Create VBUS disable interface in shared supervisor

ports/stm32f4/boards/stm32f411ce_blackpill/mpconfigboard.h

@@ -33,6 +33,7 @@
 #define FLASH_PAGE_SIZE             (0x4000)
 
 #define BOARD_OSC_DIV 25
+#define BOARD_NO_VBUS
 
 // On-board flash
 // #define SPI_FLASH_MOSI_PIN          (&pin_PA07)

ports/stm32f4/supervisor/usb.c

@@ -43,6 +43,7 @@ void init_usb_hardware(void) {
     PA11     ------> USB_OTG_FS_DM
     PA12     ------> USB_OTG_FS_DP 
     */
+
     __HAL_RCC_GPIOA_CLK_ENABLE();
 
       /* Configure DM DP Pins */
@@ -58,7 +59,7 @@ void init_usb_hardware(void) {
     /* Configure VBUS Pin */
     GPIO_InitStruct.Pin = GPIO_PIN_9;
     GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
-    GPIO_InitStruct.Pull = GPIO_NOPULL; 
+    GPIO_InitStruct.Pull = GPIO_NOPULL;
     HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
     never_reset_pin_number(0, 9);
 
@@ -83,3 +84,9 @@ void init_usb_hardware(void) {
     /* Peripheral clock enable */
     __HAL_RCC_USB_OTG_FS_CLK_ENABLE();
 }
+
+void disable_usb_vbus(void) {
+    USB_OTG_FS->GCCFG |= USB_OTG_GCCFG_NOVBUSSENS;
+    USB_OTG_FS->GCCFG &= ~USB_OTG_GCCFG_VBUSBSEN;
+    USB_OTG_FS->GCCFG &= ~USB_OTG_GCCFG_VBUSASEN;
+}

supervisor/shared/usb/usb.c

@@ -33,6 +33,8 @@
 #include "lib/utils/interrupt_char.h"
 #include "lib/mp-readline/readline.h"
 
+#include "py/mpconfig.h"
+
 #include "tusb.h"
 
 // Serial number as hex characters. This writes directly to the USB
@@ -72,6 +74,11 @@ void usb_init(void) {
 #if CIRCUITPY_USB_MIDI
     usb_midi_init();
 #endif
+
+#ifdef BOARD_NO_VBUS
+    disable_usb_vbus();
+#endif
+
 }
 
 void usb_background(void) {

supervisor/usb.h

@@ -37,6 +37,8 @@ void usb_background(void);
 // TinyUSB.
 void init_usb_hardware(void);
 
+void disable_usb_vbus(void);
+
 // Shared implementation.
 bool usb_enabled(void);
 void usb_init(void);