modules: button: Add support for long press detection

Add capability to distinguish between short and long button press.

Signed-off-by: Jan Tore Guggedal <jantore.guggedal@nordicsemi.no>

Author: jtguggedal

app/src/modules/button/Kconfig.button

@@ -12,6 +12,14 @@ config APP_BUTTON_SHELL
 	help
 	  Enable shell for the button module.
 
+config APP_BUTTON_LONG_PRESS_TIMEOUT_MS
+	int "Long press timeout in milliseconds"
+	default 3000
+	help
+	  Time in milliseconds that a button must be held to be considered
+	  a long press. Short presses are detected when the button is
+	  released before this timeout expires.
+
 module = APP_BUTTON
 module-str = Button
 source "subsys/logging/Kconfig.template.log_config"

app/src/modules/button/button.c

@@ -16,39 +16,104 @@
 /* Register log module */
 LOG_MODULE_REGISTER(button, CONFIG_APP_BUTTON_LOG_LEVEL);
 
+/* Long press timeout in milliseconds */
+#define LONG_PRESS_TIMEOUT_MS CONFIG_APP_BUTTON_LONG_PRESS_TIMEOUT_MS
+
+/* Button state structure */
+static struct {
+	uint32_t pressed_buttons;
+	struct k_work_delayable long_press_work;
+} button_state;
+
 /* Define channels provided by this module */
 ZBUS_CHAN_DEFINE(BUTTON_CHAN,
-		 uint8_t,
+		 struct button_msg,
 		 NULL,
 		 NULL,
 		 ZBUS_OBSERVERS_EMPTY,
 		 ZBUS_MSG_INIT(0)
 );
 
-/* Button handler called when a user pushes a button */
-static void button_handler(uint32_t button_states, uint32_t has_changed)
+/* Work handler for long press detection */
+static void long_press_work_handler(struct k_work *work)
 {
 	int err;
-	uint8_t button_number = 1;
+	struct button_msg msg;
 
-	if (has_changed & button_states & DK_BTN1_MSK) {
-		LOG_DBG("Button 1 pressed!");
+	ARG_UNUSED(work);
 
-		err = zbus_chan_pub(&BUTTON_CHAN, &button_number, K_SECONDS(1));
+	/* Check if button is still pressed */
+	if (button_state.pressed_buttons & DK_BTN1_MSK) {
+		LOG_DBG("Button 1 long press detected!");
+
+		msg.button_number = 1;
+		msg.type = BUTTON_PRESS_LONG;
+
+		err = zbus_chan_pub(&BUTTON_CHAN, &msg, K_SECONDS(1));
 		if (err) {
-			LOG_ERR("zbus_chan_pub, error: %d", err);
+			LOG_ERR("zbus_chan_pub long press, error: %d", err);
 			SEND_FATAL_ERROR();
-			return;
+		}
+	}
+}
+
+/* Publish short press message */
+static void publish_short_press(uint8_t button_number)
+{
+	int err;
+	struct button_msg msg;
+
+	msg.button_number = button_number;
+	msg.type = BUTTON_PRESS_SHORT;
+
+	LOG_DBG("Button %d short press", button_number);
+
+	err = zbus_chan_pub(&BUTTON_CHAN, &msg, K_SECONDS(1));
+	if (err) {
+		LOG_ERR("zbus_chan_pub short press, error: %d", err);
+		SEND_FATAL_ERROR();
+	}
+}
+
+/* Button handler called when a user pushes a button */
+static void button_handler(uint32_t button_states, uint32_t has_changed)
+{
+	/* Handle button 1 press */
+	if (!(has_changed & DK_BTN1_MSK)) {
+		return;
+	}
+
+	if (button_states & DK_BTN1_MSK) {
+		button_state.pressed_buttons |= DK_BTN1_MSK;
+
+		/* Start long press timer */
+		k_work_schedule(&button_state.long_press_work, K_MSEC(LONG_PRESS_TIMEOUT_MS));
+	} else {
+		button_state.pressed_buttons &= ~DK_BTN1_MSK;
+
+		/* Cancel long press timer if it was running and send short press */
+		if (k_work_delayable_is_pending(&button_state.long_press_work)) {
+			(void)k_work_cancel_delayable(&button_state.long_press_work);
+
+			/* Timer was running, this is a short press */
+			publish_short_press(1);
 		}
 	}
 }
 
 static int button_init(void)
 {
+	int err;
+
 	LOG_DBG("button_init");
 
