Initial potentiometer support

builddefs/common_features.mk

@@ -905,6 +905,10 @@ ifeq ($(strip $(ENCODER_ENABLE)), yes)
     endif
 endif
 
+ifeq ($(strip $(POTENTIOMETER_ENABLE)), yes)
+    ANALOG_DRIVER_REQUIRED = yes
+endif
+
 VALID_WS2812_DRIVER_TYPES := bitbang custom i2c pwm spi vendor
 
 WS2812_DRIVER ?= bitbang

builddefs/generic_features.mk

@@ -40,6 +40,7 @@ GENERIC_FEATURES = \
     MOUSEKEY \
     MUSIC \
     OS_DETECTION \
+    POTENTIOMETER \
     PROGRAMMABLE_BUTTON \
     REPEAT_KEY \
     SECURE \

data/mappings/info_config.hjson

@@ -117,6 +117,9 @@
     "ONESHOT_TIMEOUT": {"info_key": "oneshot.timeout", "value_type": "int"},
     "ONESHOT_TAP_TOGGLE": {"info_key": "oneshot.tap_toggle", "value_type": "int"},
 
+    // Potentiometer
+    "POTENTIOMETER_PINS": {"info_key": "potentiometer.pins", "value_type": "array"},
+
     // PS/2
     "PS2_CLOCK_PIN": {"info_key": "ps2.clock_pin"},
     "PS2_DATA_PIN": {"info_key": "ps2.data_pin"},

data/mappings/info_rules.hjson

@@ -32,6 +32,7 @@
     "NO_USB_STARTUP_CHECK": {"info_key": "usb.no_startup_check", "value_type": "bool"},
     "PIN_COMPATIBLE": {"info_key": "pin_compatible"},
     "PLATFORM_KEY": {"info_key": "platform_key", "to_json": false},
+    "POTENTIOMETER_ENABLE": {"info_key": "potentiometer.enabled", "value_type": "bool"},
     "PS2_DRIVER": {"info_key": "ps2.driver"},
     "PS2_ENABLE": {"info_key": "ps2.enabled", "value_type": "bool"},
     "PS2_MOUSE_ENABLE": {"info_key": "ps2.mouse_enabled", "value_type": "bool"},

data/schemas/keyboard.jsonschema

@@ -417,6 +417,13 @@
                 "timeout": {"$ref": "qmk.definitions.v1#/unsigned_int"}
             }
         },
+        "potentiometer": {
+            "type": "object",
+            "properties": {
+                "enabled": {"type": "boolean"},
+                "pins": {"$ref": "qmk.definitions.v1#/mcu_pin_array"}
+            }
+        },
         "led_matrix": {
             "type": "object",
             "properties": {

docs/_summary.md

@@ -123,6 +123,7 @@
     * [LED Indicators](feature_led_indicators.md)
     * [MIDI](feature_midi.md)
     * [Pointing Device](feature_pointing_device.md)
+    * [Potentiometer](feature_potentiometers.md)
     * [PS/2 Mouse](feature_ps2_mouse.md)
     * [Split Keyboard](feature_split_keyboard.md)
     * [Stenography](feature_stenography.md)

docs/feature_potentiometers.md

@@ -0,0 +1,35 @@
+# Potentiometers
+
+Add this to your `rules.mk`:
+
+```make
+POTENTIOMETER_ENABLE = yes
+```
+
+and this to your `config.h`:
+
+```c
+#define POTENTIOMETER_PINS { B0 }
+```
+
+## Callbacks
+
+The callback functions can be inserted into your `<keyboard>.c`:
+
+```c
+bool potentiometer_update_kb(uint8_t index, uint16_t value) {
+    if (!potentiometer_update_user(index, value)) {
+        midi_send_cc(&midi_device, 2, 0x3E, 0x7F + (value >> 3));
+    }
+    return true;
+}
+```
+
+or `keymap.c`:
+
+```c
+bool potentiometer_update_user(uint8_t index, uint16_t value) {
+    midi_send_cc(&midi_device, 2, 0x3E, 0x7F + (value >> 3));
+    return false;
+}
+```

docs/reference_info_json.md

@@ -478,6 +478,17 @@ Configures [One Shot keys](one_shot_keys.md).
     * `timeout`
         * The amount of time before the key is released in milliseconds.
 
