Rework encoders to enable asymmetric split keyboards (#12090)

Co-authored-by: Balz Guenat <balz.guenat@siemens.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

11 files changed, 559 insertions, 57 deletions

diff --git a/quantum/encoder.c b/quantum/encoder.c
index 8fb87281c2..7d4e978981 100644
--- a/quantum/encoder.c
+++ b/quantum/encoder.c
@@ -16,8 +16,17 @@
  */
 
 #include "encoder.h"
-#ifdef SPLIT_KEYBOARD
-#    include "split_util.h"
+
+// this is for unit testing
+#if defined(ENCODER_MOCK_SINGLE)
+#    include "encoder/tests/mock.h"
+#elif defined(ENCODER_MOCK_SPLIT)
+#    include "encoder/tests/mock_split.h"
+#else
+#    include <gpio.h>
+#    ifdef SPLIT_KEYBOARD
+#        include "split_util.h"
+#    endif
 #endif
 
 // for memcpy
@@ -27,17 +36,41 @@
 #    define ENCODER_RESOLUTION 4
 #endif
 
-#if !defined(ENCODERS_PAD_A) || !defined(ENCODERS_PAD_B)
-#    error "No encoder pads defined by ENCODERS_PAD_A and ENCODERS_PAD_B"
+#if (!defined(ENCODERS_PAD_A) || !defined(ENCODERS_PAD_B)) && (!defined(ENCODERS_PAD_A) || !defined(ENCODERS_PAD_B))
+#    error "No encoder pads defined by ENCODERS_PAD_A and ENCODERS_PAD_B or ENCODERS_PAD_A_RIGHT and ENCODERS_PAD_B_RIGHT"
 #endif
 
-#define NUMBER_OF_ENCODERS (sizeof(encoders_pad_a) / sizeof(pin_t))
+// on split keyboards, these are the pads and resolutions for the left half
 static pin_t encoders_pad_a[] = ENCODERS_PAD_A;
 static pin_t encoders_pad_b[] = ENCODERS_PAD_B;
 #ifdef ENCODER_RESOLUTIONS
 static uint8_t encoder_resolutions[] = ENCODER_RESOLUTIONS;
 #endif
 
+#ifndef SPLIT_KEYBOARD
+#    define NUMBER_OF_ENCODERS (sizeof(encoders_pad_a) / sizeof(pin_t))
+#else
+// if no pads for right half are defined, we assume the keyboard is symmetric (i.e. same pads)
+#    ifndef ENCODERS_PAD_A_RIGHT
+#        define ENCODERS_PAD_A_RIGHT ENCODERS_PAD_A
+#    endif
+#    ifndef ENCODERS_PAD_B_RIGHT
+#        define ENCODERS_PAD_B_RIGHT ENCODERS_PAD_B
+#    endif
+#    if defined(ENCODER_RESOLUTIONS) && !defined(ENCODER_RESOLUTIONS_RIGHT)
+#        define ENCODER_RESOLUTIONS_RIGHT ENCODER_RESOLUTIONS
+#    endif
+
+#    define NUMBER_OF_ENCODERS ((sizeof(encoders_pad_a) + sizeof(encoders_pad_a_right)) / sizeof(pin_t))
+#    define NUMBER_OF_ENCODERS_LEFT (sizeof(encoders_pad_a) / sizeof(pin_t))
+#    define NUMBER_OF_ENCODERS_RIGHT (sizeof(encoders_pad_a_right) / sizeof(pin_t))
+static pin_t   encoders_pad_a_right[]      = ENCODERS_PAD_A_RIGHT;
+static pin_t   encoders_pad_b_right[]      = ENCODERS_PAD_B_RIGHT;
+#    ifdef ENCODER_RESOLUTIONS_RIGHT
+static uint8_t encoder_resolutions_right[] = ENCODER_RESOLUTIONS_RIGHT;
+#    endif
+#endif
+
 #ifndef ENCODER_DIRECTION_FLIP
 #    define ENCODER_CLOCKWISE true
 #    define ENCODER_COUNTER_CLOCKWISE false
@@ -50,78 +83,81 @@ static int8_t encoder_LUT[] = {0, -1, 1, 0, 1, 0, 0, -1, -1, 0, 0, 1, 0, 1, -1,
 static uint8_t encoder_state[NUMBER_OF_ENCODERS]  = {0};
 static int8_t  encoder_pulses[NUMBER_OF_ENCODERS] = {0};
 
