refactor: Promote debounce to exposed mod lib.

* Promote previously local debounce code from kscan drivers to exposed
  module lib, for use with other drivers as needed.
* Refactor existing kscan driver to new "public" API.

app/module/CMakeLists.txt

@@ -1,3 +1,4 @@
 zephyr_include_directories(include)
 
-add_subdirectory(drivers)
+add_subdirectory(drivers)
+add_subdirectory(lib)

app/module/Kconfig

@@ -1,2 +1,3 @@
 
-rsource "drivers/Kconfig"
+rsource "drivers/Kconfig"
+rsource "lib/Kconfig"

app/module/drivers/kscan/CMakeLists.txt

@@ -3,7 +3,6 @@
 
 zephyr_library_amend()
 
-zephyr_library_sources_ifdef(CONFIG_ZMK_KSCAN_GPIO_DRIVER debounce.c)
 zephyr_library_sources_ifdef(CONFIG_ZMK_KSCAN_GPIO_DRIVER kscan_gpio.c)
 zephyr_library_sources_ifdef(CONFIG_ZMK_KSCAN_GPIO_MATRIX kscan_gpio_matrix.c)
 zephyr_library_sources_ifdef(CONFIG_ZMK_KSCAN_GPIO_DIRECT kscan_gpio_direct.c)

app/module/drivers/kscan/Kconfig

@@ -16,6 +16,7 @@ config ZMK_KSCAN_COMPOSITE_DRIVER
 config ZMK_KSCAN_GPIO_DRIVER
     bool
     select GPIO
+    select ZMK_DEBOUNCE
 
 config ZMK_KSCAN_GPIO_DEMUX
     bool

app/module/drivers/kscan/kscan_gpio_direct.c

@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include "debounce.h"
 #include "kscan_gpio.h"
 
 #include <zephyr/device.h>
@@ -15,6 +14,8 @@
 #include <zephyr/logging/log.h>
 #include <zephyr/sys/util.h>
 
+#include <zmk/debounce.h>
+
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #define DT_DRV_COMPAT zmk_kscan_gpio_direct
@@ -61,11 +62,11 @@ struct kscan_direct_data {
     /** Timestamp of the current or scheduled scan. */
     int64_t scan_time;
     /** Current state of the inputs as an array of length config->inputs.len */
-    struct debounce_state *pin_state;
+    struct zmk_debounce_state *pin_state;
 };
 
 struct kscan_direct_config {
-    struct debounce_config debounce_config;
+    struct zmk_debounce_config debounce_config;
     int32_t debounce_scan_period_ms;
     int32_t poll_period_ms;
     bool toggle_mode;
@@ -182,19 +183,19 @@ static int kscan_direct_read(const struct device *dev) {
             return active;
         }
 
-        debounce_update(&data->pin_state[gpio->index], active, config->debounce_scan_period_ms,
-                        &config->debounce_config);
+        zmk_debounce_update(&data->pin_state[gpio->index], active, config->debounce_scan_period_ms,
+                            &config->debounce_config);
     }
 
     // Process the new state.
     bool continue_scan = false;
 
     for (int i = 0; i < data->inputs.len; i++) {
         const struct kscan_gpio *gpio = &data->inputs.gpios[i];
-        struct debounce_state *state = &data->pin_state[gpio->index];
+        struct zmk_debounce_state *state = &data->pin_state[gpio->index];
 
-        if (debounce_get_changed(state)) {
-            const bool pressed = debounce_is_pressed(state);
+        if (zmk_debounce_get_changed(state)) {
+            const bool pressed = zmk_debounce_is_pressed(state);
 
             LOG_DBG("Sending event at 0,%i state %s", gpio->index, pressed ? "on" : "off");
             data->callback(dev, 0, gpio->index, pressed);
@@ -203,7 +204,7 @@ static int kscan_direct_read(const struct device *dev) {
             }
         }
 
