Tri-state behavior

app/CMakeLists.txt

@@ -50,6 +50,7 @@ if ((NOT CONFIG_ZMK_SPLIT) OR CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
   target_sources(app PRIVATE src/behaviors/behavior_toggle_layer.c)
   target_sources(app PRIVATE src/behaviors/behavior_to_layer.c)
   target_sources(app PRIVATE src/behaviors/behavior_transparent.c)
+  target_sources_ifdef(CONFIG_ZMK_BEHAVIOR_TRI_STATE app PRIVATE src/behaviors/behavior_tri_state.c)
   target_sources(app PRIVATE src/behaviors/behavior_none.c)
   target_sources_ifdef(CONFIG_ZMK_BEHAVIOR_SENSOR_ROTATE app PRIVATE src/behaviors/behavior_sensor_rotate.c)
   target_sources_ifdef(CONFIG_ZMK_BEHAVIOR_SENSOR_ROTATE_VAR app PRIVATE src/behaviors/behavior_sensor_rotate_var.c)

app/Kconfig

@@ -365,6 +365,12 @@ config ZMK_MACRO_DEFAULT_TAP_MS
     int "Default time to wait (in milliseconds) between the press and release events of a tapped behavior in macros"
     default 30
 
+DT_COMPAT_ZMK_BEHAVIOR_TRI_STATE := zmk,behavior-tri-state
+
+config ZMK_BEHAVIOR_TRI_STATE
+        bool
+        default $(dt_compat_enabled,$(DT_COMPAT_ZMK_BEHAVIOR_TRI_STATE))
+
 endmenu
 
 menu "Advanced"

app/dts/bindings/behaviors/zmk,behavior-tri-state.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2022 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: Tri-State Behavior
+
+compatible: "zmk,behavior-tri-state"
+
+include: zero_param.yaml
+
+properties:
+  bindings:
+    type: phandle-array
+    required: true
+  ignored-key-positions:
+    type: array
+    required: false
+    default: []
+  ignored-layers:
+    type: array
+    required: false
+    default: []
+  timeout-ms:
+    type: int
+    default: -1
+  tap-ms:
+    type: int
+    default: 5