-#ifdef SPLIT_KEYBOARD
-// right half encoders come over as second set of encoders
-static uint8_t encoder_value[NUMBER_OF_ENCODERS * 2] = {0};
-// row offsets for each hand
-static uint8_t thisHand, thatHand;
-#else
 static uint8_t encoder_value[NUMBER_OF_ENCODERS] = {0};
-#endif
 
 __attribute__((weak)) bool encoder_update_user(uint8_t index, bool clockwise) { return true; }
 
 __attribute__((weak)) bool encoder_update_kb(uint8_t index, bool clockwise) { return encoder_update_user(index, clockwise); }
 
+// number of encoders connected to this controller
+static uint8_t numEncodersHere;
+// index of the first encoder connected to this controller (only for right halves, this will be nonzero)
+static uint8_t firstEncoderHere;
+#ifdef SPLIT_KEYBOARD
+// index of the first encoder connected to the other half
+static uint8_t firstEncoderThere;
+#endif
+// the pads for this controller
+static pin_t* pad_a;
+static pin_t* pad_b;
+
 void encoder_init(void) {
-#if defined(SPLIT_KEYBOARD) && defined(ENCODERS_PAD_A_RIGHT) && defined(ENCODERS_PAD_B_RIGHT)
-    if (!isLeftHand) {
-        const pin_t encoders_pad_a_right[] = ENCODERS_PAD_A_RIGHT;
-        const pin_t encoders_pad_b_right[] = ENCODERS_PAD_B_RIGHT;
-#    if defined(ENCODER_RESOLUTIONS_RIGHT)
-        const uint8_t encoder_resolutions_right[] = ENCODER_RESOLUTIONS_RIGHT;
-#    endif
-        for (uint8_t i = 0; i < NUMBER_OF_ENCODERS; i++) {
-            encoders_pad_a[i] = encoders_pad_a_right[i];
-            encoders_pad_b[i] = encoders_pad_b_right[i];
-#    if defined(ENCODER_RESOLUTIONS_RIGHT)
-            encoder_resolutions[i] = encoder_resolutions_right[i];
-#    endif
-        }
+#ifndef SPLIT_KEYBOARD
+    numEncodersHere  = NUMBER_OF_ENCODERS;
+    pad_a            = encoders_pad_a;
+    pad_b            = encoders_pad_b;
+    firstEncoderHere = 0;
+#else
+    if (isLeftHand) {
+        numEncodersHere   = NUMBER_OF_ENCODERS_LEFT;
+        pad_a             = encoders_pad_a;
+        pad_b             = encoders_pad_b;
+        firstEncoderHere  = 0;
+        firstEncoderThere = NUMBER_OF_ENCODERS_LEFT;
+    } else {
+        numEncodersHere   = NUMBER_OF_ENCODERS_RIGHT;
+        pad_a             = encoders_pad_a_right;
+        pad_b             = encoders_pad_b_right;
+        firstEncoderHere  = NUMBER_OF_ENCODERS_LEFT;
+        firstEncoderThere = 0;
     }
 #endif
 
-    for (int i = 0; i < NUMBER_OF_ENCODERS; i++) {
-        setPinInputHigh(encoders_pad_a[i]);
-        setPinInputHigh(encoders_pad_b[i]);
+    for (int i = 0; i < numEncodersHere; i++) {
+        setPinInputHigh(pad_a[i]);
+        setPinInputHigh(pad_b[i]);
 
-        encoder_state[i] = (readPin(encoders_pad_a[i]) << 0) | (readPin(encoders_pad_b[i]) << 1);
+        encoder_state[firstEncoderHere + i] = (readPin(pad_a[i]) << 0) | (readPin(pad_b[i]) << 1);
     }
-
-#ifdef SPLIT_KEYBOARD
-    thisHand = isLeftHand ? 0 : NUMBER_OF_ENCODERS;
-    thatHand = NUMBER_OF_ENCODERS - thisHand;
-#endif
 }
 
-static bool encoder_update(uint8_t index, uint8_t state) {
-    bool    changed = false;
-    uint8_t i       = index;
+static bool encoder_update(int8_t index, uint8_t state) {
+    bool changed = false;
 
