From a93cdfbeac32fcb36d5acc040344e7ae9d20e6fc Mon Sep 17 00:00:00 2001
From: Alan Ott <alan@signal11.us>
Date: Tue, 18 Jan 2011 22:52:06 -0500
Subject: [PATCH] Add the interface number to hid_device_info on Linux/libusb
 implementation.

The interface number is added to the hid_device_info struct. Since the
Linux/libusb implementation can't put the Usage and Usage Page in the
hid_device_info struct because it requires detaching the kernel driver, the
interface number is added instead so that users with composite HID devices
can differentiate between the interfaces on the device.
---
 hidapi/hidapi.h     | 9 +++++++--
 hidtest/hidtest.cpp | 1 +
 linux/hid-libusb.c  | 3 +++
 linux/hid.c         | 4 ++++
 mac/hid.c           | 3 +++
 windows/hid.cpp     | 3 +++
 6 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/hidapi/hidapi.h b/hidapi/hidapi.h
index 32943c0..a6b0d5d 100644
--- a/hidapi/hidapi.h
+++ b/hidapi/hidapi.h
@@ -62,10 +62,15 @@ extern "C" {
 			wchar_t *manufacturer_string;
 			/** Product string */
 			wchar_t *product_string;
-			/** Usage Page for this Device/Interface */
+			/** Usage Page for this Device/Interface
+			    (Windows/Mac only). */
 			unsigned short usage_page;
-			/** Usage for this Device/Interface */
+			/** Usage for this Device/Interface
+			    (Windows/Mac only).*/
 			unsigned short usage;
+			/** The USB interface which this logical device
+			    represents (Linux/libusb implementation only). */
+			int interface;
 
 			/** Pointer to the next device */
 			struct hid_device_info *next;
diff --git a/hidtest/hidtest.cpp b/hidtest/hidtest.cpp
index b48f4f3..fa776ba 100644
--- a/hidtest/hidtest.cpp
+++ b/hidtest/hidtest.cpp
@@ -51,6 +51,7 @@ int main(int argc, char* argv[])
 		printf("  Manufacturer: %ls\n", cur_dev->manufacturer_string);
 		printf("  Product:      %ls\n", cur_dev->product_string);
 		printf("  Release:      %hx\n", cur_dev->release_number);
+		printf("  Interface:    %d\n",  cur_dev->interface);
 		printf("\n");
 		cur_dev = cur_dev->next;
 	}
diff --git a/linux/hid-libusb.c b/linux/hid-libusb.c
index 52291a8..f6aa209 100644
--- a/linux/hid-libusb.c
+++ b/linux/hid-libusb.c
@@ -527,6 +527,9 @@ struct hid_device_info  HID_API_EXPORT *hid_enumerate(unsigned short vendor_id,
 
 							/* Release Number */
 							cur_dev->release_number = desc.bcdDevice;
+							
+							/* Interface Number */
+							cur_dev->interface = interface_num;
 						}
 					}
 				} /* altsettings */
diff --git a/linux/hid.c b/linux/hid.c
index 9a716c5..d8a58d1 100644
--- a/linux/hid.c
+++ b/linux/hid.c
@@ -299,6 +299,10 @@ struct hid_device_info  HID_API_EXPORT *hid_enumerate(unsigned short vendor_id,
 			/* Release Number */
 			str = udev_device_get_sysattr_value(dev, "bcdDevice");
 			cur_dev->release_number = (str)? strtol(str, NULL, 16): 0x0;
+			
+			/* Interface Number (Unsupported on Linux/hidraw) */
+			cur_dev->interface = -1;
+
 		}
 		else
 			goto next;
diff --git a/mac/hid.c b/mac/hid.c
index af10d81..67db48f 100644
--- a/mac/hid.c
+++ b/mac/hid.c
@@ -364,6 +364,9 @@ struct hid_device_info  HID_API_EXPORT *hid_enumerate(unsigned short vendor_id,
 
 			/* Release Number */
 			cur_dev->release_number = get_int_property(dev, CFSTR(kIOHIDVersionNumberKey));
+
+			/* Interface Number (Unsupported on Mac)*/
+			cur_dev->interface = -1;
 		}
 	}
 	
diff --git a/windows/hid.cpp b/windows/hid.cpp
index 4688215..148583c 100644
--- a/windows/hid.cpp
+++ b/windows/hid.cpp
@@ -359,6 +359,9 @@ struct hid_device_info HID_API_EXPORT * HID_API_CALL hid_enumerate(unsigned shor
 
 			/* Release Number */
 			cur_dev->release_number = attrib.VersionNumber;
+
+			/* Interface Number (Unsupported on Windows)*/
+			cur_dev->interface = -1;
 		}
 
 cont_close: