]> sigrok.org Git - libsigrok.git/commitdiff
scpi: add a libusb based implementation of usbtmc
authorAurelien Jacobs <redacted>
Fri, 17 Jan 2014 09:49:00 +0000 (10:49 +0100)
committerUwe Hermann <redacted>
Fri, 7 Feb 2014 17:53:04 +0000 (18:53 +0100)
hardware/common/Makefile.am
hardware/common/scpi.c
hardware/common/scpi_usbtmc_libusb.c [new file with mode: 0644]

index cdffe470c919b9d8f50cad9ba10c29e412e9b540..7e32ded659677cbfe88a18848718699a87cb6b37 100644 (file)
@@ -33,7 +33,7 @@ libsigrok_hw_common_la_SOURCES += serial.c scpi_serial.c
 endif
 
 if NEED_USB
-libsigrok_hw_common_la_SOURCES += ezusb.c usb.c
+libsigrok_hw_common_la_SOURCES += ezusb.c usb.c scpi_usbtmc_libusb.c
 endif
 
 if NEED_VISA
index 618ff058885ddb42b7b3661cbd4b6763f6e0e009..50fb94c4ae1cc2a4f1fc3f7092403eec94296176 100644 (file)
@@ -69,6 +69,7 @@ SR_PRIV extern const struct sr_scpi_dev_inst scpi_serial_dev;
 SR_PRIV extern const struct sr_scpi_dev_inst scpi_tcp_raw_dev;
 SR_PRIV extern const struct sr_scpi_dev_inst scpi_tcp_rigol_dev;
 SR_PRIV extern const struct sr_scpi_dev_inst scpi_usbtmc_dev;
+SR_PRIV extern const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev;
 SR_PRIV extern const struct sr_scpi_dev_inst scpi_vxi_dev;
 SR_PRIV extern const struct sr_scpi_dev_inst scpi_visa_dev;
 
@@ -76,6 +77,9 @@ static const struct sr_scpi_dev_inst *scpi_devs[] = {
        &scpi_tcp_raw_dev,
        &scpi_tcp_rigol_dev,
        &scpi_usbtmc_dev,
+#ifdef HAVE_LIBUSB_1_0
+       &scpi_usbtmc_libusb_dev,
+#endif
 #if HAVE_RPC
        &scpi_vxi_dev,
 #endif
diff --git a/hardware/common/scpi_usbtmc_libusb.c b/hardware/common/scpi_usbtmc_libusb.c
new file mode 100644 (file)
index 0000000..f66c972
--- /dev/null
@@ -0,0 +1,538 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+#include "libsigrok.h"
+#include "libsigrok-internal.h"
+
+#define LOG_PREFIX "scpi_usbtmc"
+
+#define MAX_TRANSFER_LENGTH 2048
+#define TRANSFER_TIMEOUT 1000
+
+struct scpi_usbtmc_libusb {
+       struct sr_context *ctx;
+       struct sr_usb_dev_inst *usb;
+       int detached_kernel_driver;
+       uint8_t interface;
+       uint8_t bulk_in_ep;
+       uint8_t bulk_out_ep;
+       uint8_t interrupt_ep;
+       uint8_t usbtmc_int_cap;
+       uint8_t usbtmc_dev_cap;
+       uint8_t usb488_dev_cap;
+       uint8_t bTag;
+       uint8_t bulkin_attributes;
+       uint8_t buffer[MAX_TRANSFER_LENGTH];
+       int response_length;
+       int response_bytes_read;
+       int remaining_length;
+};
+
+/* Some USBTMC-specific enums, as defined in the USBTMC standard. */
+#define SUBCLASS_USBTMC  0x03
+#define USBTMC_USB488    0x01
+
+enum {
+       /* USBTMC control requests */
+       INITIATE_ABORT_BULK_OUT     =   1,
+       CHECK_ABORT_BULK_OUT_STATUS =   2,
+       INITIATE_ABORT_BULK_IN      =   3,
+       CHECK_ABORT_BULK_IN_STATUS  =   4,
+       INITIATE_CLEAR              =   5,
+       CHECK_CLEAR_STATUS          =   6,
+       GET_CAPABILITIES            =   7,
+       INDICATOR_PULSE             =  64,
+
+       /* USB488 control requests */
+       READ_STATUS_BYTE            = 128,
+       REN_CONTROL                 = 160,
+       GO_TO_LOCAL                 = 161,
+       LOCAL_LOCKOUT               = 162,
+};
+
+/* USBTMC capabilities */
+#define USBTMC_INT_CAP_LISTEN_ONLY 0x01
+#define USBTMC_INT_CAP_TALK_ONLY   0x02
+#define USBTMC_INT_CAP_INDICATOR   0x04
+
+#define USBTMC_DEV_CAP_TERMCHAR    0x01
+
+#define USB488_DEV_CAP_DT1         0x01
+#define USB488_DEV_CAP_RL1         0x02
+#define USB488_DEV_CAP_SR1         0x04
+#define USB488_DEV_CAP_SCPI        0x08
+
+/* Bulk messages constants */
+#define USBTMC_BULK_HEADER_SIZE  12
+
+/* Bulk MsgID values */
+#define DEV_DEP_MSG_OUT         1
+#define REQUEST_DEV_DEP_MSG_IN  2
+#define DEV_DEP_MSG_IN          2
+
+/* bmTransferAttributes */
+#define EOM                0x01
+#define TERM_CHAR_ENABLED  0x02
+
+
+static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
+{
+       struct libusb_device **devlist;
+       struct libusb_device_descriptor des;
+       struct libusb_config_descriptor *confdes;
+       const struct libusb_interface_descriptor *intfdes;
+       GSList *resources = NULL;
+       int confidx, intfidx, ret, i;
+       char *res;
+
+       libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
+       for (i = 0; devlist[i]; i++) {
+               if ((ret = libusb_get_device_descriptor(devlist[i], &des))) {
+                       sr_err("Failed to get device descriptor: %s.",
