Battery measurement, basic version

firmware/libs/usb_mgmt/CMakeLists.txt

@@ -0,0 +1,5 @@
+if(CONFIG_USB_MGMT)
+  zephyr_library()
+  zephyr_library_sources(src/usb_mgmt.c)
+  zephyr_include_directories(include)
+endif()

firmware/libs/usb_mgmt/Kconfig

@@ -0,0 +1,13 @@
+menuconfig USB_MGMT
+    bool "USB Management"
+    default y
+    select NRFX_POWER
+    help
+      Library for USB-related queries, e.g. VBUS presence detection
+      via the nRF52840 POWER peripheral.
+
+if USB_MGMT
+    module = USB_MGMT
+    module-str = usb_mgmt
+    source "subsys/logging/Kconfig.template.log_config"
+endif # USB_MGMT

firmware/libs/usb_mgmt/include/usb_mgmt.h

@@ -0,0 +1,30 @@
+#ifndef USB_MGMT_H
+#define USB_MGMT_H
+
+#include <stdbool.h>
+#include <zephyr/kernel.h>
+
+#define USB_MGMT_VBUS_CONNECTED BIT(0)
+#define USB_MGMT_VBUS_DISCONNECTED BIT(1)
+
+extern struct k_event usb_mgmt_events;
+
+/**
+ * @brief Wait until usb_mgmt has completed initialization.
+ *
+ * @param timeout Timeout for waiting.
+ *
+ * @retval true usb_mgmt is ready.
+ * @retval false timeout occurred.
+ */
+bool usb_mgmt_wait_ready(k_timeout_t timeout);
+
+/**
+ * @brief Returns true when VBUS (USB 5 V) is present.
+ *
+ * Reads the USBREGSTATUS.VBUSDETECT bit in the nRF52840 POWER peripheral.
+ * No USB stack needs to be enabled.
+ */
+bool usb_mgmt_is_vbus_present(void);
+
+#endif /* USB_MGMT_H */

firmware/libs/usb_mgmt/src/usb_mgmt.c

@@ -0,0 +1,65 @@
+#include <hal/nrf_power.h>
+#include <nrfx_power.h>
+#include <errno.h>
+#include <zephyr/logging/log.h>
+
+#include "usb_mgmt.h"
+
+LOG_MODULE_REGISTER(usb_mgmt, CONFIG_USB_MGMT_LOG_LEVEL);
+
+K_EVENT_DEFINE(usb_mgmt_events);
+K_SEM_DEFINE(usb_mgmt_ready_sem, 0, 1);
+
+static bool usb_mgmt_last_vbus_state;
+static bool usb_mgmt_ready;
+
+static void usb_mgmt_power_handler(nrfx_power_usb_evt_t event)
+{
+	bool is_present = (event == NRFX_POWER_USB_EVT_DETECTED);
+
+	LOG_INF("VBUS %s (event=%u)", is_present ? "connected" : "disconnected", event);
+
+	if (is_present != usb_mgmt_last_vbus_state) {
+		usb_mgmt_last_vbus_state = is_present;
+		k_event_post(&usb_mgmt_events,
+			     is_present ? USB_MGMT_VBUS_CONNECTED : USB_MGMT_VBUS_DISCONNECTED);
+	}
+}
+
+static int usb_mgmt_init(void)
+{
+	usb_mgmt_last_vbus_state = nrf_power_usbregstatus_vbusdet_get(NRF_POWER);
+	LOG_DBG("Boot VBUS state: %s", usb_mgmt_last_vbus_state ? "present" : "absent");
+	k_event_post(&usb_mgmt_events,
+		     usb_mgmt_last_vbus_state ? USB_MGMT_VBUS_CONNECTED : USB_MGMT_VBUS_DISCONNECTED);
+
+	nrfx_power_config_t config = { 0 };
+	nrfx_power_usbevt_config_t usb_config = {
+		.handler = usb_mgmt_power_handler,
+	};
+
+	nrfx_power_init(&config);
+	nrfx_power_usbevt_init(&usb_config);
+	nrfx_power_usbevt_enable();
+
+	usb_mgmt_ready = true;
+	k_sem_give(&usb_mgmt_ready_sem);
+
+	return 0;
+}
+
+SYS_INIT(usb_mgmt_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);
+
+bool usb_mgmt_is_vbus_present(void)
+{
+	return usb_mgmt_last_vbus_state;
+}
+
+bool usb_mgmt_wait_ready(k_timeout_t timeout)
+{
+	if (usb_mgmt_ready) {
+		return true;
+	}
+
+	return k_sem_take(&usb_mgmt_ready_sem, timeout) == 0;
+}