boards/nucleo-l073rz: Add USB device support and a CDC/ACM configuration.

The STM32L073RZ provides a full speed USB device controller, but the
Nucleo-L073RZ board support did not enable it and no configuration
exercised it.

Add the pieces required to run USB device mode on this board:

- Add the USB device pin definitions to the STM32L0 pin map.
- Provide board level pull-up control using the embedded DP pull-up in
  USB_BCDR, and register the CDC/ACM class at boot when it is selected.
- Add a usb-cdc configuration that presents an NSH console on USART2 and
  a CDC/ACM serial device on USB.

The 48MHz clock for the controller is supplied by HSI48 trimmed from the
USB start of frame packet, which is the crystal-less USB configuration
already described by this board's board.h.

Assisted-by: GitHub Copilot:claude-opus-5
Signed-off-by: jsanchez-2g <jsanchez@2g-eng.com>

arch/arm/src/stm32l0/hardware/stm32l0_pinmap.h

@@ -320,7 +320,10 @@
 #define GPIO_USART5_TX_2    (GPIO_ALT | GPIO_PULLUP | GPIO_AF6 | GPIO_PUSHPULL | GPIO_PORTE | GPIO_PIN10)
 #define GPIO_USART5_TX_3    (GPIO_ALT | GPIO_PULLUP | GPIO_AF6 | GPIO_PUSHPULL | GPIO_PORTB | GPIO_PIN4)
 
-/* TODO: USB */
+/* USB */
+
+#define GPIO_USB_DM     (GPIO_ALT | GPIO_AF0 | GPIO_PORTA | GPIO_PIN11)
+#define GPIO_USB_DP     (GPIO_ALT | GPIO_AF0 | GPIO_PORTA | GPIO_PIN12)
 
 /* TODO: LPTIM */
 

boards/arm/stm32l0/nucleo-l073rz/configs/usb-cdc/defconfig

@@ -0,0 +1,62 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+CONFIG_ARCH="arm"
+CONFIG_ARCH_BOARD="nucleo-l073rz"
+CONFIG_ARCH_BOARD_NUCLEO_L073RZ=y
+CONFIG_ARCH_CHIP="stm32l0"
+CONFIG_ARCH_CHIP_STM32=y
+CONFIG_ARCH_CHIP_STM32L073RZ=y
+CONFIG_ARCH_CHIP_STM32L073XX=y
+CONFIG_ARCH_CHIP_STM32L0=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_BOARDCTL_USBDEVCTRL=y
+CONFIG_BOARD_LOOPSPERMSEC=2796
+CONFIG_BUILTIN=y
+CONFIG_CDCACM=y
+CONFIG_CDCACM_RXBUFSIZE=256
+CONFIG_CDCACM_TXBUFSIZE=256
+CONFIG_DEBUG_FEATURES=y
+CONFIG_DEBUG_FULLOPT=y
+CONFIG_DEBUG_SYMBOLS=y
+CONFIG_DEBUG_USB=y
+CONFIG_DISABLE_ENVIRON=y
+CONFIG_DISABLE_MQUEUE=y
+CONFIG_DISABLE_POSIX_TIMERS=y
+CONFIG_EXAMPLES_HELLO=y
+CONFIG_EXPERIMENTAL=y
+CONFIG_INIT_ENTRYPOINT="nsh_main"
+CONFIG_INIT_STACKSIZE=1536
+CONFIG_INTELHEX_BINARY=y
+CONFIG_LINE_MAX=64
+CONFIG_NFILE_DESCRIPTORS_PER_BLOCK=6
+CONFIG_NSH_BUILTIN_APPS=y
+CONFIG_NSH_FILEIOSIZE=64
+CONFIG_NSH_READLINE=y
+CONFIG_NUNGET_CHARS=0
+CONFIG_POSIX_SPAWN_DEFAULT_STACKSIZE=1536
+CONFIG_PTHREAD_MUTEX_UNSAFE=y
+CONFIG_PTHREAD_STACK_DEFAULT=1536
+CONFIG_RAM_SIZE=20480
+CONFIG_RAM_START=0x20000000
+CONFIG_RAW_BINARY=y
+CONFIG_RR_INTERVAL=200
+CONFIG_SCHED_WAITPID=y
+CONFIG_START_DAY=19
+CONFIG_START_MONTH=5
+CONFIG_START_YEAR=2013
+CONFIG_STDIO_DISABLE_BUFFERING=y
+CONFIG_STM32_HSI48=y
+CONFIG_STM32_PWR=y
+CONFIG_STM32_USART2=y
+CONFIG_STM32_USB=y
+CONFIG_STM32_VREFINT=y
+CONFIG_SYSTEM_NSH=y
+CONFIG_TASK_NAME_SIZE=0
+CONFIG_USART2_SERIAL_CONSOLE=y
+CONFIG_USBDEV_TRACE=y
+CONFIG_USBDEV_TRACE_STRINGS=y