 #ifdef ENCODER_RESOLUTIONS
-    uint8_t resolution = encoder_resolutions[i];
+#    ifndef SPLIT_KEYBOARD
+    int8_t resolution = encoder_resolutions[index];
+#    else
+    int8_t resolution = isLeftHand ? encoder_resolutions[index] : encoder_resolutions_right[index - NUMBER_OF_ENCODERS_LEFT];
+#    endif
 #else
     uint8_t resolution = ENCODER_RESOLUTION;
 #endif
-
-#ifdef SPLIT_KEYBOARD
-    index += thisHand;
-#endif
-    encoder_pulses[i] += encoder_LUT[state & 0xF];
-    if (encoder_pulses[i] >= resolution) {
+    encoder_pulses[index] += encoder_LUT[state & 0xF];
+    if (encoder_pulses[index] >= resolution) {
         encoder_value[index]++;
         changed = true;
         encoder_update_kb(index, ENCODER_COUNTER_CLOCKWISE);
     }
-    if (encoder_pulses[i] <= -resolution) {  // direction is arbitrary here, but this clockwise
+    if (encoder_pulses[index] <= -resolution) {  // direction is arbitrary here, but this clockwise
         encoder_value[index]--;
         changed = true;
         encoder_update_kb(index, ENCODER_CLOCKWISE);
     }
-    encoder_pulses[i] %= resolution;
+    encoder_pulses[index] %= resolution;
 #ifdef ENCODER_DEFAULT_POS
     if ((state & 0x3) == ENCODER_DEFAULT_POS) {
-        encoder_pulses[i] = 0;
+        encoder_pulses[index] = 0;
     }
 #endif
     return changed;
@@ -129,10 +165,10 @@ static bool encoder_update(uint8_t index, uint8_t state) {
 
 bool encoder_read(void) {
     bool changed = false;
-    for (uint8_t 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);
-        changed |= encoder_update(i, encoder_state[i]);
+    for (uint8_t i = 0; i < numEncodersHere; i++) {
+        encoder_state[firstEncoderHere + i] <<= 2;
+        encoder_state[firstEncoderHere + i] |= (readPin(pad_a[i]) << 0) | (readPin(pad_b[i]) << 1);
+        changed |= encoder_update(firstEncoderHere + i, encoder_state[firstEncoderHere + i]);
     }
     return changed;
 }
@@ -140,12 +176,12 @@ bool encoder_read(void) {
 #ifdef SPLIT_KEYBOARD
 void last_encoder_activity_trigger(void);
 
-void encoder_state_raw(uint8_t* slave_state) { memcpy(slave_state, &encoder_value[thisHand], sizeof(uint8_t) * NUMBER_OF_ENCODERS); }
+void encoder_state_raw(uint8_t* slave_state) { memcpy(slave_state, &encoder_value[firstEncoderHere], sizeof(uint8_t) * numEncodersHere); }
 
 void encoder_update_raw(uint8_t* slave_state) {
     bool changed = false;
-    for (uint8_t i = 0; i < NUMBER_OF_ENCODERS; i++) {
-        uint8_t index = i + thatHand;
+    for (uint8_t i = 0; i < NUMBER_OF_ENCODERS - numEncodersHere; i++) {
+        uint8_t index = firstEncoderThere + i;
         int8_t  delta = slave_state[i] - encoder_value[index];
         while (delta > 0) {
             delta--;
diff --git a/quantum/encoder.h b/quantum/encoder.h
index 25dc77721d..67f71ec0f0 100644
--- a/quantum/encoder.h
+++ b/quantum/encoder.h
@@ -17,7 +17,8 @@
 
