Hid joystick interface (#4226)

* add support for hid gamepad interface
add documentation for HID joystick
Add joystick_task to read analog axes values even when no key is pressed or release. update doc
Update docs/feature_joystick.md
Manage pin setup and read to maintain matrix scan after analog read

* Incorporates patches and changes to HID reporting

There are some patches provided by @a-chol incorporated on this commit,
and also some changes I made to the HID Report structure.

The most interesting is the one dealing with number of buttons: Linux
doesn't seem to care, but Windows requires the HID structure to be byte
aligned (that's in the spec). So if one declares 8/16/32... buttons they
should not have any issues, but this is what happens when you have 9
buttons:

```
 bits |0|1|2|3|4|5|6|7|
      |*|*|*|*|*|*|*|*| axis 0 (report size 8)
      |*|*|*|*|*|*|*|*| ...
      |*|*|*|*|*|*|*|*|
      |*|*|*|*|*|*|*|*|
      |*|*|*|*|*|*|*|*|
      |*|*|*|*|*|*|*|*|
      |*|*|*|*|*|*|*|*| axis 6
      |*|*|*|*|*|*|*|*| first 8 buttons (report size 1)
      |*| | | | | | | | last of 9 buttons, not aligned
```

So for that I added a conditonal that will add a number of reports with
size 1 to make sure it aligns to the next multiple of 8. Those reports
send dummy inputs that don't do anything aside from aligning the data.

Tested on Linux, Windows 10 and Street Fighter (where the joystick is
recognized as direct-input)

* Add save and restore of each pin used in reading joystick (AVR).
Allow output pin to be JS_VIRTUAL_AXIS if the axis is connected to Vcc
instead of an output pin from the MCU.

Fix joystick report id

Fix broken v-usb hid joystick interface. Make it more resilient to unusual settings (none multiple of eight button count, 0 buttons or 0 axes)

Correct adc reading for multiple axes. Piecewise range conversion for uncentered raw value range. Input, output and ground pin configuration per axis.

Documentation fixes

* Fix port addressing for joystick analog read

* The other required set of changes
As per the PR, the changes still holding it up.
Add onekey for testing.
Fix ARM builds.
Fix device descriptor when either axes or buttons is zero.
Add compile-time check for at least one axis or button.
Move definition to try to fix conflict.
PR review comments.
qmk cformat

* avoid float functions to compute range mapping for axis adc reading

* Remove V-USB support for now. Updated docs accordingly.

* Update tmk_core/protocol/lufa/lufa.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update tmk_core/protocol/usb_descriptor.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update tmk_core/protocol/usb_descriptor.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update tmk_core/protocol/usb_descriptor.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Add support for joystick adc reading for stm32 MCUs. Fix joystick hid report sending for chibios

* Fix HID joystick report sending for ChibiOS.
Add one analog axis to the onekey:joystick keymap.
Fix pin state save and restore during joystick analog read for STM32
MCUs.

* Update tmk_core/protocol/chibios/usb_main.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update tmk_core/protocol/lufa/lufa.c

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Add missing mcuconf.h and halconf.h to onekey:joystick keymap.
Add suggested fixes from PR.

* Switch saveState and restoreState signature to use pin_t type.
onekey:joystick : add a second axis, virtual and programmatically animated.

* Update docs/feature_joystick.md

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Update docs/feature_joystick.md

Co-Authored-By: Ryan <fauxpark@gmail.com>

* Add PR corrections

* Remove halconf.h and mcuconf.h from onekey keymaps

* Change ADC_PIN to A0

Co-authored-by: achol <allecooll@hotmail.com>
Co-authored-by: José Júnior <jose.junior@gmail.com>
Co-authored-by: a-chol <achol@notamail.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>
Co-authored-by: Ryan <fauxpark@gmail.com>

common_features.mk

@@ -529,3 +529,10 @@ ifeq ($(strip $(AUTO_SHIFT_ENABLE)), yes)
         OPT_DEFS += -DAUTO_SHIFT_MODIFIERS
     endif
 endif
+
+ifeq ($(strip $(JOYSTICK_ENABLE)), yes)
+    OPT_DEFS += -DJOYSTICK_ENABLE
+    SRC += $(QUANTUM_DIR)/process_keycode/process_joystick.c
+    SRC += $(QUANTUM_DIR)/joystick.c
+    SRC += analog.c
+endif

docs/_summary.md

@@ -103,6 +103,7 @@
     * [DIP Switch](feature_dip_switch.md)
     * [Encoders](feature_encoders.md)
     * [Haptic Feedback](feature_haptic_feedback.md)
+    * [Joystick](feature_joystick.md)
     * [Proton C Conversion](proton_c_conversion.md)
     * [PS/2 Mouse](feature_ps2_mouse.md)
     * [Split Keyboard](feature_split_keyboard.md)

