add encoder docs

docs/_summary.md

@@ -34,6 +34,7 @@
   * [Bootmagic](feature_bootmagic.md)
   * [Command](feature_command.md)
   * [Dynamic Macros](feature_dynamic_macros.md)
+  * [Encoders](feature_encoders.md)
   * [Grave Escape](feature_grave_esc.md)
   * [Key Lock](feature_key_lock.md)
   * [Layouts](feature_layouts.md)

docs/feature_encoders.md

@@ -0,0 +1,41 @@
+# Encoders
+
+Basic encoders are supported by adding this to your `rules.mk`:
+
+    ENCODER_ENABLE = yes
+
+and this to your `config.h`:
+
+    #define NUMBER_OF_ENCODERS 1
+    #define ENCODERS_PAD_A { B12 }
+    #define ENCODERS_PAD_B { B13 }
+
+Each PAD_A/B variable defines an array so multiple encoders can be defined, e.g.:
+
+    #define ENCODERS_PAD_A { encoder1a, encoder2a }
+    #define ENCODERS_PAD_B { encoder1a, encoder2b }
+
+If your encoder's clockwise directions are incorrect, you can swap the A & B pad definitions.
+
+Additionally, the resolution can be specified in the same file (the default & suggested is 4):
+
+    #define ENCODER_RESOLUTION 4
+
+## Callbacks
+
+The callback functions can be inserted into your `<keyboard>.c`:
+
+    void encoder_update_kb(uint8_t index, bool clockwise) {
+        encoder_update_user(index, clockwise);
+    }
+
+or `keymap.c`:
+
+    void encoder_update_user(uint8_t index, bool clockwise) {
+        
+    }
+
+
+## Hardware
+
+The A an B lines of the encoders should be wired directly to the MCU, and the C/common lines should be wired to ground.

keyboards/planck/keymaps/default/keymap.c

@@ -259,7 +259,7 @@ uint16_t muse_counter = 0;
 uint8_t muse_offset = 70;
 uint16_t muse_tempo = 50;
 
-void encoder_update(bool clockwise) {
+void encoder_update_user(int8_t index, bool clockwise) {
   if (muse_mode) {
     if (IS_LAYER_ON(_RAISE)) {
       if (clockwise) {

quantum/encoder.c

@@ -35,11 +35,11 @@ static uint8_t encoder_state[NUMBER_OF_ENCODERS] = {0};
 static int8_t encoder_value[NUMBER_OF_ENCODERS] = {0};
 
 __attribute__ ((weak))
-void encoder_update_user(bool clockwise) { }
+void encoder_update_user(int8_t index, bool clockwise) { }
 
 __attribute__ ((weak))
-void encoder_update_kb(bool clockwise) {
+void encoder_update_kb(int8_t index, bool clockwise) {
-  encoder_update_user(clockwise);
+  encoder_update_user(index, clockwise);
 }
 
 void encoder_init(void) {
@@ -57,10 +57,10 @@ void encoder_read(void) {
     encoder_state[i] |= (readPad(encoders_pad_a[i]) << 0) | (readPad(encoders_pad_b[i]) << 1);
     encoder_value[i] += encoder_LUT[encoder_state[i] & 0xF];
     if (encoder_value[i] >= ENCODER_RESOLUTION) {
-        encoder_update_kb(COUNTRECLOCKWISE);
+        encoder_update_kb(i, COUNTRECLOCKWISE);
     }
     if (encoder_value[i] <= -ENCODER_RESOLUTION) { // direction is arbitrary here, but this clockwise
-        encoder_update_kb(CLOCKWISE);
+        encoder_update_kb(i, CLOCKWISE);
     }
     encoder_value[i] %= ENCODER_RESOLUTION;
   }