+## Potentiometer :id=potentiometer
+
+Configures the [Potentiometer](feature_Potentiometers.md) feature.
+
+* `potentiometer`
+    * `enabled`
+        * Enable the Potentiometer feature.
+        * Default: `false`
+    * `pins` (Required)
+        * The GPIO pin(s) connected to the Potentiometer(s).
+
 ## PS/2 :id=ps2
 
 Configures the [PS/2](feature_ps2_mouse.md) feature.

keyboards/gmmk/numpad/config.h

@@ -17,7 +17,7 @@
 
 #pragma once
 
-#define SLIDER_PIN B0
+#define POTENTIOMETER_PINS { B0 }
 #define MIDI_ADVANCED
 
 #define LOCKING_SUPPORT_ENABLE

keyboards/gmmk/numpad/keymaps/default/keymap.c

@@ -16,8 +16,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include QMK_KEYBOARD_H
-#include "analog.h"
-#include "qmk_midi.h"
 
 // clang-format off
 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
@@ -43,18 +41,3 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
     RGB_TOG,                         QK_BOOT
   )
 };
-
-// Potentiometer Slider, MIDI Control
-
-uint8_t divisor = 0;
-
-void slider(void) {
-    if (divisor++) { /* only run the slider function 1/256 times it's called */
-        return;
-    }
-    midi_send_cc(&midi_device, 2, 0x3E, 0x7F + (analogReadPin(SLIDER_PIN) >> 3));
-}
-
-void housekeeping_task_user(void) {
-    slider();
-}

keyboards/gmmk/numpad/keymaps/via/keymap.c

@@ -13,8 +13,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include QMK_KEYBOARD_H
-#include "analog.h"
-#include "qmk_midi.h"
 
 // clang-format off
 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
@@ -62,18 +60,3 @@ const uint16_t PROGMEM encoder_map[][NUM_ENCODERS][NUM_DIRECTIONS] = {
     [2] = { ENCODER_CCW_CW(KC_VOLD, KC_VOLU) },
     [3] = { ENCODER_CCW_CW(KC_VOLD, KC_VOLU) }
 };
-
-// Potentiometer Slider, MIDI Control
-
-uint8_t divisor = 0;
-
-void slider(void) {
-    if (divisor++) { /* only run the slider function 1/256 times it's called */
-        return;
-    }
-    midi_send_cc(&midi_device, 2, 0x3E, 0x7F + (analogReadPin(SLIDER_PIN) >> 3));
-}
-
-void housekeeping_task_user(void) {
-    slider();
-}

keyboards/gmmk/numpad/numpad.c

@@ -16,6 +16,7 @@
  */
 
 #include "quantum.h"
+#include "qmk_midi.h"
 
 #ifdef RGB_MATRIX_ENABLE
 
@@ -117,3 +118,10 @@ void keyboard_pre_init_user(void) {
 #    endif
 
 #endif
+
+bool potentiometer_update_kb(uint8_t index, uint16_t value) {
+    if (!potentiometer_update_user(index, value)) {
+        midi_send_cc(&midi_device, 2, 0x3E, 0x7F + value);
+    }
+    return true;
+}

keyboards/gmmk/numpad/rules.mk

@@ -13,11 +13,10 @@ AUDIO_ENABLE = no           # Audio output
 ENCODER_ENABLE = yes
 KEYBOARD_SHARED_EP = yes
 MIDI_ENABLE = yes
+POTENTIOMETER_ENABLE = yes
 
 RGB_MATRIX_ENABLE = yes
 
 LTO_ENABLE = yes
 
-ANALOG_DRIVER_REQUIRED = yes
-
 SRC += matrix.c

quantum/keyboard.c

@@ -60,6 +60,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifdef ENCODER_ENABLE
 #    include "encoder.h"
 #endif
+#ifdef POTENTIOMETER_ENABLE
+#    include "potentiometer.h"
+#endif
 #ifdef HAPTIC_ENABLE
 #    include "haptic.h"
 #endif
@@ -669,6 +672,12 @@ void keyboard_task(void) {
     }
 #endif
 
