RFC: Add HID bus type in hid_device_info (#308)

hidapi/hidapi.h

@@ -100,6 +100,37 @@ extern "C" {
 		struct hid_device_;
 		typedef struct hid_device_ hid_device; /**< opaque hidapi structure */
 
+		/** @brief HID underlying bus types.
+
+			@ingroup API
+		*/
+		typedef enum {
+			/* Unknown bus type */
+			HID_API_BUS_UNKNOWN = 0x00,
+
+			/* USB bus
+			   Specifications:
+			   https://usb.org/hid */
+			HID_API_BUS_USB = 0x01,
+
+			/* Bluetooth or Bluetooth LE bus
+			   Specifications:
+			   https://www.bluetooth.com/specifications/specs/human-interface-device-profile-1-1-1/
+			   https://www.bluetooth.com/specifications/specs/hid-service-1-0/
+			   https://www.bluetooth.com/specifications/specs/hid-over-gatt-profile-1-0/ */
+			HID_API_BUS_BLUETOOTH = 0x02,
+
+			/* I2C bus
+			   Specifications:
+			   https://docs.microsoft.com/previous-versions/windows/hardware/design/dn642101(v=vs.85) */
+			HID_API_BUS_I2C = 0x03,
+
+			/* SPI bus
+			   Specifications:
+			   https://www.microsoft.com/download/details.aspx?id=103325 */
+			HID_API_BUS_SPI = 0x04,
+		} hid_bus_type;
+
 		/** hidapi info structure */
 		struct hid_device_info {
 			/** Platform-specific device path */
@@ -135,6 +166,11 @@ extern "C" {
 
 			/** Pointer to the next device */
 			struct hid_device_info *next;
+
+			/** Underlying bus type
+			    Since version 0.13.0, @ref HID_API_VERSION >= HID_API_MAKE_VERSION(0, 13, 0)
+			*/
+			hid_bus_type bus_type;
 		};
 
 

hidtest/test.c

@@ -60,6 +60,7 @@ void print_device(struct hid_device_info *cur_dev) {
 	printf("  Release:      %hx\n", cur_dev->release_number);
 	printf("  Interface:    %d\n",  cur_dev->interface_number);
 	printf("  Usage (page): 0x%hx (0x%hx)\n", cur_dev->usage, cur_dev->usage_page);
+	printf("  Bus type: %d\n", cur_dev->bus_type);
 	printf("\n");
 }
 

libusb/hid.c

@@ -651,6 +651,8 @@ static struct hid_device_info * create_device_info_for_device(libusb_device *dev
 
 	cur_dev->interface_number = interface_num;
 
+	cur_dev->bus_type = HID_API_BUS_USB;
+
 	cur_dev->path = make_path(device, config_number, interface_num);
 
 	if (!handle) {

linux/hid.c

@@ -672,11 +672,11 @@ static struct hid_device_info * create_device_info_for_device(struct udev_device
 				break;
 			}
 
-			/* Manufacturer and Product strings */
 			cur_dev->manufacturer_string = copy_udev_string(usb_dev, "manufacturer");
 			cur_dev->product_string = copy_udev_string(usb_dev, "product");
 
-			/* Release Number */
+			cur_dev->bus_type = HID_API_BUS_USB;
+
 			str = udev_device_get_sysattr_value(usb_dev, "bcdDevice");
 			cur_dev->release_number = (str)? strtol(str, NULL, 16): 0x0;
 
@@ -693,11 +693,18 @@ static struct hid_device_info * create_device_info_for_device(struct udev_device
 			break;
 
 		case BUS_BLUETOOTH:
+			cur_dev->manufacturer_string = wcsdup(L"");
+			cur_dev->product_string = utf8_to_wchar_t(product_name_utf8);
+
+			cur_dev->bus_type = HID_API_BUS_BLUETOOTH;
+
+			break;
 		case BUS_I2C:
-			/* Manufacturer and Product strings */
 			cur_dev->manufacturer_string = wcsdup(L"");
 			cur_dev->product_string = utf8_to_wchar_t(product_name_utf8);
 
