Implements button handling

- DTS bindings
- Debouncing logic
- New `input` for testing and interrupt power profiling

code/nrf-connect/prstlib/CMakeLists.txt

@@ -11,4 +11,4 @@ add_library(prstlib STATIC
 )
 
 target_include_directories(prstlib PRIVATE include)
-target_link_libraries(prstlib PUBLIC zephyr_interface)
+target_link_libraries(prstlib PUBLIC zephyr_interface kernel)

code/nrf-connect/prstlib/boards/arm/bparasite_nrf52833/bparasite_nrf52833.dts

@@ -28,9 +28,9 @@
 	buttons {
 		compatible = "gpio-keys";
 		button0: button_0 {
-			// P0.12.
+			// P0.30.
-			gpios = <&gpio0 12 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+			gpios = <&gpio0 30 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
-			label = "Push button switch 0";
+			label = "Push button SW1";
 		};
 	};
 
@@ -62,6 +62,9 @@
 
 &gpio0 {
 	status = "okay";
+	// For low-power EDGE interrupts.
+	// See github.com/zephyrproject-rtos/zephyr/issues/28499.
+	sense-edge-mask = <0xffffffff>;
 };
 
 &gpio1 {

code/nrf-connect/prstlib/boards/arm/bparasite_nrf52840/bparasite_nrf52840.dts

@@ -28,9 +28,9 @@
 	buttons {
 		compatible = "gpio-keys";
 		button0: button_0 {
-			// P0.12.
+			// P0.30.
-			gpios = <&gpio0 12 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
+			gpios = <&gpio0 30 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
-			label = "Push button switch 0";
+			label = "Push button SW1";
 		};
 	};
 
@@ -62,6 +62,9 @@
 
 &gpio0 {
 	status = "okay";
+	// For low-power EDGE interrupts.
+	// github.com/zephyrproject-rtos/zephyr/issues/28499
+	sense-edge-mask = <0xffffffff>;
 };
 
 &gpio1 {

code/nrf-connect/prstlib/include/prstlib/button.h

@@ -1,7 +1,24 @@
 #ifndef _PRST_BUTTON_H_
 #define _PRST_BUTTON_H_
 
-// Inits button driver and registers callback.
+#include <stdbool.h>
+
+typedef enum {
+  PRST_BUTTON_SW1 = 0,
+} prst_button_t;
+
+typedef void (*prst_button_callback_t)(prst_button_t button, bool is_active);
+
+// Inits button driver.
 int prst_button_init();
 
+// Configures ISR and calls callback on debounced button press/release.
+int prst_button_register_callback(prst_button_callback_t callback);
+
+// Returns:
+// 1 if button is active
+// 0 if button is inactive
+// -1 on error
+int prst_button_poll(prst_button_t prst_button);
+
 #endif  // _PRST_BUTTON_H_

code/nrf-connect/prstlib/src/button.c

@@ -1,6 +1,7 @@
 #include "prstlib/button.h"
 
 #include <zephyr/drivers/gpio.h>
+#include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
 
 #include "prstlib/led.h"
@@ -8,23 +9,60 @@
 
 LOG_MODULE_REGISTER(button, CONFIG_PRSTLIB_LOG_LEVEL);
 
+static struct k_work_delayable button_pressed_delayable;
+
 static struct gpio_dt_spec button =
     GPIO_DT_SPEC_GET(DT_NODELABEL(button0), gpios);
 
 static struct gpio_callback cb_data;
 
-static void button_pressed(const struct device *dev, struct gpio_callback *cb,
+static prst_button_callback_t user_callback = NULL;
-                           uint32_t pins) {
+
-  LOG_INF("Button pressed");
+static void maybe_call_user_callback(prst_button_t button, bool is_active) {
-  prst_led_toggle();
+  if (user_callback != NULL) {
+    user_callback(button, is_active);
+  } else {
+    LOG_WRN("No user callback registered for button %d", button);
+  }
+}
+
+static void button_pressed_cb(struct k_work *work) {
+  int button_state = prst_button_poll(PRST_BUTTON_SW1);
+  if (button_state < 0) {
+    LOG_ERR("Failed to poll button");
+    return;
+  }
+  return maybe_call_user_callback(PRST_BUTTON_SW1, button_state);
+}
+
+static void button_pressed_isr(const struct device *dev, struct gpio_callback *cb,
+                               uint32_t pins) {
+  k_work_reschedule(&button_pressed_delayable, K_MSEC(10));
 }
 
