pbio/drv/usb_stm32: Simplify event loop and use pbio/os.

BCD and data handling happen separately, so we can have them chronologically in the process thread.

Also fix a revisit note for not needing a timer to resend the status. Since we recently introduced status scheduling by the host module, we can just re-schedule the latest on subscribing.

Also introduce shutting down via pbdrv_deinit rather than polling statuses from pbsys.

Author: laurensvalk

lib/pbio/drv/core.c

@@ -90,6 +90,7 @@ void pbdrv_deinit(void) {
     pbdrv_imu_deinit();
     pbdrv_bluetooth_deinit();
     pbdrv_button_deinit();
+    pbdrv_usb_deinit();
 
     while (pbio_busy_count_busy()) {
         pbio_os_run_processes_and_wait_for_event();

lib/pbio/drv/usb/usb.h

@@ -11,13 +11,19 @@
 #if PBDRV_CONFIG_USB
 
 /**
- * Initializes the USB driver.
+ * Initializes the USB driver on boot.
  */
 void pbdrv_usb_init(void);
 
+/**
+ * De-initializes the USB driver for data transfers on soft-poweroff. Keeps charging if supported.
+ */
+void pbdrv_usb_deinit(void);
+
 #else // PBDRV_CONFIG_USB
 
 #define pbdrv_usb_init()
+#define pbdrv_usb_deinit()
 
 #endif // PBDRV_CONFIG_USB
 

lib/pbio/drv/usb/usb_ev3.c

@@ -1110,6 +1110,10 @@ void pbdrv_usb_init(void) {
     pbio_os_process_start(&pbdrv_usb_ev3_process, pbdrv_usb_ev3_process_thread, NULL);
 }
 
+void pbdrv_usb_deinit(void) {
+    // todo
+}
+
 pbdrv_usb_bcd_t pbdrv_usb_get_bcd(void) {
     // This function is not used on EV3
     return PBDRV_USB_BCD_NONE;

lib/pbio/drv/usb/usb_nxt.c

@@ -852,6 +852,10 @@ void pbdrv_usb_init(void) {
     *AT91C_PIOA_CODR = (1 << 16);
 }
 
+void pbdrv_usb_deinit(void) {
+    // todo
+}
+
 bool nx_usb_can_write(void) {
     return pbdrv_usb_nxt_state.status == USB_READY;
 }