docs/feature_joystick.md

@@ -0,0 +1,145 @@
+## Joystick
+
+The keyboard can be made to be recognized as a joystick HID device by the operating system.
+
+This is enabled by adding the following to `rules.mk`:
+
+```makefile
+JOYSTICK_ENABLE = yes
+```
+
+!> Joystick support is not currently available on V-USB devices.
+
+The joystick feature provides two services:
+ * reading analog input devices (eg. potentiometers)
+ * sending gamepad HID reports
+
+Both services can be used without the other, depending on whether you just want to read a device but not send gamepad reports (for volume control for instance)
+or send gamepad reports based on values computed by the keyboard.
+
+### Analog Input
+
+An analog device such as a potentiometer found on a gamepad's analog axes is based on a [voltage divider](https://en.wikipedia.org/wiki/Voltage_divider).
+It is composed of three connectors linked to the ground, the power input and power output (usually the middle one). The power output holds the voltage that varies based on the position of the cursor,
+which value will be read using your MCU's [ADC](https://en.wikipedia.org/wiki/Analog-to-digital_converter).
+Depending on which pins are already used by your keyboard's matrix, the rest of the circuit can get a little bit more complicated,
+feeding the power input and ground connection through pins and using diodes to avoid bad interactions with the matrix scanning procedures.
+
+### Configuring the Joystick
+
+By default, two axes and eight buttons are defined. This can be changed in your `config.h`:
+
+```c
+// Max 32
+#define JOYSTICK_BUTTON_COUNT 16
+// Max 6: X, Y, Z, Rx, Ry, Rz
+#define JOYSTICK_AXES_COUNT 3
+```
+
+When defining axes for your joystick, you have to provide a definition array. You can do this from your keymap.c file.
+A joystick will either be read from an input pin that allows the use of the ADC, or can be virtual, so that its value is provided by your code.
+You have to define an array of type ''joystick_config_t'' and of proper size.
+
+There are three ways for your circuit to work with the ADC, that relies on the use of 1, 2 or 3 pins of the MCU:
+ * 1 pin: your analog device is directly connected to your device GND and VCC. The only pin used is the ADC pin of your choice.
+ * 2 pins: your analog device is powered through a pin that allows toggling it on or off. The other pin is used to read the input value through the ADC.
+ * 3 pins: both the power input and ground are connected to pins that must be set to a proper state before reading and restored afterwards.
+
+The configuration of each axis is performed using one of four macros:
+ * `JOYSTICK_AXIS_VIRTUAL`: no ADC reading must be performed, that value will be provided by keyboard/keymap-level code
+ * `JOYSTICK_AXIS_IN(INPUT_PIN, LOW, REST, HIGH)`: a voltage will be read on the provided pin, which must be an ADC-capable pin.
+ * `JOYSTICK_AXIS_IN_OUT(INPUT_PIN, OUTPUT_PIN, LOW, REST, HIGH)`: the provided `OUTPUT_PIN` will be set high before `INPUT_PIN` is read.
+ * `JOYSTICK_AXIS_IN_OUT_GROUND(INPUT_PIN, OUTPUT_PIN, GROUND_PIN, LOW, REST, HIGH)`: the `OUTPUT_PIN` will be set high and `GROUND_PIN` will be set low before reading from `INPUT_PIN`.
+
+In any case where an ADC reading takes place (when `INPUT_PIN` is provided), additional `LOW`, `REST` and `HIGH` parameters are used.
+These implement the calibration of the analog device by defining the range of read values that will be mapped to the lowest, resting position and highest possible value for the axis (-127 to 127).
+In practice, you have to provide the lowest/highest raw ADC reading, and the raw reading at resting position, when no deflection is applied. You can provide inverted `LOW` and `HIGH` to invert the axis.
+
+For instance, an axes configuration can be defined in the following way:
+
+```c
+//joystick config
+joystick_config_t joystick_axes[JOYSTICK_AXES_COUNT] = {
+    [0] = JOYSTICK_AXIS_IN_OUT_GROUND(A4, B0, A7, 900, 575, 285),
+    [1] = JOYSTICK_AXIS_VIRTUAL
+};
+```
+
+When the ADC reads 900 or higher, the returned axis value will be -127, whereas it will be 127 when the ADC reads 285 or lower. Zero is returned when 575 is read.
+
+In this example, the first axis will be read from the `A4` pin while `B0` is set high and `A7` is set low, using `analogReadPin()`, whereas the second axis will not be read.
+
+In order to give a value to the second axis, you can do so in any customizable entry point: as an action, in `process_record_user()` or in `matrix_scan_user()`, or even in `joystick_task()` which is called even when no key has been pressed.
+You assign a value by writing to `joystick_status.axes[axis_index]` a signed 8-bit value (ranging from -127 to 127). Then it is necessary to assign the flag `JS_UPDATED` to `joystick_status.status` in order for an updated HID report to be sent.
+
+The following example writes two axes based on keypad presses, with `KC_P5` as a precision modifier:
+
+```c
+#ifdef JOYSTICK_ENABLE
+static uint8_t precision_val = 70;
+static uint8_t axesFlags = 0;
+enum axes {
+    Precision = 1,
+    Axis1High = 2,
+    Axis1Low = 4,
+    Axis2High = 8,
+    Axis2Low = 16
+};
+#endif
+
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+    switch(keycode) {
+#ifdef JOYSTICK_ENABLE
+        // virtual joystick
+#    if JOYSTICK_AXES_COUNT > 1
+        case KC_P8:
+            if (record->event.pressed) {
+                axesFlags |= Axis2Low;
+            } else {
+                axesFlags &= ~Axis2Low;
+            }
+            joystick_status.status |= JS_UPDATED;
+            break;
+        case KC_P2:
+            if (record->event.pressed) {
+                axesFlags |= Axis2High;
+            } else {
+                axesFlags &= ~Axis2High;
+            }
+            joystick_status.status |= JS_UPDATED;
+            break;
+#    endif
+        case KC_P4:
+            if (record->event.pressed) {
+                axesFlags |= Axis1Low;
+            } else {
+                axesFlags &= ~Axis1Low;
+            }
+            joystick_status.status |= JS_UPDATED;
+            break;
+        case KC_P6:
+            if (record->event.pressed) {
+                axesFlags |= Axis1High;
+            } else {
+                axesFlags &= ~Axis1High;
+            }
+            joystick_status.status |= JS_UPDATED;
+            break;
+        case KC_P5:
+            if (record->event.pressed) {
+                axesFlags |= Precision;
+            } else {
+                axesFlags &= ~Precision;
+            }
+            joystick_status.status |= JS_UPDATED;
+            break;
+#endif
+    }
+    return true;
+}
+```
+
+### Triggering Joystick Buttons
+
+Joystick buttons are normal Quantum keycodes, defined as `JS_BUTTON0` to `JS_BUTTON31`, depending on the number of buttons you have configured.
+To trigger a joystick button, just add the corresponding keycode to your keymap.