-        continue_scan = continue_scan || debounce_is_active(state);
+        continue_scan = continue_scan || zmk_debounce_is_active(state);
     }
 
     if (continue_scan) {
@@ -332,7 +333,7 @@ static const struct kscan_driver_api kscan_direct_api = {
     static struct kscan_gpio kscan_direct_inputs_##n[] = {                                         \
         LISTIFY(INST_INPUTS_LEN(n), KSCAN_DIRECT_INPUT_CFG_INIT, (, ), n)};                        \
                                                                                                    \
-    static struct debounce_state kscan_direct_state_##n[INST_INPUTS_LEN(n)];                       \
+    static struct zmk_debounce_state kscan_direct_state_##n[INST_INPUTS_LEN(n)];                   \
                                                                                                    \
     COND_INTERRUPTS(                                                                               \
         (static struct kscan_direct_irq_callback kscan_direct_irqs_##n[INST_INPUTS_LEN(n)];))      \

app/module/drivers/kscan/kscan_gpio_matrix.c

@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include "debounce.h"
 #include "kscan_gpio.h"
 
 #include <zephyr/device.h>
@@ -16,6 +15,8 @@
 #include <zephyr/sys/__assert.h>
 #include <zephyr/sys/util.h>
 
+#include <zmk/debounce.h>
+
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #define DT_DRV_COMPAT zmk_kscan_gpio_matrix
@@ -80,12 +81,12 @@ struct kscan_matrix_data {
      * Current state of the matrix as a flattened 2D array of length
      * (config->rows * config->cols)
      */
-    struct debounce_state *matrix_state;
+    struct zmk_debounce_state *matrix_state;
 };
 
 struct kscan_matrix_config {
     struct kscan_gpio_list outputs;
-    struct debounce_config debounce_config;
+    struct zmk_debounce_config debounce_config;
     size_t rows;
     size_t cols;
     int32_t debounce_scan_period_ms;
@@ -242,8 +243,8 @@ static int kscan_matrix_read(const struct device *dev) {
                 return active;
             }
 
-            debounce_update(&data->matrix_state[index], active, config->debounce_scan_period_ms,
-                            &config->debounce_config);
+            zmk_debounce_update(&data->matrix_state[index], active, config->debounce_scan_period_ms,
+                                &config->debounce_config);
         }
 
         err = gpio_pin_set_dt(&out_gpio->spec, 0);
@@ -263,16 +264,16 @@ static int kscan_matrix_read(const struct device *dev) {
     for (int r = 0; r < config->rows; r++) {
         for (int c = 0; c < config->cols; c++) {
             const int index = state_index_rc(config, r, c);
-            struct debounce_state *state = &data->matrix_state[index];
+            struct zmk_debounce_state *state = &data->matrix_state[index];
 
-            if (debounce_get_changed(state)) {
-                const bool pressed = debounce_is_pressed(state);
+            if (zmk_debounce_get_changed(state)) {
+                const bool pressed = zmk_debounce_is_pressed(state);
 
                 LOG_DBG("Sending event at %i,%i state %s", r, c, pressed ? "on" : "off");
                 data->callback(dev, r, c, pressed);
             }
 
-            continue_scan = continue_scan || debounce_is_active(state);
+            continue_scan = continue_scan || zmk_debounce_is_active(state);
         }
     }
 
@@ -438,7 +439,7 @@ static const struct kscan_driver_api kscan_matrix_api = {
     static struct kscan_gpio kscan_matrix_cols_##n[] = {                                           \
         LISTIFY(INST_COLS_LEN(n), KSCAN_GPIO_COL_CFG_INIT, (, ), n)};                              \
                                                                                                    \
-    static struct debounce_state kscan_matrix_state_##n[INST_MATRIX_LEN(n)];                       \
+    static struct zmk_debounce_state kscan_matrix_state_##n[INST_MATRIX_LEN(n)];                   \
                                                                                                    \
     COND_INTERRUPTS(                                                                               \
         (static struct kscan_matrix_irq_callback kscan_matrix_irqs_##n[INST_INPUTS_LEN(n)];))      \

app/module/drivers/kscan/debounce.h → app/module/include/zmk/debounce.h

@@ -13,13 +13,13 @@
 #define DEBOUNCE_COUNTER_BITS 14
 #define DEBOUNCE_COUNTER_MAX BIT_MASK(DEBOUNCE_COUNTER_BITS)
 
-struct debounce_state {
+struct zmk_debounce_state {
     bool pressed : 1;
     bool changed : 1;
     uint16_t counter : DEBOUNCE_COUNTER_BITS;
 };
 
