libusb20: Add dev_open + be_device_foreach manuals

Manual pages for libusb20_open(3) and libusb20_be_device_foreach(3).

PR:			291675
MFC after:		3 days
Reviewed by:		adrian (usb), ziaee (manpages)
Differential Revision:	https://reviews.freebsd.org/D54231

lib/libusb/Makefile

@@ -1,5 +1,4 @@
 #
-#
 # Makefile for the FreeBSD specific LibUSB 2.0
 #
 
@@ -11,7 +10,8 @@ SRCS+=		libusb20_desc.c
 SRCS+=		libusb20_ugen20.c
 INCS+=		libusb20.h
 INCS+=		libusb20_desc.h
-MAN=		libusb.3 libusb20.3
+MAN=		libusb.3 libusb20.3 libusb20_be_device_foreach.3 \
+		libusb20_dev_open.3
 MKLINT=		no
 NOGCCERROR=
 PTHREAD_LIBS?=	-lpthread
@@ -229,7 +229,6 @@ MLINKS += libusb20.3 libusb20_dev_set_config_index.3
 MLINKS += libusb20.3 libusb20_dev_get_debug.3
 MLINKS += libusb20.3 libusb20_dev_get_fd.3
 MLINKS += libusb20.3 libusb20_dev_kernel_driver_active.3
-MLINKS += libusb20.3 libusb20_dev_open.3
 MLINKS += libusb20.3 libusb20_dev_process.3
 MLINKS += libusb20.3 libusb20_dev_request_sync.3
 MLINKS += libusb20.3 libusb20_dev_req_string_sync.3
@@ -261,7 +260,6 @@ MLINKS += libusb20.3 libusb20_be_get_quirk_name.3
 MLINKS += libusb20.3 libusb20_be_add_dev_quirk.3
 MLINKS += libusb20.3 libusb20_be_remove_dev_quirk.3
 MLINKS += libusb20.3 libusb20_be_alloc_default.3
-MLINKS += libusb20.3 libusb20_be_device_foreach.3
 MLINKS += libusb20.3 libusb20_be_dequeue_device.3
 MLINKS += libusb20.3 libusb20_be_enqueue_device.3
 MLINKS += libusb20.3 libusb20_be_free.3

lib/libusb/libusb20_be_device_foreach.3

@@ -0,0 +1,56 @@
+.\"
+.\" Copyright (c) 2025 Rick Parrish <unitrunker@unitrunker.net>
+.\"
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
+.Dd December 14, 2025
+.Dt LIBUSB20 3
+.Os
+.Sh NAME
+.Nm libusb20_be_device_foreach
+.Nd iterate connected USB devices
+.Sh SYNOPSIS
+.Lb libusb
+.In libusb20.h
+.Ft struct libusb20_device *
+.Fn libusb20_be_device_foreach "struct libusb20_backend *pbe" "struct libusb20_device *pdev"
+.Sh DESCRIPTION
+The
+.Nm
+function iterates connected USB devices, one device at a time.
+A backend pointer for
+.Fa pbe
+may be obtained by calling
+.Xr libusb20_be_alloc_default 3 .
+The starting value of
+.Fa pdev
+is NULL.
+Calling
+.Nm libusb20_be_device_foreach
+again with
+.Fa pdev
+set to the return value of the previous call yields the next device.
+To begin interacting with a USB device, pass the pointer in a call to
+.Xr libusb20_dev_open 3 .
+.Sh RETURN VALUES
+.Nm
+returns NULL for end of list.
+Otherwise this is a pointer to the next device.
+.Sh EXAMPLES
+.Bd -literal
+    #include <libusb20.h>
+    struct libusb20_backend *be = libusb20_be_alloc_default();
+    struct libusb20_device *device = NULL;
+    while ( (device = libusb20_be_device_foreach(be, device)) != NULL ) {
+        if (libusb20_dev_open(device, 0) == LIBUSB20_SUCCESS) {
+            /* do something */
+            libusb20_dev_close(device);
+        }
+    }
+    libusb20_be_free(be);
+.Ed
+.Sh SEE ALSO
+.Xr libusb20 3 ,
+.Xr libusb20_be_alloc_default 3 ,
+.Xr libusb20_be_free 3 ,
+.Xr libusb20_dev_open 3

lib/libusb/libusb20_dev_open.3

@@ -0,0 +1,69 @@
+.\"
+.\" Copyright (c) 2025 Rick Parrish <unitrunker@unitrunker.net>
+.\"
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
+.Dd December 14, 2025
+.Dt LIBUSB20 3
+.Os
+.Sh NAME
+.Nm libusb20_dev_open
+.Nd open a USB device to retrieve descriptors and initiate transfers
+.Sh SYNOPSIS
+.Lb libusb
+.In libusb20.h
+.Ft int
+.Fn libusb20_dev_open "struct libusb20_device *pdev" "uin16_t transfer_max"
+.Sh DESCRIPTION
+The
+.Nm
+function opens a USB device to retrieve descriptors and initiate transfers.
+.Nm
+accepts a pointer as
+.Fa pdev
+to a libusb20_device obtained from
+.Nm libusb20_be_device_foreach .
+A zero for
+.Fa transfer_max
+limits the device to only control transfers.
+Call
+.Xr libusb20_dev_close 3
+to free resources taken by the open device handle.
+.Sh RETURN VALUES
+.Nm
+returns one of the following to report success or failure:
+.Pp
+.Bl -tag -width "LIBUSB20_ERROR_NO_DEVICE," -compact
+.It Er LIBUSB20_SUCCESS ,
+The operation succeeds.
+.It Er LIBUSB20_ERROR_BUSY ,
+The device is in use elsewhere.
+.It Er LIBUSB20_ERROR_ACCESS ,
+A permissions issue.
+.It Er LIBUSB20_ERROR_NO_DEVICE ,
+The device detached.
+.It Er LIBUSB20_ERROR_NO_MEM
+The library couldn't allocate memory.
+.El
+.Pp
+Errors not listed here may be found in
+.Xr libusb20 3
+and
+.In libusb20.h .
+.Sh EXAMPLES
+.Bd -literal
+    #include <libusb20.h>
+    struct libusb20_backend *be = libusb20_be_alloc_default();
+    struct libusb20_device *device = NULL;
+    while ( (device = libusb20_be_device_foreach(be, device)) != NULL ) {
+        if (libusb20_dev_open(device, 0) == LIBUSB20_SUCCESS) {
+            /* do something */
+            libusb20_dev_close(device);
+        }
+    }
+    libusb20_be_free(be);
+.Ed
+.Sh SEE ALSO
+.Xr libusb20 3 ,
+.Xr libusb20_be_device_foreach 3 ,
+.Xr libusb20_dev_close 3