drivers/avr/analog.c

@@ -97,10 +97,11 @@ uint8_t pinToMux(pin_t pin) {
 #endif
             // clang-format on
     }
+    return 0;
 }
 
 int16_t adc_read(uint8_t mux) {
-    uint8_t low;
+    uint16_t low;
 
     // Enable ADC and configure prescaler
     ADCSRA = _BV(ADEN) | ADC_PRESCALER;
@@ -128,5 +129,10 @@ int16_t adc_read(uint8_t mux) {
     // Must read LSB first
     low = ADCL;
     // Must read MSB only once!
-    return (ADCH << 8) | low;
+    low |= (ADCH << 8);
+
+    // turn off the ADC
+    ADCSRA &= ~(1 << ADEN);
+
+    return low;
 }

keyboards/handwired/onekey/keymaps/joystick/config.h

@@ -0,0 +1,3 @@
+#pragma once
+#define JOYSTICK_AXES_COUNT 2
+#define JOYSTICK_BUTTON_COUNT 1

keyboards/handwired/onekey/keymaps/joystick/keymap.c

@@ -0,0 +1,25 @@
+#include QMK_KEYBOARD_H
+
+#include "joystick.h"
+
+#ifndef ADC_PIN
+#    define ADC_PIN F6
+#endif
+
+const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
+  LAYOUT( JS_BUTTON0 )
+};
+
+void matrix_scan_user() {
+  int16_t val = (((uint32_t)timer_read()%5000 - 2500) * 255) / 5000;
+  if (val != joystick_status.axes[1]) {
+    joystick_status.axes[1] = val;
+    joystick_status.status |= JS_UPDATED;
+  }
+}
+
+//joystick config
+joystick_config_t joystick_axes[JOYSTICK_AXES_COUNT] = {
+    [0] = JOYSTICK_AXIS_IN(ADC_PIN, 0, 512, 1023)
+  , [1] = JOYSTICK_AXIS_VIRTUAL
+};

keyboards/handwired/onekey/keymaps/joystick/rules.mk

@@ -0,0 +1 @@
+JOYSTICK_ENABLE = yes

quantum/joystick.c

@@ -0,0 +1,13 @@
+#include "joystick.h"
+
+joystick_t joystick_status = {.buttons = {0},
+                              .axes =
+                                  {
+#if JOYSTICK_AXES_COUNT > 0
+                                      0
+#endif
+                                  },
+                              .status = 0};
+
+// array defining the reading of analog values for each axis
+__attribute__((weak)) joystick_config_t joystick_axes[JOYSTICK_AXES_COUNT] = {};

quantum/joystick.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#ifndef JOYSTICK_BUTTON_COUNT
+#    define JOYSTICK_BUTTON_COUNT 8
+#endif
+
+#ifndef JOYSTICK_AXES_COUNT
+#    define JOYSTICK_AXES_COUNT 4
+#endif
+
+#include "quantum.h"
+
+#include <stdint.h>
+
+// configure on input_pin of the joystick_axes array entry to JS_VIRTUAL_AXIS
+// to prevent it from being read from the ADC. This allows outputing forged axis value.
+//
+#define JS_VIRTUAL_AXIS 0xFF
+
+#define JOYSTICK_AXIS_VIRTUAL \
+    { JS_VIRTUAL_AXIS, JS_VIRTUAL_AXIS, JS_VIRTUAL_AXIS, 0, 1023 }
+#define JOYSTICK_AXIS_IN(INPUT_PIN, LOW, REST, HIGH) \
+    { JS_VIRTUAL_AXIS, INPUT_PIN, JS_VIRTUAL_AXIS, LOW, REST, HIGH }
+#define JOYSTICK_AXIS_IN_OUT(INPUT_PIN, OUTPUT_PIN, LOW, REST, HIGH) \
+    { OUTPUT_PIN, INPUT_PIN, JS_VIRTUAL_AXIS, LOW, REST, HIGH }
+#define JOYSTICK_AXIS_IN_OUT_GROUND(INPUT_PIN, OUTPUT_PIN, GROUND_PIN, LOW, REST, HIGH) \
+    { OUTPUT_PIN, INPUT_PIN, GROUND_PIN, LOW, REST, HIGH }
+
+typedef struct {
+    pin_t output_pin;
+    pin_t input_pin;
+    pin_t ground_pin;
+
+    // the AVR ADC offers 10 bit precision, with significant bits on the higher part
+    uint16_t min_digit;
+    uint16_t mid_digit;
+    uint16_t max_digit;
+} joystick_config_t;
+
+extern joystick_config_t joystick_axes[JOYSTICK_AXES_COUNT];
+
+enum joystick_status { JS_INITIALIZED = 1, JS_UPDATED = 2 };
+
+typedef struct {
+    uint8_t buttons[JOYSTICK_BUTTON_COUNT / 8 + 1];
+
+    int16_t axes[JOYSTICK_AXES_COUNT];
+    uint8_t status : 2;
+} joystick_t;
+
+extern joystick_t joystick_status;
+
+// to be implemented in the hid protocol library
+void send_joystick_packet(joystick_t *joystick);