 #pragma once
 
-#include "quantum.h"
+#include <stdbool.h>
+#include <stdint.h>
 
 void encoder_init(void);
 bool encoder_read(void);
diff --git a/quantum/encoder/tests/encoder_tests.cpp b/quantum/encoder/tests/encoder_tests.cpp
new file mode 100644
index 0000000000..1888fdab8d
--- /dev/null
+++ b/quantum/encoder/tests/encoder_tests.cpp
@@ -0,0 +1,144 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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 "gtest/gtest.h"
+#include "gmock/gmock.h"
+#include <vector>
+#include <algorithm>
+#include <stdio.h>
+
+extern "C" {
+#include "encoder.h"
+#include "encoder/tests/mock.h"
+}
+
+struct update {
+    int8_t index;
+    bool   clockwise;
+};
+
+uint8_t uidx = 0;
+update  updates[32];
+
+bool encoder_update_kb(uint8_t index, bool clockwise) {
+    updates[uidx % 32] = {index, clockwise};
+    uidx++;
+    return true;
+}
+
+bool setAndRead(pin_t pin, bool val) {
+    setPin(pin, val);
+    return encoder_read();
+}
+
+class EncoderTest : public ::testing::Test {};
+
+TEST_F(EncoderTest, TestInit) {
+    uidx = 0;
+    encoder_init();
+    EXPECT_EQ(pinIsInputHigh[0], true);
+    EXPECT_EQ(pinIsInputHigh[1], true);
+    EXPECT_EQ(uidx, 0);
+}
+
+TEST_F(EncoderTest, TestOneClockwise) {
+    uidx = 0;
+    encoder_init();
+    // send 4 pulses. with resolution 4, that's one step and we should get 1 update.
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    setAndRead(1, true);
+
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, true);
+}
+
+TEST_F(EncoderTest, TestOneCounterClockwise) {
+    uidx = 0;
+    encoder_init();
+    setAndRead(1, false);
+    setAndRead(0, false);
+    setAndRead(1, true);
+    setAndRead(0, true);
+
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, false);
+}
+
+TEST_F(EncoderTest, TestTwoClockwiseOneCC) {
+    uidx = 0;
+    encoder_init();
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    setAndRead(1, true);
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    setAndRead(1, true);
+    setAndRead(1, false);
+    setAndRead(0, false);
+    setAndRead(1, true);
+    setAndRead(0, true);
+
+    EXPECT_EQ(uidx, 3);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, true);
+    EXPECT_EQ(updates[1].index, 0);
+    EXPECT_EQ(updates[1].clockwise, true);
+    EXPECT_EQ(updates[2].index, 0);
+    EXPECT_EQ(updates[2].clockwise, false);
+}
+
+TEST_F(EncoderTest, TestNoEarly) {
+    uidx = 0;
+    encoder_init();
+    // send 3 pulses. with resolution 4, that's not enough for a step.
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    EXPECT_EQ(uidx, 0);
+    // now send last pulse
+    setAndRead(1, true);
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, true);
+}
+
+TEST_F(EncoderTest, TestHalfway) {
+    uidx = 0;
+    encoder_init();
+    // go halfway
+    setAndRead(0, false);
+    setAndRead(1, false);
+    EXPECT_EQ(uidx, 0);
+    // back off
+    setAndRead(1, true);
+    setAndRead(0, true);
+    EXPECT_EQ(uidx, 0);
+    // go all the way
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    setAndRead(1, true);
+    // should result in 1 update
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, true);
+}
diff --git a/quantum/encoder/tests/encoder_tests_split.cpp b/quantum/encoder/tests/encoder_tests_split.cpp
new file mode 100644
index 0000000000..25e52c83f9
--- /dev/null
+++ b/quantum/encoder/tests/encoder_tests_split.cpp
@@ -0,0 +1,143 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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 "gtest/gtest.h"
+#include "gmock/gmock.h"
+#include <vector>
+#include <algorithm>
+#include <stdio.h>
+
+extern "C" {
+#include "encoder.h"
+#include "encoder/tests/mock_split.h"
+}
+
+struct update {
+    int8_t index;
+    bool   clockwise;
+};
+
+uint8_t uidx = 0;
+update  updates[32];
+
+bool isLeftHand;
+