-	int err = dk_buttons_init(button_handler);
+	/* Initialize button state */
+	button_state.pressed_buttons = 0;
+
+	k_work_init_delayable(&button_state.long_press_work,
+			      long_press_work_handler);
 
+	err = dk_buttons_init(button_handler);
 	if (err) {
 		LOG_ERR("dk_buttons_init, error: %d", err);
 		SEND_FATAL_ERROR();

app/src/modules/button/button.h

@@ -14,6 +14,26 @@
 extern "C" {
 #endif
 
+/** @brief Button message types */
+enum button_msg_type {
+	/* Output message types */
+
+	/** Short button press detected */
+	BUTTON_PRESS_SHORT = 0x1,
+
+	/** Long button press detected */
+	BUTTON_PRESS_LONG,
+};
+
+/** @brief Button message data structure */
+struct button_msg {
+	enum button_msg_type type;
+	uint8_t button_number;
+};
+
+/** @brief Cast a pointer to a message to a button message */
+#define MSG_TO_BUTTON_MSG(_msg)	(*(const struct button_msg *)_msg)
+
 /* Channels provided by this module */
 ZBUS_CHAN_DECLARE(
 	BUTTON_CHAN

app/src/modules/button/button_shell.c

@@ -17,6 +17,9 @@ static int cmd_button_press(const struct shell *sh, size_t argc, char **argv)
 {
 	int err;
 	uint8_t button_number;
+	struct button_msg msg = {
+		.type = BUTTON_PRESS_SHORT
+	};
 
 	if (argc != 2) {
 		(void)shell_print(sh, "Invalid number of arguments (%d)", argc);
@@ -31,9 +34,9 @@ static int cmd_button_press(const struct shell *sh, size_t argc, char **argv)
 		return 1;
 	}
 
-	LOG_DBG("Button %d pressed", button_number);
+	msg.button_number = button_number;
 
-	err = zbus_chan_pub(&BUTTON_CHAN, &button_number, K_SECONDS(1));
+	err = zbus_chan_pub(&BUTTON_CHAN, &msg, K_SECONDS(1));
 	if (err) {
 		(void)shell_print(sh, "zbus_chan_pub, error: %d", err);
 		return 1;

tests/module/button/CMakeLists.txt

@@ -9,11 +9,11 @@ cmake_minimum_required(VERSION 3.20.0)
 find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(environmental_module_test)
 
-test_runner_generate(src/main.c)
+test_runner_generate(src/button_module_test.c)
 
 target_sources(app
   PRIVATE
-  src/main.c
+  src/button_module_test.c
   ../../../app/src/modules/button/button.c
 )
 
@@ -27,5 +27,6 @@ target_link_options(app PRIVATE --whole-archive)
 # Options that cannot be passed through Kconfig fragments
 target_compile_definitions(app PRIVATE
 	-DCONFIG_APP_CLOUD_PAYLOAD_BUFFER_MAX_SIZE=100
-  -DCONFIG_APP_BUTTON_LOG_LEVEL=4
+  -DCONFIG_APP_BUTTON_LOG_LEVEL=0
+  -DCONFIG_APP_BUTTON_LONG_PRESS_TIMEOUT_MS=3000
 )

tests/module/button/prj.conf

@@ -19,3 +19,5 @@ CONFIG_HEAP_MEM_POOL_SIZE=40000
 CONFIG_SMF=y
 CONFIG_SMF_ANCESTOR_SUPPORT=y
 CONFIG_SMF_INITIAL_TRANSITION=y
+
+CONFIG_NATIVE_SIM_SLOWDOWN_TO_REAL_TIME=n