boards/arm/stm32l0/nucleo-l073rz/include/board.h

@@ -94,6 +94,11 @@
 #  define STM32_HSI48_SYNCSRC   SYNCSRC_USB
 #endif
 
+#if defined(CONFIG_STM32_USB) && defined(CONFIG_USBDEV)
+int stm32_usb_setpullup(bool enable);
+bool stm32_usb_pullup_enabled(void);
+#endif
+
 /* TODO: timers */
 
 /* LED definitions **********************************************************/

boards/arm/stm32l0/nucleo-l073rz/src/stm32_boot.c

@@ -26,9 +26,17 @@
 
 #include <nuttx/config.h>
 
+#include <stdbool.h>
+
 #include <nuttx/board.h>
+#include <nuttx/irq.h>
+#include <nuttx/usb/usbdev.h>
+
 #include <arch/board/board.h>
 
+#include "arm_internal.h"
+#include "hardware/stm32_usbdev.h"
+#include "stm32_usbdev.h"
 #include "nucleo-l073rz.h"
 
 /****************************************************************************
@@ -77,6 +85,45 @@ void stm32_boardinitialize(void)
 #endif
 }
 
+#if defined(CONFIG_STM32_USB) && defined(CONFIG_USBDEV)
+int stm32_usb_setpullup(bool enable)
+{
+  irqstate_t flags;
+  uint16_t regval;
+
+  flags = enter_critical_section();
+  regval = getreg16(STM32_USB_BCDR);
+
+  if (enable)
+    {
+      regval |= USB_BCDR_DPPU;
+    }
+  else
+    {
+      regval &= ~USB_BCDR_DPPU;
+    }
+
+  putreg16(regval, STM32_USB_BCDR);
+  leave_critical_section(flags);
+
+  return OK;
+}
+
+bool stm32_usb_pullup_enabled(void)
+{
+  return (getreg16(STM32_USB_BCDR) & USB_BCDR_DPPU) != 0;
+}
+
+int stm32_usbpullup(FAR struct usbdev_s *dev, bool enable)
+{
+  return stm32_usb_setpullup(enable);
+}
+
+void stm32_usbsuspend(FAR struct usbdev_s *dev, bool resume)
+{
+}
+#endif
+
 /****************************************************************************
  * Name: board_late_initialize
  *

boards/arm/stm32l0/nucleo-l073rz/src/stm32_bringup.c

@@ -31,6 +31,7 @@
 
 #include <nuttx/board.h>
 #include <nuttx/leds/userled.h>
+#include <nuttx/usb/cdcacm.h>
 
 #include "nucleo-l073rz.h"
 
@@ -50,6 +51,10 @@
 #  define HAVE_DAC2 1
 #endif
 
+#if defined(CONFIG_CDCACM) && !defined(CONFIG_CDCACM_COMPOSITE)
+#  define HAVE_CDCACM 1
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -80,6 +85,14 @@ int stm32_bringup(void)
     }
 #endif
 
+#ifdef HAVE_CDCACM
+  ret = cdcacm_initialize(0, NULL);
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: Failed to register CDC ACM: %d\n", ret);
+    }
+#endif
+
 #ifdef CONFIG_ADC
   /* Initialize ADC and register the ADC driver. */