-struct debounce_config {
+struct zmk_debounce_config {
     /** Duration a switch must be pressed to latch as pressed. */
     uint32_t debounce_press_ms;
     /** Duration a switch must be released to latch as released. */
@@ -34,23 +34,23 @@ struct debounce_config {
  * @param elapsed_ms Time elapsed since the previous update in milliseconds.
  * @param config Debounce settings.
  */
-void debounce_update(struct debounce_state *state, const bool active, const int elapsed_ms,
-                     const struct debounce_config *config);
+void zmk_debounce_update(struct zmk_debounce_state *state, const bool active, const int elapsed_ms,
+                         const struct zmk_debounce_config *config);
 
 /**
  * @returns whether the switch is either latched as pressed or it is potentially
  * pressed but the debouncer has not yet made a decision. If this returns true,
  * the kscan driver should continue to poll quickly.
  */
-bool debounce_is_active(const struct debounce_state *state);
+bool zmk_debounce_is_active(const struct zmk_debounce_state *state);
 
 /**
  * @returns whether the switch is latched as pressed.
  */
-bool debounce_is_pressed(const struct debounce_state *state);
+bool zmk_debounce_is_pressed(const struct zmk_debounce_state *state);
 
 /**
  * @returns whether the pressed state of the switch changed in the last call to
  * debounce_update.
  */
-bool debounce_get_changed(const struct debounce_state *state);
+bool zmk_debounce_get_changed(const struct zmk_debounce_state *state);

app/module/lib/CMakeLists.txt

@@ -0,0 +1,2 @@
+
+add_subdirectory_ifdef(CONFIG_ZMK_DEBOUNCE zmk_debounce)

app/module/lib/Kconfig

@@ -0,0 +1,2 @@
+
+rsource "zmk_debounce/Kconfig"

app/module/lib/zmk_debounce/CMakeLists.txt

@@ -0,0 +1,3 @@
+
+zephyr_library()
+zephyr_library_sources(debounce.c)

app/module/lib/zmk_debounce/Kconfig

@@ -0,0 +1,3 @@
+
+config ZMK_DEBOUNCE
+    bool "Debounce Support"

app/module/drivers/kscan/debounce.c → app/module/lib/zmk_debounce/debounce.c

@@ -4,31 +4,31 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include "debounce.h"
+#include <zmk/debounce.h>
 
-static uint32_t get_threshold(const struct debounce_state *state,
-                              const struct debounce_config *config) {
+static uint32_t get_threshold(const struct zmk_debounce_state *state,
+                              const struct zmk_debounce_config *config) {
     return state->pressed ? config->debounce_release_ms : config->debounce_press_ms;
 }
 
-static void increment_counter(struct debounce_state *state, const int elapsed_ms) {
+static void increment_counter(struct zmk_debounce_state *state, const int elapsed_ms) {
     if (state->counter + elapsed_ms > DEBOUNCE_COUNTER_MAX) {
         state->counter = DEBOUNCE_COUNTER_MAX;
     } else {
         state->counter += elapsed_ms;
     }
 }
 
-static void decrement_counter(struct debounce_state *state, const int elapsed_ms) {
+static void decrement_counter(struct zmk_debounce_state *state, const int elapsed_ms) {
     if (state->counter < elapsed_ms) {
         state->counter = 0;
     } else {
         state->counter -= elapsed_ms;
     }
 }
 
-void debounce_update(struct debounce_state *state, const bool active, const int elapsed_ms,
-                     const struct debounce_config *config) {
+void zmk_debounce_update(struct zmk_debounce_state *state, const bool active, const int elapsed_ms,
+                         const struct zmk_debounce_config *config) {
     // This uses a variation of the integrator debouncing described at
     // https://www.kennethkuhn.com/electronics/debounce.c
     // Every update where "active" does not match the current state, we increment
@@ -53,10 +53,10 @@ void debounce_update(struct debounce_state *state, const bool active, const int
     state->changed = true;
 }
 
-bool debounce_is_active(const struct debounce_state *state) {
+bool zmk_debounce_is_active(const struct zmk_debounce_state *state) {
     return state->pressed || state->counter > 0;
 }
 
-bool debounce_is_pressed(const struct debounce_state *state) { return state->pressed; }
+bool zmk_debounce_is_pressed(const struct zmk_debounce_state *state) { return state->pressed; }
 
-bool debounce_get_changed(const struct debounce_state *state) { return state->changed; }
+bool zmk_debounce_get_changed(const struct zmk_debounce_state *state) { return state->changed; }