+			cur_dev->bus_type = HID_API_BUS_I2C;
+
 			break;
 
 		default:
@@ -745,6 +752,7 @@ static struct hid_device_info * create_device_info_for_device(struct udev_device
 			cur_dev->product_string = prev_dev->product_string? wcsdup(prev_dev->product_string): NULL;
 			cur_dev->usage_page = page;
 			cur_dev->usage = usage;
+			cur_dev->bus_type = prev_dev->bus_type;
 		}
 	}
 

mac/hid.c

@@ -378,6 +378,7 @@ static struct hid_device_info *create_device_info_with_usage(IOHIDDeviceRef dev,
 	unsigned short dev_pid;
 	int BUF_LEN = 256;
 	wchar_t buf[BUF_LEN];
+	CFTypeRef transport_prop;
 
 	struct hid_device_info *cur_dev;
 	io_object_t iokit_dev;
@@ -456,6 +457,22 @@ static struct hid_device_info *create_device_info_with_usage(IOHIDDeviceRef dev,
 		cur_dev->interface_number = -1;
 	}
 
+	/* Bus Type */
+	transport_prop = IOHIDDeviceGetProperty(dev, CFSTR(kIOHIDTransportKey));
+
+	if (transport_prop != NULL && CFGetTypeID(transport_prop) == CFStringGetTypeID()) {
+		if (CFStringCompare((CFStringRef)transport_prop, CFSTR(kIOHIDTransportUSBValue), 0) == kCFCompareEqualTo) {
+			cur_dev->bus_type = HID_API_BUS_USB;
+		/* Match "Bluetooth", "BluetoothLowEnergy" and "Bluetooth Low Energy" strings */
+		} else if (CFStringHasPrefix((CFStringRef)transport_prop, CFSTR(kIOHIDTransportBluetoothValue))) {
+			cur_dev->bus_type = HID_API_BUS_BLUETOOTH;
+		} else if (CFStringCompare((CFStringRef)transport_prop, CFSTR(kIOHIDTransportI2CValue), 0) == kCFCompareEqualTo) {
+			cur_dev->bus_type = HID_API_BUS_I2C;
+		} else  if (CFStringCompare((CFStringRef)transport_prop, CFSTR(kIOHIDTransportSPIValue), 0) == kCFCompareEqualTo) {
+			cur_dev->bus_type = HID_API_BUS_SPI;
+		}
+	}
+
 	return cur_dev;
 }
 

windows/hid.c

@@ -510,12 +510,43 @@ static void hid_internal_get_info(const wchar_t* interface_path, struct hid_devi
 		/* Normalize to upper case */
 		for (wchar_t* p = compatible_id; *p; ++p) *p = towupper(*p);
 
+		/* USB devices
+		   https://docs.microsoft.com/windows-hardware/drivers/hid/plug-and-play-support
+		   https://docs.microsoft.com/windows-hardware/drivers/install/standard-usb-identifiers */
+		if (wcsstr(compatible_id, L"USB") != NULL) {
+			dev->bus_type = HID_API_BUS_USB;
+			break;
+		}
+
+		/* Bluetooth devices
+		   https://docs.microsoft.com/windows-hardware/drivers/bluetooth/installing-a-bluetooth-device */
+		if (wcsstr(compatible_id, L"BTHENUM") != NULL) {
+			dev->bus_type = HID_API_BUS_BLUETOOTH;
+			break;
+		}
+
 		/* Bluetooth LE devices */
 		if (wcsstr(compatible_id, L"BTHLEDEVICE") != NULL) {
 			/* HidD_GetProductString/HidD_GetManufacturerString/HidD_GetSerialNumberString is not working for BLE HID devices
 			   Request this info via dev node properties instead.
 			   https://docs.microsoft.com/answers/questions/401236/hidd-getproductstring-with-ble-hid-device.html */
 			hid_internal_get_ble_info(dev, dev_node);
+
+			dev->bus_type = HID_API_BUS_BLUETOOTH;
+			break;
+		}
+
+		/* I2C devices
+		   https://docs.microsoft.com/windows-hardware/drivers/hid/plug-and-play-support-and-power-management */
+		if (wcsstr(compatible_id, L"PNP0C50") != NULL) {
+			dev->bus_type = HID_API_BUS_I2C;
+			break;
+		}
+
+		/* SPI devices
+		   https://docs.microsoft.com/windows-hardware/drivers/hid/plug-and-play-for-spi */
+		if (wcsstr(compatible_id, L"PNP0C51") != NULL) {
+			dev->bus_type = HID_API_BUS_SPI;
 			break;
 		}
 	}