stm32fsdev: Implement dcd_connect.

src/device/dcd.h

@@ -106,11 +106,11 @@ void dcd_set_config (uint8_t rhport, uint8_t config_num);
 // Wake up host
 void dcd_remote_wakeup(uint8_t rhport);
 
-// disconnect by disabling internal pull-up resistor on D+/D-
-void dcd_disconnect(uint8_t rhport) TU_ATTR_WEAK;
-
-// connect by enabling internal pull-up resistor on D+/D-
+// Connect or disconnect D+/D- line pull-up resistor.
+// Defined as weak in dcd source if MCU has internal pull-up.
+// Can be strongly defined in BSP.
 void dcd_connect(uint8_t rhport) TU_ATTR_WEAK;
+void dcd_disconnect(uint8_t rhport) TU_ATTR_WEAK;
 
 //--------------------------------------------------------------------+
 // Endpoint API

src/device/usbd.c

@@ -332,6 +332,7 @@ bool tud_init (void)
 
   // Init device controller driver
   dcd_init(TUD_OPT_RHPORT);
+  tud_connect();
   dcd_int_enable(TUD_OPT_RHPORT);
 
   return true;

src/portable/st/stm32_fsdev/dcd_stm32_fsdev.c

@@ -239,17 +239,29 @@ void dcd_init (uint8_t rhport)
   }
   USB->CNTR |= USB_CNTR_RESETM | USB_CNTR_SOFM | USB_CNTR_ESOFM | USB_CNTR_CTRM | USB_CNTR_SUSPM | USB_CNTR_WKUPM;
   dcd_handle_bus_reset();
-
-  // And finally enable pull-up, which may trigger the RESET IRQ if the host is connected.
-  // (if this MCU has an internal pullup)
-#if defined(USB_BCDR_DPPU)
-  USB->BCDR |= USB_BCDR_DPPU;
-#else
-  // FIXME: callback to the user to ask them to twiddle a GPIO to disable/enable D+???
-#endif
-
+  
+  // Data-line pull-up is left disconnected.
 }
 
+// Define only on MCU with internal pull-up so BSP can override (needed on MCU without internal pull-up)
+#if defined(USB_BCDR_DPPU)
+
+TU_ATTR_WEAK
+void dcd_disconnect(uint8_t rhport)
+{
+  (void) rhport;
+  USB->BCDR &= ~(USB_BCDR_DPPU);
+}
+
+TU_ATTR_WEAK
+void dcd_connect(uint8_t rhport)
+{
+  (void) rhport;
+  USB->BCDR |= USB_BCDR_DPPU;
+}
+
+#endif
+
 // Enable device interrupt
 void dcd_int_enable (uint8_t rhport)
 {

src/portable/template/dcd_template.c

@@ -45,6 +45,20 @@ void dcd_init (uint8_t rhport)
   (void) rhport;
 }
 
+#if HAS_INTERNAL_PULLUP
+// Enable internal D+/D- pullup
+void dcd_connect(uint8_t rhport) TU_ATTR_WEAK
+{
+  (void) rhport;
+}
+
+// Disable internal D+/D- pullup
+void dcd_disconnect(uint8_t rhport) TU_ATTR_WEAK
+{
+  (void) rhport;
+}
+#endif
+
 // Enable device interrupt
 void dcd_int_enable (uint8_t rhport)
 {