quantum/process_keycode/process_joystick.c

@@ -0,0 +1,168 @@
+#include "joystick.h"
+#include "process_joystick.h"
+
+#include "analog.h"
+
+#include <string.h>
+#include <math.h>
+
+bool process_joystick_buttons(uint16_t keycode, keyrecord_t *record);
+
+bool process_joystick(uint16_t keycode, keyrecord_t *record) {
+    if (process_joystick_buttons(keycode, record) && (joystick_status.status & JS_UPDATED) > 0) {
+        send_joystick_packet(&joystick_status);
+        joystick_status.status &= ~JS_UPDATED;
+    }
+
+    return true;
+}
+
+__attribute__((weak))
+void joystick_task(void) {
+    if (process_joystick_analogread() && (joystick_status.status & JS_UPDATED)) {
+        send_joystick_packet(&joystick_status);
+        joystick_status.status &= ~JS_UPDATED;
+    }
+}
+
+bool process_joystick_buttons(uint16_t keycode, keyrecord_t *record) {
+    if (keycode < JS_BUTTON0 || keycode > JS_BUTTON_MAX) {
+        return true;
+    } else {
+        if (record->event.pressed) {
+            joystick_status.buttons[(keycode - JS_BUTTON0) / 8] |= 1 << (keycode % 8);
+        } else {
+            joystick_status.buttons[(keycode - JS_BUTTON0) / 8] &= ~(1 << (keycode % 8));
+        }
+
+        joystick_status.status |= JS_UPDATED;
+    }
+
+    return true;
+}
+
+uint16_t savePinState(pin_t pin) {
+#ifdef __AVR__
+    uint8_t pinNumber = pin & 0xF;
+    return ((PORTx_ADDRESS(pin) >> pinNumber) & 0x1) << 1 | ((DDRx_ADDRESS(pin) >> pinNumber) & 0x1);
+#elif defined(PROTOCOL_CHIBIOS)
+    /*
+    The pin configuration is backed up in the following format : 
+ bit  15    9  8   7   6  5  4   3     2    1 0
+      |unused|ODR|IDR|PUPDR|OSPEEDR|OTYPER|MODER|
+    */
+    return  (( PAL_PORT(pin)->MODER   >> (2*PAL_PAD(pin))) & 0x3)
+          | (((PAL_PORT(pin)->OTYPER  >> (1*PAL_PAD(pin))) & 0x1) << 2) 
+          | (((PAL_PORT(pin)->OSPEEDR >> (2*PAL_PAD(pin))) & 0x3) << 3)
+          | (((PAL_PORT(pin)->PUPDR   >> (2*PAL_PAD(pin))) & 0x3) << 5)
+          | (((PAL_PORT(pin)->IDR     >> (1*PAL_PAD(pin))) & 0x1) << 7)
+          | (((PAL_PORT(pin)->ODR     >> (1*PAL_PAD(pin))) & 0x1) << 8);
+#else
+    return 0;
+#endif
+}
+
+void restorePinState(pin_t pin, uint16_t restoreState) {
+#if defined(PROTOCOL_LUFA)
+    uint8_t pinNumber  = pin & 0xF;
+    PORTx_ADDRESS(pin) = (PORTx_ADDRESS(pin) & ~_BV(pinNumber)) | (((restoreState >> 1) & 0x1) << pinNumber);
+    DDRx_ADDRESS(pin)  = (DDRx_ADDRESS(pin) & ~_BV(pinNumber)) | ((restoreState & 0x1) << pinNumber);
+#elif defined(PROTOCOL_CHIBIOS)
+    PAL_PORT(pin)->MODER  =  (PAL_PORT(pin)->MODER   & ~(0x3<< (2*PAL_PAD(pin)))) | (restoreState & 0x3)     << (2*PAL_PAD(pin));
+    PAL_PORT(pin)->OTYPER =  (PAL_PORT(pin)->OTYPER  & ~(0x1<< (1*PAL_PAD(pin)))) | ((restoreState>>2) & 0x1) << (1*PAL_PAD(pin));
+    PAL_PORT(pin)->OSPEEDR=  (PAL_PORT(pin)->OSPEEDR & ~(0x3<< (2*PAL_PAD(pin)))) | ((restoreState>>3) & 0x3) << (2*PAL_PAD(pin));
+    PAL_PORT(pin)->PUPDR  =  (PAL_PORT(pin)->PUPDR   & ~(0x3<< (2*PAL_PAD(pin)))) | ((restoreState>>5) & 0x3) << (2*PAL_PAD(pin));
+    PAL_PORT(pin)->IDR    =  (PAL_PORT(pin)->IDR     & ~(0x1<< (1*PAL_PAD(pin)))) | ((restoreState>>7) & 0x1) << (1*PAL_PAD(pin));
+    PAL_PORT(pin)->ODR    =  (PAL_PORT(pin)->ODR     & ~(0x1<< (1*PAL_PAD(pin)))) | ((restoreState>>8) & 0x1) << (1*PAL_PAD(pin));
+#else
+    return;
+#endif
+}
+
+__attribute__((weak)) bool process_joystick_analogread() { return process_joystick_analogread_quantum(); }
+
+bool process_joystick_analogread_quantum() {
+#if JOYSTICK_AXES_COUNT > 0
+    for (int axis_index = 0; axis_index < JOYSTICK_AXES_COUNT; ++axis_index) {
+        if (joystick_axes[axis_index].input_pin == JS_VIRTUAL_AXIS) {
+            continue;
+        }
+
+        // save previous input pin status as well
+        uint16_t inputSavedState = savePinState(joystick_axes[axis_index].input_pin);
+
+        // disable pull-up resistor
+        writePinLow(joystick_axes[axis_index].input_pin);
+
+        // if pin was a pull-up input, we need to uncharge it by turning it low
+        // before making it a low input
+        setPinOutput(joystick_axes[axis_index].input_pin);
+
+        wait_us(10);
+
+        // save and apply output pin status
+        uint16_t outputSavedState = 0;
+        if (joystick_axes[axis_index].output_pin != JS_VIRTUAL_AXIS) {
+            // save previous output pin status
+            outputSavedState = savePinState(joystick_axes[axis_index].output_pin);
+
+            setPinOutput(joystick_axes[axis_index].output_pin);
+            writePinHigh(joystick_axes[axis_index].output_pin);
+        }
+
+        uint16_t groundSavedState = 0;
+        if (joystick_axes[axis_index].ground_pin != JS_VIRTUAL_AXIS) {
+            // save previous output pin status
+            groundSavedState = savePinState(joystick_axes[axis_index].ground_pin);
+
+            setPinOutput(joystick_axes[axis_index].ground_pin);
+            writePinLow(joystick_axes[axis_index].ground_pin);
+        }
+
+        wait_us(10);
+
+        setPinInput(joystick_axes[axis_index].input_pin);
+
+        wait_us(10);
+
+#    if defined(__AVR__) || defined(PROTOCOL_CHIBIOS)
+        int16_t axis_val = analogReadPin(joystick_axes[axis_index].input_pin);
+#    else
+        // default to resting position
+        int16_t axis_val = joystick_axes[axis_index].mid_digit;
+#    endif
+
+        //test the converted value against the lower range
+        int32_t ref = joystick_axes[axis_index].mid_digit;
+        int32_t range = joystick_axes[axis_index].min_digit;
+        int32_t ranged_val = ((axis_val - ref) * -127) / (range - ref) ;
+
+        if (ranged_val > 0) {
+            //the value is in the higher range
+            range = joystick_axes[axis_index].max_digit;
+            ranged_val = ((axis_val - ref) * 127) / (range - ref);
+        }
+        
+        //clamp the result in the valid range
+        ranged_val = ranged_val < -127 ? -127 : ranged_val;
+        ranged_val = ranged_val > 127 ? 127 : ranged_val;
+        
+        if (ranged_val != joystick_status.axes[axis_index]) {
+            joystick_status.axes[axis_index] = ranged_val;
+            joystick_status.status |= JS_UPDATED;
+        }
+
+        // restore output, ground and input status
+        if (joystick_axes[axis_index].output_pin != JS_VIRTUAL_AXIS) {
+            restorePinState(joystick_axes[axis_index].output_pin, outputSavedState);
+        }
+        if (joystick_axes[axis_index].ground_pin != JS_VIRTUAL_AXIS) {
+            restorePinState(joystick_axes[axis_index].ground_pin, groundSavedState);
+        }
+
+        restorePinState(joystick_axes[axis_index].input_pin, inputSavedState);
+    }
+
+#endif
+    return true;
+}