+bool encoder_update_kb(uint8_t index, bool clockwise) {
+    if (!isLeftHand) {
+        // this method has no effect on slave half
+        printf("ignoring update on right hand (%d,%s)\n", index, clockwise ? "CW" : "CC");
+        return true;
+    }
+    updates[uidx % 32] = {index, clockwise};
+    uidx++;
+    return true;
+}
+
+bool setAndRead(pin_t pin, bool val) {
+    setPin(pin, val);
+    return encoder_read();
+}
+
+class EncoderTest : public ::testing::Test {
+   protected:
+    void SetUp() override {
+        uidx = 0;
+        for (int i = 0; i < 32; i++) {
+            pinIsInputHigh[i] = 0;
+            pins[i]           = 0;
+        }
+    }
+};
+
+TEST_F(EncoderTest, TestInitLeft) {
+    isLeftHand = true;
+    encoder_init();
+    EXPECT_EQ(pinIsInputHigh[0], true);
+    EXPECT_EQ(pinIsInputHigh[1], true);
+    EXPECT_EQ(pinIsInputHigh[2], false);
+    EXPECT_EQ(pinIsInputHigh[3], false);
+    EXPECT_EQ(uidx, 0);
+}
+
+TEST_F(EncoderTest, TestInitRight) {
+    isLeftHand = false;
+    encoder_init();
+    EXPECT_EQ(pinIsInputHigh[0], false);
+    EXPECT_EQ(pinIsInputHigh[1], false);
+    EXPECT_EQ(pinIsInputHigh[2], true);
+    EXPECT_EQ(pinIsInputHigh[3], true);
+    EXPECT_EQ(uidx, 0);
+}
+
+TEST_F(EncoderTest, TestOneClockwiseLeft) {
+    isLeftHand = true;
+    encoder_init();
+    // send 4 pulses. with resolution 4, that's one step and we should get 1 update.
+    setAndRead(0, false);
+    setAndRead(1, false);
+    setAndRead(0, true);
+    setAndRead(1, true);
+
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 0);
+    EXPECT_EQ(updates[0].clockwise, true);
+}
+
+TEST_F(EncoderTest, TestOneClockwiseRightSent) {
+    isLeftHand = false;
+    encoder_init();
+    // send 4 pulses. with resolution 4, that's one step and we should get 1 update.
+    setAndRead(2, false);
+    setAndRead(3, false);
+    setAndRead(2, true);
+    setAndRead(3, true);
+
+    uint8_t slave_state[2] = {0};
+    encoder_state_raw(slave_state);
+
+    EXPECT_EQ((int8_t)slave_state[0], -1);
+}
+
+/* this test will not work after the previous test.
+ * this is due to encoder_value[1] already being set to -1 when simulating the right half.
+ * When we now receive this update acting as the left half, there is no change.
+ * This is hard to mock, as the static values inside encoder.c normally exist twice, once on each half,
+ * but here, they only exist once.
+ */
+
+// TEST_F(EncoderTest, TestOneClockwiseRightReceived) {
+//     isLeftHand = true;
+//     encoder_init();
+
+//     uint8_t slave_state[2] = {255, 0};
+//     encoder_update_raw(slave_state);
+
+//     EXPECT_EQ(uidx, 1);
+//     EXPECT_EQ(updates[0].index, 1);
+//     EXPECT_EQ(updates[0].clockwise, true);
+// }
+
+TEST_F(EncoderTest, TestOneCounterClockwiseRightReceived) {
+    isLeftHand = true;
+    encoder_init();
+
+    uint8_t slave_state[2] = {0, 0};
+    encoder_update_raw(slave_state);
+
+    EXPECT_EQ(uidx, 1);
+    EXPECT_EQ(updates[0].index, 1);
+    EXPECT_EQ(updates[0].clockwise, false);
+}
diff --git a/quantum/encoder/tests/mock.c b/quantum/encoder/tests/mock.c
new file mode 100644
index 0000000000..d0506a938f
--- /dev/null
+++ b/quantum/encoder/tests/mock.c
@@ -0,0 +1,34 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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 "mock.h"
+
+bool pins[32]           = {0};
+bool pinIsInputHigh[32] = {0};
+
+uint8_t mockSetPinInputHigh(pin_t pin) {
+    // dprintf("Setting pin %d input high.", pin);
+    pins[pin]           = true;
+    pinIsInputHigh[pin] = true;
+    return 0;
+}
+
+bool mockReadPin(pin_t pin) { return pins[pin]; }
+
+bool setPin(pin_t pin, bool val) {
+    pins[pin] = val;
+    return val;
+}
diff --git a/quantum/encoder/tests/mock.h b/quantum/encoder/tests/mock.h
new file mode 100644
index 0000000000..dbc25a0846
--- /dev/null