 int prst_button_init() {
   RET_IF_ERR(!device_is_ready(button.port));
   RET_IF_ERR(gpio_pin_configure_dt(&button, GPIO_INPUT));
-  // EDGE interrupts consume more power! Just use a LEVEL one.
-  RET_IF_ERR(gpio_pin_interrupt_configure_dt(&button, GPIO_INT_LEVEL_ACTIVE));
-  gpio_init_callback(&cb_data, button_pressed, BIT(button.pin));
-  RET_IF_ERR(gpio_add_callback(button.port, &cb_data));
   return 0;
+}
+
+int prst_button_register_callback(prst_button_callback_t callback) {
+  k_work_init_delayable(&button_pressed_delayable, button_pressed_cb);
+  // EDGE interrupts seem to consume more power than LEVEL ones.
+  // For GPIO_INT_EDGE_BOTH: 16 uA idle.
+  // For GPIO_INT_LEVEL_ACTIVE: 3 uA idle.
+  // Related issue:
+  // https://github.com/zephyrproject-rtos/zephyr/issues/28499
+  // Apparently sense-edge-mask brings the power consumption down to
+  // 3 uA for EDGE interrupts too.
+  RET_IF_ERR(gpio_pin_interrupt_configure_dt(&button, GPIO_INT_EDGE_BOTH));
+  gpio_init_callback(&cb_data, button_pressed_isr, BIT(button.pin));
+  RET_IF_ERR(gpio_add_callback(button.port, &cb_data));
+  user_callback = callback;
+  return 0;
+}
+
+int prst_button_poll(prst_button_t prst_button) {
+  RET_CHECK(prst_button == PRST_BUTTON_SW1, "Invalid button");
+  return gpio_pin_get_dt(&button);
 }

code/nrf-connect/samples/ble/prj.conf

@@ -23,4 +23,5 @@ CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
 CONFIG_PRST_BLE_ENCODING_BTHOME_V2=y
 # CONFIG_PRST_SLEEP_DURATION_SEC=1
 
-CONFIG_PRSTLIB_LOG_LEVEL_DBG=y
+# prstlib config - ser all options in prstlib/Kconfig.
+# CONFIG_PRSTLIB_LOG_LEVEL_DBG=y

code/nrf-connect/samples/input/.gitignore

@@ -0,0 +1,2 @@
+build
+build_*

code/nrf-connect/samples/input/CMakeLists.txt

@@ -0,0 +1,15 @@
+cmake_minimum_required(VERSION 3.20.0)
+
+# Pull in the dts/ and boards/ from prstlib.
+set(DTS_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../../prstlib)
+set(BOARD_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/../../prstlib)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+project(input)
+
+target_sources(app PRIVATE src/main.c)
+
+add_subdirectory(../../prstlib prstlib)
+target_include_directories(app PRIVATE ../../prstlib/include)
+target_link_libraries(app PUBLIC prstlib)

code/nrf-connect/samples/input/Kconfig

@@ -0,0 +1,3 @@
+
+source "Kconfig.zephyr"
+rsource "../../prstlib/Kconfig"

code/nrf-connect/samples/input/input.code-workspace

@@ -0,0 +1,16 @@
+{
+	"folders": [
+		{
+			"path": "."
+		},
+		{
+			"path": "../../prstlib"
+		}
+	],
+	"settings": {
+		"C_Cpp.autoAddFileAssociations": false,
+		"nrf-connect.applications": [
+			"${workspaceFolder}"
+		]
+	}
+}

code/nrf-connect/samples/input/prj.conf

@@ -0,0 +1,18 @@
+CONFIG_LOG=y
+CONFIG_PWM=y
+CONFIG_I2C=y
+CONFIG_ADC=y
+CONFIG_GPIO=y
+
+CONFIG_CBPRINTF_FP_SUPPORT=y
+
+CONFIG_SERIAL=n
+CONFIG_PM=y
+CONFIG_PM_DEVICE=y
+
+CONFIG_USE_SEGGER_RTT=y
+
+CONFIG_NEWLIB_LIBC=y
+CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
+
+CONFIG_PRSTLIB_LOG_LEVEL_DBG=y

code/nrf-connect/samples/input/src/main.c

@@ -0,0 +1,57 @@
+// #include <prstlib/button.h>
+// #include <prstlib/led.h>
+// #include <prstlib/sensors.h>
+// #include <zephyr/logging/log.h>
+// #include <zephyr/pm/device.h>
+// #include <zephyr/pm/pm.h>
+// #include <zephyr/pm/policy.h>
+#include <prstlib/adc.h>
+#include <prstlib/button.h>
+#include <prstlib/led.h>
+#include <prstlib/macros.h>
+#include <prstlib/sensors.h>
+#include <prstlib/shtc3.h>
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/pm/pm.h>
+#include <zephyr/pm/policy.h>
+
+LOG_MODULE_REGISTER(main, LOG_LEVEL_DBG);
+
+void button_pressed_cb(prst_button_t button, bool is_active) {
+  if (is_active) {
+    LOG_INF("Button pressed (debounced)");
+    prst_led_on();
+  } else {
+    LOG_INF("Button released (debounced)");
+    prst_led_off();
+  }
+}
+
+int main(void) {
+  RET_IF_ERR(prst_adc_init());
+  RET_IF_ERR(prst_led_init());
+  RET_IF_ERR(prst_button_init());
+
+  RET_IF_ERR(prst_led_flash(2));
+
+  prst_sensors_t sensors;
+  // Read the sensors just to ensure they'll be put to a low
+  // power mode afterward.
+  RET_IF_ERR(prst_sensors_read_all(&sensors));
+
+  int initial_button_state = prst_button_poll(PRST_BUTTON_SW1);
+  RET_CHECK(initial_button_state >= 0, "Failed to poll button");
+  LOG_INF("Initial button state: %s", initial_button_state ? "active" : "inactive");
+
+  RET_IF_ERR(prst_button_register_callback(button_pressed_cb));
+
+  RET_IF_ERR(prst_led_flash(2));
+
+  while (true) {
+    LOG_INF("Main loop.");
+    k_sleep(K_FOREVER);
+  }
+  return 0;
+}