app/src/behaviors/behavior_tri_state.c

@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 2022 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT zmk_behavior_tri_state
+
+#include <zephyr/device.h>
+#include <drivers/behavior.h>
+#include <zephyr/logging/log.h>
+#include <zmk/behavior.h>
+#include <zmk/behavior_queue.h>
+#include <zmk/keymap.h>
+#include <zmk/matrix.h>
+#include <zmk/event_manager.h>
+#include <zmk/events/position_state_changed.h>
+#include <zmk/events/layer_state_changed.h>
+#include <zmk/hid.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#define ZMK_BHV_MAX_ACTIVE_TRI_STATES 10
+
+struct behavior_tri_state_config {
+    int32_t ignored_key_positions_len;
+    int32_t ignored_layers_len;
+    struct zmk_behavior_binding start_behavior;
+    struct zmk_behavior_binding continue_behavior;
+    struct zmk_behavior_binding end_behavior;
+    int32_t ignored_layers;
+    int32_t timeout_ms;
+    int tap_ms;
+    uint8_t ignored_key_positions[];
+};
+
+struct active_tri_state {
+    bool is_active;
+    bool is_pressed;
+    bool first_press;
+    uint32_t position;
+    const struct behavior_tri_state_config *config;
+    struct k_work_delayable release_timer;
+    int64_t release_at;
+    bool timer_started;
+    bool timer_cancelled;
+};
+
+static int stop_timer(struct active_tri_state *tri_state) {
+    int timer_cancel_result = k_work_cancel_delayable(&tri_state->release_timer);
+    if (timer_cancel_result == -EINPROGRESS) {
+        // too late to cancel, we'll let the timer handler clear up.
+        tri_state->timer_cancelled = true;
+    }
+    return timer_cancel_result;
+}
+
+static void reset_timer(int32_t timestamp, struct active_tri_state *tri_state) {
+    tri_state->release_at = timestamp + tri_state->config->timeout_ms;
+    int32_t ms_left = tri_state->release_at - k_uptime_get();
+    if (ms_left > 0) {
+        k_work_schedule(&tri_state->release_timer, K_MSEC(ms_left));
+        LOG_DBG("Successfully reset tri-state timer");
+    }
+}
+
+void trigger_end_behavior(struct active_tri_state *si) {
+    zmk_behavior_queue_add(si->position, si->config->end_behavior, true, si->config->tap_ms);
+    zmk_behavior_queue_add(si->position, si->config->end_behavior, false, 0);
+}
+
+void behavior_tri_state_timer_handler(struct k_work *item) {
+    struct active_tri_state *tri_state = CONTAINER_OF(item, struct active_tri_state, release_timer);
+    if (!tri_state->is_active || tri_state->timer_cancelled || tri_state->is_pressed) {
+        return;
+    }
+    LOG_DBG("Tri-state deactivated due to timer");
+    tri_state->is_active = false;
+    trigger_end_behavior(tri_state);
+}
+
+static void clear_tri_state(struct active_tri_state *tri_state) { tri_state->is_active = false; }
+
+struct active_tri_state active_tri_states[ZMK_BHV_MAX_ACTIVE_TRI_STATES] = {};
+
+static struct active_tri_state *find_tri_state(uint32_t position) {
+    for (int i = 0; i < ZMK_BHV_MAX_ACTIVE_TRI_STATES; i++) {
+        if (active_tri_states[i].position == position && active_tri_states[i].is_active) {
+            return &active_tri_states[i];
+        }
+    }
+    return NULL;
+}
+
+static int new_tri_state(uint32_t position, const struct behavior_tri_state_config *config,
+                         struct active_tri_state **tri_state) {
+    for (int i = 0; i < ZMK_BHV_MAX_ACTIVE_TRI_STATES; i++) {
+        struct active_tri_state *const ref_tri_state = &active_tri_states[i];
+        if (!ref_tri_state->is_active) {
+            ref_tri_state->position = position;
+            ref_tri_state->config = config;
+            ref_tri_state->is_active = true;
+            ref_tri_state->is_pressed = false;
+            ref_tri_state->first_press = true;
+            *tri_state = ref_tri_state;
+            return 0;
+        }
+    }
+    return -ENOMEM;
+}
+
+static bool is_other_key_ignored(struct active_tri_state *tri_state, int32_t position) {
+    for (int i = 0; i < tri_state->config->ignored_key_positions_len; i++) {
+        if (tri_state->config->ignored_key_positions[i] == position) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool is_layer_ignored(struct active_tri_state *tri_state, int32_t layer) {
+    if ((BIT(layer) & tri_state->config->ignored_layers) != 0U) {
+        return true;
+    }
+    return false;
+}
+
+static int on_tri_state_binding_pressed(struct zmk_behavior_binding *binding,
+                                        struct zmk_behavior_binding_event event) {
+    const struct device *dev = device_get_binding(binding->behavior_dev);
+    const struct behavior_tri_state_config *cfg = dev->config;
+    struct active_tri_state *tri_state;
+    tri_state = find_tri_state(event.position);