quantum/process_keycode/process_joystick.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+#include "quantum.h"
+
+bool process_joystick(uint16_t keycode, keyrecord_t *record);
+
+void joystick_task(void);
+
+bool process_joystick_analogread(void);
+bool process_joystick_analogread_quantum(void);

quantum/quantum.c

@@ -276,6 +276,9 @@ bool process_record_quantum(keyrecord_t *record) {
 #endif
 #if defined(RGBLIGHT_ENABLE) || defined(RGB_MATRIX_ENABLE)
             process_rgb(keycode, record) &&
+#endif
+#ifdef JOYSTICK_ENABLE
+            process_joystick(keycode, record) &&
 #endif
             true)) {
         return false;

quantum/quantum.h

@@ -142,6 +142,10 @@ extern layer_state_t layer_state;
 #    include "process_magic.h"
 #endif
 
+#ifdef JOYSTICK_ENABLE
+#    include "process_joystick.h"
+#endif
+
 #ifdef GRAVE_ESC_ENABLE
 #    include "process_grave_esc.h"
 #endif

quantum/quantum_keycodes.h

@@ -512,6 +512,41 @@ enum quantum_keycodes {
     DYN_MACRO_PLAY1,
     DYN_MACRO_PLAY2,
 
+    JS_BUTTON0,
+    JS_BUTTON_MIN = JS_BUTTON0,
+    JS_BUTTON1,
+    JS_BUTTON2,
+    JS_BUTTON3,
+    JS_BUTTON4,
+    JS_BUTTON5,
+    JS_BUTTON6,
+    JS_BUTTON7,
+    JS_BUTTON8,
+    JS_BUTTON9,
+    JS_BUTTON10,
+    JS_BUTTON11,
+    JS_BUTTON12,
+    JS_BUTTON13,
+    JS_BUTTON14,
+    JS_BUTTON15,
+    JS_BUTTON16,
+    JS_BUTTON17,
+    JS_BUTTON18,
+    JS_BUTTON19,
+    JS_BUTTON20,
+    JS_BUTTON21,
+    JS_BUTTON22,
+    JS_BUTTON23,
+    JS_BUTTON24,
+    JS_BUTTON25,
+    JS_BUTTON26,
+    JS_BUTTON27,
+    JS_BUTTON28,
+    JS_BUTTON29,
+    JS_BUTTON30,
+    JS_BUTTON31,
+    JS_BUTTON_MAX = JS_BUTTON31,
+
     // always leave at the end
     SAFE_RANGE
 };

tmk_core/common/keyboard.c

@@ -74,6 +74,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifdef MIDI_ENABLE
 #    include "process_midi.h"
 #endif
+#ifdef JOYSTICK_ENABLE
+#    include "process_joystick.h"
+#endif
 #ifdef HD44780_ENABLE
 #    include "hd44780.h"
 #endif
@@ -420,6 +423,10 @@ MATRIX_LOOP_END:
     }
 #endif
 