+++ b/quantum/encoder/tests/mock.h
@@ -0,0 +1,40 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/* Here, "pins" from 0 to 31 are allowed. */
+#define ENCODERS_PAD_A \
+    { 0 }
+#define ENCODERS_PAD_B \
+    { 1 }
+
+typedef uint8_t pin_t;
+
+extern bool pins[];
+extern bool pinIsInputHigh[];
+
+#define setPinInputHigh(pin) (mockSetPinInputHigh(pin))
+#define readPin(pin) (mockReadPin(pin))
+
+uint8_t mockSetPinInputHigh(pin_t pin);
+
+bool mockReadPin(pin_t pin);
+
+bool setPin(pin_t pin, bool val);
diff --git a/quantum/encoder/tests/mock_split.c b/quantum/encoder/tests/mock_split.c
new file mode 100644
index 0000000000..68bf3af599
--- /dev/null
+++ b/quantum/encoder/tests/mock_split.c
@@ -0,0 +1,36 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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 "mock_split.h"
+
+bool pins[32]           = {0};
+bool pinIsInputHigh[32] = {0};
+
+uint8_t mockSetPinInputHigh(pin_t pin) {
+    // dprintf("Setting pin %d input high.", pin);
+    pins[pin]           = true;
+    pinIsInputHigh[pin] = true;
+    return 0;
+}
+
+bool mockReadPin(pin_t pin) { return pins[pin]; }
+
+bool setPin(pin_t pin, bool val) {
+    pins[pin] = val;
+    return val;
+}
+
+void last_encoder_activity_trigger(void) {}
diff --git a/quantum/encoder/tests/mock_split.h b/quantum/encoder/tests/mock_split.h
new file mode 100644
index 0000000000..0ae62652f9
--- /dev/null
+++ b/quantum/encoder/tests/mock_split.h
@@ -0,0 +1,48 @@
+/* Copyright 2021 Balz Guenat
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#define SPLIT_KEYBOARD
+/* Here, "pins" from 0 to 31 are allowed. */
+#define ENCODERS_PAD_A \
+    { 0 }
+#define ENCODERS_PAD_B \
+    { 1 }
+#define ENCODERS_PAD_A_RIGHT \
+    { 2 }
+#define ENCODERS_PAD_B_RIGHT \
+    { 3 }
+
+typedef uint8_t pin_t;
+extern bool     isLeftHand;
+void            encoder_state_raw(uint8_t* slave_state);
+void            encoder_update_raw(uint8_t* slave_state);
+
+extern bool pins[];
+extern bool pinIsInputHigh[];
+
+#define setPinInputHigh(pin) (mockSetPinInputHigh(pin))
+#define readPin(pin) (mockReadPin(pin))
+
+uint8_t mockSetPinInputHigh(pin_t pin);
+
+bool mockReadPin(pin_t pin);
+
+bool setPin(pin_t pin, bool val);
diff --git a/quantum/encoder/tests/rules.mk b/quantum/encoder/tests/rules.mk
new file mode 100644
index 0000000000..b826ce3aed
--- /dev/null
+++ b/quantum/encoder/tests/rules.mk
@@ -0,0 +1,13 @@
+encoder_DEFS := -DENCODER_MOCK_SINGLE
+
+encoder_SRC := \
+	$(QUANTUM_PATH)/encoder/tests/mock.c \
+	$(QUANTUM_PATH)/encoder/tests/encoder_tests.cpp \
+	$(QUANTUM_PATH)/encoder.c
+
+encoder_split_DEFS := -DENCODER_MOCK_SPLIT
+
+encoder_split_SRC := \
+	$(QUANTUM_PATH)/encoder/tests/mock_split.c \
+	$(QUANTUM_PATH)/encoder/tests/encoder_tests_split.cpp \
+	$(QUANTUM_PATH)/encoder.c
diff --git a/quantum/encoder/tests/testlist.mk b/quantum/encoder/tests/testlist.mk
new file mode 100644
index 0000000000..1be9f4a054
--- /dev/null
+++ b/quantum/encoder/tests/testlist.mk
@@ -0,0 +1,3 @@
+TEST_LIST += \
+	encoder \
+	encoder_split
diff --git a/quantum/split_common/transport.h b/quantum/split_common/transport.h
index 1d4f6ed0cd..ab65ff56db 100644
--- a/quantum/split_common/transport.h
+++ b/quantum/split_common/transport.h
@@ -42,7 +42,11 @@ bool transport_execute_transaction(int8_t id, const void *initiator2target_buf,
 
 #ifdef ENCODER_ENABLE
 #    include "encoder.h"
-#    define NUMBER_OF_ENCODERS (sizeof((pin_t[])ENCODERS_PAD_A) / sizeof(pin_t))
+// if no pads for right half are defined, we assume the keyboard is symmetric (i.e. same pads)
+#    ifndef ENCODERS_PAD_A_RIGHT
+#        define ENCODERS_PAD_A_RIGHT ENCODERS_PAD_A
+#    endif
+#    define NUMBER_OF_ENCODERS ((sizeof((pin_t[])ENCODERS_PAD_A) + (sizeof((pin_t[])ENCODERS_PAD_A_RIGHT)) / sizeof(pin_t))
 #endif  // ENCODER_ENABLE
 
 #ifdef BACKLIGHT_ENABLE