+                              libusb_error_name(ret));
+                       continue;
+               }
+
+               for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
+                       if (libusb_get_config_descriptor(devlist[i], confidx, &confdes) != 0) {
+                               sr_err("Failed to get configuration descriptor.");
+                               break;
+                       }
+                       for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
+                               intfdes = confdes->interface[intfidx].altsetting;
+                               if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
+                                   intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
+                                   intfdes->bInterfaceProtocol != USBTMC_USB488)
+                                       continue;
+                               sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
+                                      "bus.address = %d.%d).", des.idVendor, des.idProduct,
+                                      libusb_get_bus_number(devlist[i]),
+                                      libusb_get_device_address(devlist[i]));
+                               res = g_strdup_printf("usbtmc/%d.%d",
+                                                     libusb_get_bus_number(devlist[i]),
+                                                     libusb_get_device_address(devlist[i]));
+                               resources = g_slist_append(resources, res);
+                       }
+                       libusb_free_config_descriptor(confdes);
+               }
+       }
+       libusb_free_device_list(devlist, 1);
+
+       sr_dbg("Found %d device(s).", g_slist_length(resources));
+
+       return resources;
+}
+
+static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
+               const char *resource, char **params, const char *serialcomm)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       GSList *devices;
+
+       (void)resource;
+       (void)serialcomm;
+
+       if (!params || !params[1]) {
+               sr_err("Invalid parameters.");
+               return SR_ERR;
+       }
+
+       uscpi->ctx = drvc->sr_ctx;
+       devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
+       if (g_slist_length(devices) != 1) {
+               sr_err("Failed to find USB device '%s'.", params[1]);
+               g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
+               return SR_ERR;
+       }
+       uscpi->usb = devices->data;
+       g_slist_free(devices);
+
+       return SR_OK;
+}
+
+static int scpi_usbtmc_libusb_open(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       struct sr_usb_dev_inst *usb = uscpi->usb;
+       struct libusb_device *dev;
+       struct libusb_device_descriptor des;
+       struct libusb_config_descriptor *confdes;
+       const struct libusb_interface_descriptor *intfdes;
+       const struct libusb_endpoint_descriptor *ep;
+       int confidx, intfidx, epidx, config = 0;
+       uint8_t capabilities[24];
+       int ret, found = 0;
+
+       if (usb->devhdl)
+               return SR_OK;
+
+       if (sr_usb_open(uscpi->ctx->libusb_ctx, usb) != SR_OK)
+               return SR_ERR;
+
+       dev = libusb_get_device(usb->devhdl);
+       if ((ret = libusb_get_device_descriptor(dev, &des))) {
+               sr_err("Failed to get device descriptor: %s.",
+                      libusb_error_name(ret));
+               return SR_ERR;
+       }
+
+       for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
+               if (libusb_get_config_descriptor(dev, confidx, &confdes) != 0) {
+                       sr_err("Failed to get configuration descriptor.");
+                       continue;
+               }
+               for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
+                       intfdes = confdes->interface[intfidx].altsetting;
+                       if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
+                           intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
+                           intfdes->bInterfaceProtocol != USBTMC_USB488)
+                               continue;
+                       uscpi->interface = intfdes->bInterfaceNumber;
+                       sr_dbg("Interface %d", uscpi->interface);
+                       config = confdes->bConfigurationValue;
+                       sr_dbg("Configuration %d", config);
