I am trying to figure out how to make a HCI USB Bluetooth host adapter with device management on a nRF52840 Dongle.
My approach is to make a USB composite device consisting of the Bluetooth device (CONFIG_USB_DEVICE_BLUETOOTH) and a CDC ACM UART (CONFIG_USB_CDC_ACM) which is used as backend for the MCU Manager Support (CONFIG_MCUMGR_SMP_UART).
When the nRF52840 Dongle is plugged into a USB port on a Linux machine, the serial device /dev/ttyACM0 is available and the SMP server is able to communicate with the mcumgr application. But the no Bluetooth adapter is detected.
Listing the device with lsusb shows that there is a Interface available that provides the Bluetooth protocol:
Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 2.00 bDeviceClass 239 Miscellaneous Device bDeviceSubClass 2 bDeviceProtocol 1 Interface Association bMaxPacketSize0 64 idVendor 0x2fe3 NordicSemiconductor idProduct 0x000b bcdDevice 2.05 iManufacturer 1 Manufacturer iProduct 2 Product iSerial 3 41EE42283B95248A bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0069 bNumInterfaces 3 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xc0 Self Powered MaxPower 100mA Interface Association: bLength 8 bDescriptorType 11 bFirstInterface 0 bInterfaceCount 2 bFunctionClass 2 Communications bFunctionSubClass 2 Abstract (modem) bFunctionProtocol 0 iFunction 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 2 Communications bInterfaceSubClass 2 Abstract (modem) bInterfaceProtocol 0 iInterface 0 CDC Header: bcdCDC 1.10 CDC Call Management: bmCapabilities 0x02 use DataInterface bDataInterface 1 CDC ACM: bmCapabilities 0x02 line coding and serial state CDC Union: bMasterInterface 0 bSlaveInterface 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0010 1x 16 bytes bInterval 10 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 10 CDC Data bInterfaceSubClass 0 bInterfaceProtocol 0 iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x01 EP 1 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 2 bAlternateSetting 0 bNumEndpoints 3 bInterfaceClass 224 Wireless bInterfaceSubClass 1 Radio Frequency bInterfaceProtocol 1 Bluetooth iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x83 EP 3 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x84 EP 4 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0040 1x 64 bytes bInterval 1
Am I missing something in the Zephyr kernel configuration? Or on the Linux host side? Is the approach with the composite USB device even feasible for what I want to achieve? Should I use another backend for the SMP server, e.g. udp?
Any suggestions or insights are appreciated, as I am by not very experienced with USB.