+#ifdef JOYSTICK_ENABLE
+    joystick_task();
+#endif
+
     // update LED
     if (led_status != host_keyboard_leds()) {
         led_status = host_keyboard_leds();

tmk_core/common/report.h

@@ -29,7 +29,8 @@ enum hid_report_ids {
     REPORT_ID_MOUSE,
     REPORT_ID_SYSTEM,
     REPORT_ID_CONSUMER,
-    REPORT_ID_NKRO
+    REPORT_ID_NKRO,
+    REPORT_ID_JOYSTICK
 };
 
 /* Mouse buttons */
@@ -189,6 +190,16 @@ typedef struct {
     int8_t  h;
 } __attribute__((packed)) report_mouse_t;
 
+typedef struct {
+#if JOYSTICK_AXES_COUNT > 0
+    int8_t axes[JOYSTICK_AXES_COUNT];
+#endif
+
+#if JOYSTICK_BUTTON_COUNT > 0
+    uint8_t buttons[(JOYSTICK_BUTTON_COUNT - 1) / 8 + 1];
+#endif
+} __attribute__((packed)) joystick_report_t;
+
 /* keycode to system usage */
 static inline uint16_t KEYCODE2SYSTEM(uint8_t key) {
     switch (key) {

tmk_core/protocol/chibios/usb_main.c

@@ -47,6 +47,10 @@
 extern keymap_config_t keymap_config;
 #endif
 
+#ifdef JOYSTICK_ENABLE
+#    include "joystick.h"
+#endif
+
 /* ---------------------------------------------------------
  *       Global interface variables and declarations
  * ---------------------------------------------------------
@@ -246,6 +250,9 @@ typedef struct {
 #endif
 #ifdef VIRTSER_ENABLE
             usb_driver_config_t serial_driver;
+#endif
+#ifdef JOYSTICK_ENABLE
+            usb_driver_config_t joystick_driver;
 #endif
         };
         usb_driver_config_t array[0];
@@ -283,6 +290,14 @@ static usb_driver_configs_t drivers = {
 #    define CDC_OUT_MODE USB_EP_MODE_TYPE_BULK
     .serial_driver = QMK_USB_DRIVER_CONFIG(CDC, CDC_NOTIFICATION_EPNUM, false),
 #endif
+
+#ifdef JOYSTICK_ENABLE
+#    define JOYSTICK_IN_CAPACITY 4
+#    define JOYSTICK_OUT_CAPACITY 4
+#    define JOYSTICK_IN_MODE USB_EP_MODE_TYPE_BULK
+#    define JOYSTICK_OUT_MODE USB_EP_MODE_TYPE_BULK
+    .joystick_driver = QMK_USB_DRIVER_CONFIG(JOYSTICK, 0, false),
+#endif
 };
 
 #define NUM_USB_DRIVERS (sizeof(drivers) / sizeof(usb_driver_config_t))
@@ -867,3 +882,57 @@ void virtser_task(void) {
 }
 
 #endif
+
+#ifdef JOYSTICK_ENABLE
+
+void send_joystick_packet(joystick_t *joystick) {
+    joystick_report_t rep = {
+#    if JOYSTICK_AXES_COUNT > 0
+        .axes = {joystick->axes[0],
+
+#        if JOYSTICK_AXES_COUNT >= 2
+                 joystick->axes[1],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 3
+                 joystick->axes[2],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 4
+                 joystick->axes[3],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 5
+                 joystick->axes[4],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 6
+                 joystick->axes[5],
+#        endif
+        },
+#    endif  // JOYSTICK_AXES_COUNT>0
+
+#    if JOYSTICK_BUTTON_COUNT > 0
+        .buttons = {joystick->buttons[0],
+
+#        if JOYSTICK_BUTTON_COUNT > 8
+                    joystick->buttons[1],
+#        endif
+#        if JOYSTICK_BUTTON_COUNT > 16
+                    joystick->buttons[2],
+#        endif
+#        if JOYSTICK_BUTTON_COUNT > 24
+                    joystick->buttons[3],
+#        endif
+        }
+#    endif  // JOYSTICK_BUTTON_COUNT>0
+    };
+
+    // chnWrite(&drivers.joystick_driver.driver, (uint8_t *)&rep, sizeof(rep));
+    osalSysLock();
+    if (usbGetDriverStateI(&USB_DRIVER) != USB_ACTIVE) {
+        osalSysUnlock();
+        return;
+    }
+
+    usbStartTransmitI(&USB_DRIVER, JOYSTICK_IN_EPNUM, (uint8_t *)&rep, sizeof(joystick_report_t));
+    osalSysUnlock();
+}
+
+#endif

tmk_core/protocol/lufa/lufa.c

@@ -85,6 +85,10 @@ extern keymap_config_t keymap_config;
 #    include "raw_hid.h"
 #endif
 
+#ifdef JOYSTICK_ENABLE
+#    include "joystick.h"
+#endif
+
 uint8_t keyboard_idle = 0;
 /* 0: Boot Protocol, 1: Report Protocol(default) */
 uint8_t        keyboard_protocol  = 1;
@@ -263,6 +267,66 @@ static void Console_Task(void) {
 }
 #endif
 