+    if (tri_state == NULL) {
+        if (new_tri_state(event.position, cfg, &tri_state) == -ENOMEM) {
+            LOG_ERR("Unable to create new tri_state. Insufficient space in "
+                    "active_tri_states[].");
+            return ZMK_BEHAVIOR_OPAQUE;
+        }
+        LOG_DBG("%d created new tri_state", event.position);
+    }
+    LOG_DBG("%d tri_state pressed", event.position);
+    tri_state->is_pressed = true;
+    if (tri_state->first_press) {
+        behavior_keymap_binding_pressed((struct zmk_behavior_binding *)&cfg->start_behavior, event);
+        behavior_keymap_binding_released((struct zmk_behavior_binding *)&cfg->start_behavior,
+                                         event);
+        tri_state->first_press = false;
+    }
+    behavior_keymap_binding_pressed((struct zmk_behavior_binding *)&cfg->continue_behavior, event);
+    return ZMK_BEHAVIOR_OPAQUE;
+}
+
+static void release_tri_state(struct zmk_behavior_binding_event event,
+                              struct zmk_behavior_binding *continue_behavior) {
+    struct active_tri_state *tri_state = find_tri_state(event.position);
+    if (tri_state == NULL) {
+        return;
+    }
+    tri_state->is_pressed = false;
+    behavior_keymap_binding_released(continue_behavior, event);
+    reset_timer(k_uptime_get(), tri_state);
+}
+
+static int on_tri_state_binding_released(struct zmk_behavior_binding *binding,
+                                         struct zmk_behavior_binding_event event) {
+    const struct device *dev = device_get_binding(binding->behavior_dev);
+    const struct behavior_tri_state_config *cfg = dev->config;
+    LOG_DBG("%d tri_state keybind released", event.position);
+    release_tri_state(event, (struct zmk_behavior_binding *)&cfg->continue_behavior);
+    return ZMK_BEHAVIOR_OPAQUE;
+}
+
+static int behavior_tri_state_init(const struct device *dev) {
+    static bool init_first_run = true;
+    if (init_first_run) {
+        for (int i = 0; i < ZMK_BHV_MAX_ACTIVE_TRI_STATES; i++) {
+            k_work_init_delayable(&active_tri_states[i].release_timer,
+                                  behavior_tri_state_timer_handler);
+            clear_tri_state(&active_tri_states[i]);
+        }
+    }
+    init_first_run = false;
+    return 0;
+}
+
+static const struct behavior_driver_api behavior_tri_state_driver_api = {
+    .binding_pressed = on_tri_state_binding_pressed,
+    .binding_released = on_tri_state_binding_released,
+};
+
+static int tri_state_listener(const zmk_event_t *eh);
+static int tri_state_position_state_changed_listener(const zmk_event_t *eh);
+static int tri_state_layer_state_changed_listener(const zmk_event_t *eh);
+
+ZMK_LISTENER(behavior_tri_state, tri_state_listener);
+ZMK_SUBSCRIPTION(behavior_tri_state, zmk_position_state_changed);
+ZMK_SUBSCRIPTION(behavior_tri_state, zmk_layer_state_changed);
+
+static int tri_state_listener(const zmk_event_t *eh) {
+    if (as_zmk_position_state_changed(eh) != NULL) {
+        return tri_state_position_state_changed_listener(eh);
+    } else if (as_zmk_layer_state_changed(eh) != NULL) {
+        return tri_state_layer_state_changed_listener(eh);
+    }
+    return ZMK_EV_EVENT_BUBBLE;
+}
+
+static int tri_state_position_state_changed_listener(const zmk_event_t *eh) {
+    struct zmk_position_state_changed *ev = as_zmk_position_state_changed(eh);
+    if (ev == NULL) {
+        return ZMK_EV_EVENT_BUBBLE;
+    }
+    for (int i = 0; i < ZMK_BHV_MAX_ACTIVE_TRI_STATES; i++) {
+        struct active_tri_state *tri_state = &active_tri_states[i];
+        if (!tri_state->is_active) {
+            continue;
+        }
+        if (tri_state->position == ev->position) {
+            continue;
+        }
+        if (!is_other_key_ignored(tri_state, ev->position)) {
+            LOG_DBG("Tri-State interrupted, ending at %d %d", tri_state->position, ev->position);
+            tri_state->is_active = false;
+            struct zmk_behavior_binding_event event = {.position = tri_state->position,
+                                                       .timestamp = k_uptime_get()};
+            if (tri_state->is_pressed) {
+                behavior_keymap_binding_released(
+                    (struct zmk_behavior_binding *)&tri_state->config->continue_behavior, event);
+            }
+            trigger_end_behavior(tri_state);
+            return ZMK_EV_EVENT_BUBBLE;
+        }
+        if (ev->state) {
+            stop_timer(tri_state);
+        } else {
+            reset_timer(ev->timestamp, tri_state);
+        }
+    }
+    return ZMK_EV_EVENT_BUBBLE;
+}
+
+static int tri_state_layer_state_changed_listener(const zmk_event_t *eh) {