+#ifdef POTENTIOMETER_ENABLE
+    if (potentiometer_task()) {
+        activity_has_occurred = true;
+    }
+#endif
+
 #ifdef POINTING_DEVICE_ENABLE
     if (pointing_device_task()) {
         last_pointing_device_activity_trigger();

quantum/potentiometer.c

@@ -0,0 +1,90 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "potentiometer.h"
+#include "gpio.h"
+#include "util.h"
+#include "timer.h"
+#include "analog.h"
+
+#ifndef POTENTIOMETER_THROTTLE_MS
+#    define POTENTIOMETER_THROTTLE_MS 1
+#endif
+
+#ifndef POTENTIOMETER_OUTPUT_MIN_VALUE
+#    define POTENTIOMETER_OUTPUT_MIN_VALUE 0
+#endif
+#ifndef POTENTIOMETER_OUTPUT_MAX_VALUE
+#    define POTENTIOMETER_OUTPUT_MAX_VALUE 127
+#endif
+#ifndef POTENTIOMETER_ADC_MIN_VALUE
+#    define POTENTIOMETER_ADC_MIN_VALUE 0
+#endif
+#ifndef POTENTIOMETER_ADC_MAX_VALUE
+#    define POTENTIOMETER_ADC_MAX_VALUE (1 << 10)
+#endif
+
+static pin_t potentiometer_pads[] = POTENTIOMETER_PINS;
+#define NUM_POTENTIOMETERS (ARRAY_SIZE(potentiometer_pads))
+
+__attribute__((weak)) bool potentiometer_update_user(uint8_t index, uint16_t value) {
+    return true;
+}
+
+__attribute__((weak)) bool potentiometer_update_kb(uint8_t index, uint16_t value) {
+    return potentiometer_update_user(index, value);
+}
+
+__attribute__((weak)) bool potentiometer_throttle_task(void) {
+#if (POTENTIOMETER_THROTTLE_MS > 0)
+    static uint32_t last_exec = 0;
+    if (timer_elapsed32(last_exec) < POTENTIOMETER_THROTTLE_MS) {
+        return false;
+    }
+    last_exec = timer_read32();
+#endif
+    return true;
+}
+
+__attribute__((weak)) uint16_t potentiometer_map(uint8_t index, uint16_t value) {
+    (void)index;
+
+    uint32_t a   = POTENTIOMETER_OUTPUT_MIN_VALUE;
+    uint32_t b   = POTENTIOMETER_OUTPUT_MAX_VALUE;
+    uint32_t min = POTENTIOMETER_ADC_MIN_VALUE;
+    uint32_t max = POTENTIOMETER_ADC_MAX_VALUE;
+
+    // Scale value to min/max using the adc range
+    return ((b - a) * (value - min) / (max - min)) + a;
+}
+
+__attribute__((weak)) bool potentiometer_filter(uint8_t index, uint16_t value) {
+    // ADC currently limited to max of 12 bits - init to max 16 ensures
+    // we can correctly capture even a raw first sample at max adc bounds
+    static bool potentiometer_state[NUM_POTENTIOMETERS] = {UINT16_MAX};
+
+    if (value == potentiometer_state[index]) {
+        return false;
+    }
+
+    potentiometer_state[index] = value;
+    return true;
+}
+
+bool potentiometer_task(void) {
+    if (!potentiometer_throttle_task()) {
+        return false;
+    }
+
+    bool changed = false;
+    for (uint8_t index = 0; index < NUM_POTENTIOMETERS; index++) {
+        uint16_t raw   = analogReadPin(potentiometer_pads[index]);
+        uint16_t value = potentiometer_map(index, raw);
+        if (potentiometer_filter(index, value)) {
+            changed |= true;
+
+            potentiometer_update_kb(index, value);
+        }
+    }
+
+    return changed;
+}

quantum/potentiometer.h

@@ -0,0 +1,18 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/** \brief user hook called when sampled value has changed
+ */
+bool potentiometer_update_user(uint8_t index, uint16_t value);
+
+/** \brief keyboard hook called when sampled value has changed
+ */
+bool potentiometer_update_kb(uint8_t index, uint16_t value);
+
+/** \brief Handle various subsystem background tasks
+ */
+bool potentiometer_task(void);

quantum/quantum.h

@@ -207,6 +207,10 @@ extern layer_state_t layer_state;
 #    include "encoder.h"
 #endif
 
+#ifdef POTENTIOMETER_ENABLE
+#    include "potentiometer.h"
+#endif
+
 #ifdef POINTING_DEVICE_ENABLE
 #    include "pointing_device.h"
 #endif