+/*******************************************************************************
+ * Joystick
+ ******************************************************************************/
+#ifdef JOYSTICK_ENABLE
+void send_joystick_packet(joystick_t *joystick) {
+    uint8_t timeout = 255;
+
+    joystick_report_t r = {
+#    if JOYSTICK_AXES_COUNT > 0
+        .axes = {joystick->axes[0],
+
+#        if JOYSTICK_AXES_COUNT >= 2
+                 joystick->axes[1],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 3
+                 joystick->axes[2],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 4
+                 joystick->axes[3],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 5
+                 joystick->axes[4],
+#        endif
+#        if JOYSTICK_AXES_COUNT >= 6
+                 joystick->axes[5],
+#        endif
+        },
+#    endif  // JOYSTICK_AXES_COUNT>0
+
+#    if JOYSTICK_BUTTON_COUNT > 0
+        .buttons = {joystick->buttons[0],
+
+#        if JOYSTICK_BUTTON_COUNT > 8
+                    joystick->buttons[1],
+#        endif
+#        if JOYSTICK_BUTTON_COUNT > 16
+                    joystick->buttons[2],
+#        endif
+#        if JOYSTICK_BUTTON_COUNT > 24
+                    joystick->buttons[3],
+#        endif
+        }
+#    endif  // JOYSTICK_BUTTON_COUNT>0
+    };
+
+    /* Select the Joystick Report Endpoint */
+    Endpoint_SelectEndpoint(JOYSTICK_IN_EPNUM);
+
+    /* Check if write ready for a polling interval around 10ms */
+    while (timeout-- && !Endpoint_IsReadWriteAllowed()) _delay_us(40);
+    if (!Endpoint_IsReadWriteAllowed()) return;
+
+    /* Write Joystick Report Data */
+    Endpoint_Write_Stream_LE(&r, sizeof(joystick_report_t), NULL);
+
+    /* Finalize the stream transfer to send the last packet */
+    Endpoint_ClearIN();
+}
+#endif
+
 /*******************************************************************************
  * USB Events
  ******************************************************************************/
@@ -411,6 +475,9 @@ void EVENT_USB_Device_ConfigurationChanged(void) {
     ConfigSuccess &= Endpoint_ConfigureEndpoint((CDC_OUT_EPNUM | ENDPOINT_DIR_OUT), EP_TYPE_BULK, CDC_EPSIZE, 1);
     ConfigSuccess &= Endpoint_ConfigureEndpoint((CDC_IN_EPNUM | ENDPOINT_DIR_IN), EP_TYPE_BULK, CDC_EPSIZE, 1);
 #endif
+#ifdef JOYSTICK_ENABLE
+    ConfigSuccess &= ENDPOINT_CONFIG(JOYSTICK_IN_EPNUM, EP_TYPE_INTERRUPT, ENDPOINT_DIR_IN, JOYSTICK_EPSIZE, ENDPOINT_BANK_SINGLE);
+#endif
 }
 
 /* FIXME: Expose this table in the docs somehow

tmk_core/protocol/usb_descriptor.c

@@ -279,6 +279,63 @@ const USB_Descriptor_HIDReport_Datatype_t PROGMEM ConsoleReport[] = {
 };
 #endif
 