+                       for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
+                               ep = &intfdes->endpoint[epidx];
+                               if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
+                                   !(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
+                                       uscpi->bulk_out_ep = ep->bEndpointAddress;
+                                       sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
+                               }
+                               if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
+                                   ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
+                                       uscpi->bulk_in_ep = ep->bEndpointAddress;
+                                       sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep);
+                               }
+                               if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
+                                   ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
+                                       uscpi->interrupt_ep = ep->bEndpointAddress;
+                                       sr_dbg("Interrupt EP %d", uscpi->interrupt_ep);
+                               }
+                       }
+                       found = 1;
+               }
+               libusb_free_config_descriptor(confdes);
+               if (found)
+                       break;
+       }
+
+       if (!found) {
+               sr_err("Failed to find USBTMC interface");
+               return SR_ERR;
+       }
+
+       if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
+               if ((ret = libusb_detach_kernel_driver(usb->devhdl,
+                                                      uscpi->interface)) < 0) {
+                       sr_err("failed to detach kernel driver: %s",
+                                       libusb_error_name(ret));
+                       return SR_ERR;
+               }
+               uscpi->detached_kernel_driver = 1;
+       }
+
+       if ((ret = libusb_set_configuration(usb->devhdl, config))) {
+               sr_err("Failed to set configuration: %s.", libusb_error_name(ret));
+               return SR_ERR;
+       }
+
+       if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface))) {
+               sr_err("Failed to claim interface: %s.", libusb_error_name(ret));
+               return SR_ERR;
+       }
+
+       libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep);
+       libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep);
+       libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep);
+
+       /* get capabilities */
+       ret = libusb_control_transfer(usb->devhdl,
+                                     LIBUSB_ENDPOINT_IN         |
+                                     LIBUSB_REQUEST_TYPE_CLASS  |
+                                     LIBUSB_RECIPIENT_INTERFACE,
+                                     GET_CAPABILITIES, 0,
+                                     uscpi->interface,
+                                     capabilities, sizeof(capabilities),
+                                     TRANSFER_TIMEOUT);
+       if (ret == sizeof(capabilities)) {
+               uscpi->usbtmc_int_cap = capabilities[ 4];
+               uscpi->usbtmc_dev_cap = capabilities[ 5];
+               uscpi->usb488_dev_cap = capabilities[15];
+       }
+       sr_dbg("device capabilities: %s%s%s%s%s, %s, %s",
+              uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI       ? "SCPI, "    : "",
+              uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR   ? "TermChar, ": "",
+              uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "L3, " :
+              uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? ""     : "L4, ",
+              uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? "T5, " :
+              uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? ""     : "T6, ",
+              uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1        ? "SR1"  : "SR0",
+              uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1        ? "RL1"  : "RL0",
+              uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1        ? "DT1"  : "DT0");
+
+       return SR_OK;
+}
+
+static int scpi_usbtmc_libusb_source_add(void *priv, int events, int timeout,