+    struct zmk_layer_state_changed *ev = as_zmk_layer_state_changed(eh);
+    if (ev == NULL) {
+        return ZMK_EV_EVENT_BUBBLE;
+    }
+    if (!ev->state) {
+        return ZMK_EV_EVENT_BUBBLE;
+    }
+    for (int i = 0; i < ZMK_BHV_MAX_ACTIVE_TRI_STATES; i++) {
+        struct active_tri_state *tri_state = &active_tri_states[i];
+        if (!tri_state->is_active) {
+            continue;
+        }
+        if (!is_layer_ignored(tri_state, ev->layer)) {
+            LOG_DBG("Tri-State layer changed, ending at %d %d", tri_state->position, ev->layer);
+            tri_state->is_active = false;
+            struct zmk_behavior_binding_event event = {.position = tri_state->position,
+                                                       .timestamp = k_uptime_get()};
+            if (tri_state->is_pressed) {
+                behavior_keymap_binding_released(
+                    (struct zmk_behavior_binding *)&tri_state->config->continue_behavior, event);
+            }
+            behavior_keymap_binding_pressed(
+                (struct zmk_behavior_binding *)&tri_state->config->end_behavior, event);
+            behavior_keymap_binding_released(
+                (struct zmk_behavior_binding *)&tri_state->config->end_behavior, event);
+            return ZMK_EV_EVENT_BUBBLE;
+        }
+    }
+    return ZMK_EV_EVENT_BUBBLE;
+}
+
+#define _TRANSFORM_ENTRY(idx, node)                                                                \
+    {                                                                                              \
+        .behavior_dev = DT_LABEL(DT_INST_PHANDLE_BY_IDX(node, bindings, idx)),                     \
+        .param1 = COND_CODE_0(DT_INST_PHA_HAS_CELL_AT_IDX(node, bindings, idx, param1), (0),       \
+                              (DT_INST_PHA_BY_IDX(node, bindings, idx, param1))),                  \
+        .param2 = COND_CODE_0(DT_INST_PHA_HAS_CELL_AT_IDX(node, bindings, idx, param2), (0),       \
+                              (DT_INST_PHA_BY_IDX(node, bindings, idx, param2))),                  \
+    }
+
+#define IF_BIT(n, prop, i) BIT(DT_PROP_BY_IDX(n, prop, i)) |
+
+#define TRI_STATE_INST(n)                                                                          \
+    static struct behavior_tri_state_config behavior_tri_state_config_##n = {                      \
+        .ignored_key_positions = DT_INST_PROP(n, ignored_key_positions),                           \
+        .ignored_key_positions_len = DT_INST_PROP_LEN(n, ignored_key_positions),                   \
+        .ignored_layers = DT_INST_FOREACH_PROP_ELEM(n, ignored_layers, IF_BIT) 0,                  \
+        .ignored_layers_len = DT_INST_PROP_LEN(n, ignored_layers),                                 \
+        .timeout_ms = DT_INST_PROP(n, timeout_ms),                                                 \
+        .tap_ms = DT_INST_PROP(n, tap_ms),                                                         \
+        .start_behavior = _TRANSFORM_ENTRY(0, n),                                                  \
+        .continue_behavior = _TRANSFORM_ENTRY(1, n),                                               \
+        .end_behavior = _TRANSFORM_ENTRY(2, n)};                                                   \
+    DEVICE_DT_INST_DEFINE(n, behavior_tri_state_init, NULL, NULL, &behavior_tri_state_config_##n,  \
+                          APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT,                        \
+                          &behavior_tri_state_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(TRI_STATE_INST)

app/tests/tri-state/behavior_keymap.dtsi

@@ -0,0 +1,40 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan_mock.h>
+
+/ {
+    behaviors {
+        swap: swap {
+            compatible = "zmk,behavior-tri-state";
+            label = "SWAPPER";
+            #binding-cells = <0>;
+            bindings = <&kt LALT>, <&kp TAB>, <&kt LALT>;
+            ignored-key-positions = <2 3>;
+            ignored-layers = <1>;
+            timeout-ms = <200>;
+        };
+    };
+
+    keymap {
+        compatible = "zmk,keymap";
+        label ="Default keymap";
+
+        default_layer {
+            bindings = <
+                &swap    &kp A
+                &kp B    &tog 1>;
+        };
+
+        extra_layer {
+            bindings = <
+                &kp A     &kp B
+                &tog 2    &trans>;
+        };
+
+        extra_layer2 {
+            bindings = <
+                &kp N1    &kp N2
+                &trans     &kp N3>;
+        };
+    };
+};

app/tests/tri-state/swapper-int-shared-key/events.patterns

@@ -0,0 +1,2 @@
+s/.*hid_listener_keycode/kp/p
+s/.*on_tri_state_binding/tri_state_binding/p