+#ifdef JOYSTICK_ENABLE
+#    if JOYSTICK_AXES_COUNT == 0 && JOYSTICK_BUTTON_COUNT == 0
+#        error Need at least one axis or button for joystick
+#    endif
+const USB_Descriptor_HIDReport_Datatype_t PROGMEM JoystickReport[] = {
+    HID_RI_USAGE_PAGE(8, 0x01),         // Generic Desktop
+    HID_RI_USAGE(8, 0x04),              // Joystick
+    HID_RI_COLLECTION(8, 0x01),         // Application
+        HID_RI_COLLECTION(8, 0x00),     // Physical
+            HID_RI_USAGE_PAGE(8, 0x01), // Generic Desktop
+#    if JOYSTICK_AXES_COUNT >= 1
+            HID_RI_USAGE(8, 0x30),      // X
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 2
+            HID_RI_USAGE(8, 0x31),      // Y
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 3
+            HID_RI_USAGE(8, 0x32),      // Z
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 4
+            HID_RI_USAGE(8, 0x33),      // Rx
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 5
+            HID_RI_USAGE(8, 0x34),      // Ry
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 6
+            HID_RI_USAGE(8, 0x35),      // Rz
+#    endif
+#    if JOYSTICK_AXES_COUNT >= 1
+            HID_RI_LOGICAL_MINIMUM(8, -127),
+            HID_RI_LOGICAL_MAXIMUM(8, 127),
+            HID_RI_REPORT_COUNT(8, JOYSTICK_AXES_COUNT),
+            HID_RI_REPORT_SIZE(8, 0x08),
+            HID_RI_INPUT(8, HID_IOF_DATA | HID_IOF_VARIABLE | HID_IOF_ABSOLUTE),
+#    endif
+
+#    if JOYSTICK_BUTTON_COUNT >= 1
+            HID_RI_USAGE_PAGE(8, 0x09), // Button
+            HID_RI_USAGE_MINIMUM(8, 0x01),
+            HID_RI_USAGE_MAXIMUM(8, JOYSTICK_BUTTON_COUNT),
+            HID_RI_LOGICAL_MINIMUM(8, 0x00),
+            HID_RI_LOGICAL_MAXIMUM(8, 0x01),
+            HID_RI_REPORT_COUNT(8, JOYSTICK_BUTTON_COUNT),
+            HID_RI_REPORT_SIZE(8, 0x01),
+            HID_RI_INPUT(8, HID_IOF_DATA | HID_IOF_VARIABLE | HID_IOF_ABSOLUTE),
+
+#        if (JOYSTICK_BUTTON_COUNT % 8) != 0
+            HID_RI_REPORT_COUNT(8, 8 - (JOYSTICK_BUTTON_COUNT % 8)),
+            HID_RI_REPORT_SIZE(8, 0x01),
+            HID_RI_INPUT(8, HID_IOF_CONSTANT),
+#        endif
+#    endif
+        HID_RI_END_COLLECTION(0),
+    HID_RI_END_COLLECTION(0)
+};
+#endif
+
 /*
  * Device descriptor
  */
@@ -288,7 +345,7 @@ const USB_Descriptor_Device_t PROGMEM DeviceDescriptor = {
         .Type                   = DTYPE_Device
     },
     .USBSpecification           = VERSION_BCD(1, 1, 0),
-
+    
 #if VIRTSER_ENABLE
     .Class                      = USB_CSCP_IADDeviceClass,
     .SubClass                   = USB_CSCP_IADDeviceSubclass,
@@ -813,6 +870,46 @@ const USB_Descriptor_Configuration_t PROGMEM ConfigurationDescriptor = {
         .PollingIntervalMS      = 0x05
     },
 #endif
+
+    /*
+     * Joystick
+     */
+#ifdef JOYSTICK_ENABLE
+    .Joystick_Interface = {
+        .Header = {
+            .Size               = sizeof(USB_Descriptor_Interface_t),
+            .Type               = DTYPE_Interface
+        },
+        .InterfaceNumber        = JOYSTICK_INTERFACE,
+        .AlternateSetting       = 0x00,
+        .TotalEndpoints         = 1,
+        .Class                  = HID_CSCP_HIDClass,
+        .SubClass               = HID_CSCP_NonBootSubclass,
+        .Protocol               = HID_CSCP_NonBootProtocol,
+        .InterfaceStrIndex      = NO_DESCRIPTOR
+    },
+    .Joystick_HID = {
+        .Header = {
+            .Size               = sizeof(USB_HID_Descriptor_HID_t),
+            .Type               = HID_DTYPE_HID
+        },
+        .HIDSpec                = VERSION_BCD(1, 1, 1),
+        .CountryCode            = 0x00,
+        .TotalReportDescriptors = 1,
+        .HIDReportType          = HID_DTYPE_Report,
+        .HIDReportLength        = sizeof(JoystickReport)
+    },
+    .Joystick_INEndpoint = {
+        .Header = {
+            .Size               = sizeof(USB_Descriptor_Endpoint_t),
+            .Type               = DTYPE_Endpoint
+        },
+        .EndpointAddress        = (ENDPOINT_DIR_IN | JOYSTICK_IN_EPNUM),
+        .Attributes             = (EP_TYPE_INTERRUPT | ENDPOINT_ATTR_NO_SYNC | ENDPOINT_USAGE_DATA),
+        .EndpointSize           = JOYSTICK_EPSIZE,
+        .PollingIntervalMS      = USB_POLLING_INTERVAL_MS
+    }
+#endif
 };
 
 /*
@@ -945,6 +1042,12 @@ uint16_t get_usb_descriptor(const uint16_t wValue, const uint16_t wIndex, const
 
                     break;
 #endif
+#ifdef JOYSTICK_ENABLE
+                case JOYSTICK_INTERFACE:
+                    Address = &ConfigurationDescriptor.Joystick_HID;
+                    Size    = sizeof(USB_HID_Descriptor_HID_t);
+                    break;
+#endif
             }
 
             break;
@@ -989,6 +1092,12 @@ uint16_t get_usb_descriptor(const uint16_t wValue, const uint16_t wIndex, const
 
                     break;
 #endif
+#ifdef JOYSTICK_ENABLE
+                case JOYSTICK_INTERFACE:
+                    Address = &JoystickReport;
+                    Size    = sizeof(JoystickReport);
+                    break;
+#endif
             }
 
             break;

tmk_core/protocol/usb_descriptor.h

@@ -123,6 +123,13 @@ typedef struct {
     USB_Descriptor_Endpoint_t  CDC_DataOutEndpoint;
     USB_Descriptor_Endpoint_t  CDC_DataInEndpoint;
 #endif
+
+#ifdef JOYSTICK_ENABLE
+    // Joystick HID Interface
+    USB_Descriptor_Interface_t Joystick_Interface;
+    USB_HID_Descriptor_HID_t   Joystick_HID;
+    USB_Descriptor_Endpoint_t  Joystick_INEndpoint;
+#endif
 } USB_Descriptor_Configuration_t;
 
 /*
@@ -164,6 +171,9 @@ enum usb_interfaces {
     CDI_INTERFACE,
 #endif
 
+#if defined(JOYSTICK_ENABLE)
+    JOYSTICK_INTERFACE,
+#endif
     TOTAL_INTERFACES
 };
 
@@ -219,6 +229,10 @@ enum usb_endpoints {
     CDC_IN_EPNUM           = NEXT_EPNUM,
     CDC_OUT_EPNUM          = NEXT_EPNUM,
 #endif
+#ifdef JOYSTICK_ENABLE
+    JOYSTICK_IN_EPNUM  = NEXT_EPNUM,
+    JOYSTICK_OUT_EPNUM = NEXT_EPNUM,
+#endif
 };
 
 #ifdef PROTOCOL_LUFA
@@ -243,6 +257,7 @@ enum usb_endpoints {
 #define MIDI_STREAM_EPSIZE 64
 #define CDC_NOTIFICATION_EPSIZE 8
 #define CDC_EPSIZE 16
+#define JOYSTICK_EPSIZE 8
 
 uint16_t get_usb_descriptor(const uint16_t wValue, const uint16_t wIndex, const void** const DescriptorAddress);
 #endif