PAD_A;
+static pin_t encoders_pad_b[NUMBER_OF_ENCODERS] = ENCODERS_PAD_B;
+
+static int8_t encoder_LUT[] = { 0, -1, 1, 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 1, -1, 0 };
+
+static uint8_t encoder_state[NUMBER_OF_ENCODERS] = {0};
+static int8_t encoder_value[NUMBER_OF_ENCODERS] = {0};
+
+__attribute__ ((weak))
+void encoder_update_user(int8_t index, bool clockwise) { }
+
+__attribute__ ((weak))
+void encoder_update_kb(int8_t index, bool clockwise) {
+  encoder_update_user(index, clockwise);
+}
+
+void encoder_init(void) {
+  for (int i = 0; i < NUMBER_OF_ENCODERS; i++) {
+    setPinInputHigh(encoders_pad_a[i]);
+    setPinInputHigh(encoders_pad_b[i]);
+
+    encoder_state[i] = (readPin(encoders_pad_a[i]) << 0) | (readPin(encoders_pad_b[i]) << 1);
+  }
+}
+
+void encoder_read(void) {
+  for (int i = 0; i < NUMBER_OF_ENCODERS; i++) {
+    encoder_state[i] <<= 2;
+    encoder_state[i] |= (readPin(encoders_pad_a[i]) << 0) | (readPin(encoders_pad_b[i]) << 1);
+    encoder_value[i] += encoder_LUT[encoder_state[i] & 0xF];
+    if (encoder_value[i] >= ENCODER_RESOLUTION) {
+        encoder_update_kb(i, COUNTRECLOCKWISE);
+    }
+    if (encoder_value[i] <= -ENCODER_RESOLUTION) { // direction is arbitrary here, but this clockwise
+        encoder_update_kb(i, CLOCKWISE);
+    }
+    encoder_value[i] %= ENCODER_RESOLUTION;
+  }
+}