+                       sr_receive_data_callback_t cb, void *cb_data)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       (void)events;
+       return usb_source_add(uscpi->ctx, timeout, cb, cb_data);
+}
+
+static int scpi_usbtmc_libusb_source_remove(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       return usb_source_remove(uscpi->ctx);
+}
+
+static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
+                                         uint8_t bTag,
+                                         uint32_t TransferSize,
+                                         uint8_t bmTransferAttributes,
+                                         char TermChar)
+{
+         W8(header+ 0, MsgID);
+         W8(header+ 1, bTag);
+         W8(header+ 2, ~bTag);
+         W8(header+ 3, 0);
+       WL32(header+ 4, TransferSize);
+         W8(header+ 8, bmTransferAttributes);
+         W8(header+ 9, TermChar);
+       WL16(header+10, 0);
+}
+
+static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
+                                      unsigned char bTag,
+                                      int32_t *TransferSize,
+                                      uint8_t *bmTransferAttributes)
+{
+       if (R8(header+0) != MsgID ||
+           R8(header+1) != bTag  ||
+           R8(header+2) != (unsigned char)~bTag)
+               return SR_ERR;
+       if (TransferSize)
+               *TransferSize = RL32(header+4);
+       if (bmTransferAttributes)
+               *bmTransferAttributes = R8(header+8);
+       return SR_OK;
+}
+
+static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
+                               uint8_t msg_id, const void *data, int32_t size,
+                               uint8_t transfer_attributes)
+{
+       struct sr_usb_dev_inst *usb = uscpi->usb;
+       int padded_size, ret, transferred;
+
+       if (data && size+USBTMC_BULK_HEADER_SIZE+3 > (int)sizeof(uscpi->buffer)) {
+               sr_err("USBTMC bulk out transfer too big");
+               return SR_ERR;
+       }
+
+       uscpi->bTag++;
+       uscpi->bTag += !uscpi->bTag;  /* bTag == 0 is invalid so avoid it */
+
+       usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
+                                    size, transfer_attributes, 0);
+       if (data)
+               memcpy(uscpi->buffer+USBTMC_BULK_HEADER_SIZE, data, size);
+       else
+               size = 0;
+       size += USBTMC_BULK_HEADER_SIZE;
+       padded_size = (size + 3) & ~0x3;
+       memset(uscpi->buffer+size, 0, padded_size - size);
+
+       ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
+                                  uscpi->buffer, padded_size, &transferred,
+                                  TRANSFER_TIMEOUT);
+       if (ret) {
+               sr_err("USBTMC bulk out transfer error: %d", ret);
+               return SR_ERR;
+       }
+
+       if (transferred < padded_size) {
+               sr_dbg("USBTMC bulkout partial transfer (%d/%d bytes)",
+                      transferred, padded_size);
+               return SR_ERR;
+       }
+
+       return transferred - USBTMC_BULK_HEADER_SIZE;
+}
+
+static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
+                                    uint8_t msg_id, void *data, int32_t size,
+                                    uint8_t *transfer_attributes)
+{
+       struct sr_usb_dev_inst *usb = uscpi->usb;
+       int ret, transferred, message_size;
+
+       ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
+                                  &transferred, TRANSFER_TIMEOUT);
+       if (ret) {
+               sr_err("USBTMC bulk in transfer error: %d", ret);
+               return SR_ERR;
+       }
+
+       if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
+                                      transfer_attributes) != SR_OK) {
+               sr_err("USBTMC invalid bulk in header");
+               return SR_ERR;
+       }
+
+       message_size += USBTMC_BULK_HEADER_SIZE;
+       uscpi->response_length = MIN(transferred, message_size);
+       uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
+       uscpi->remaining_length = message_size - uscpi->response_length;
+
+       return transferred - USBTMC_BULK_HEADER_SIZE;
+}
+
+static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
+                                       void *data, int size)
+{
+       struct sr_usb_dev_inst *usb = uscpi->usb;
+       int ret, transferred;
+
+       ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
+                                  &transferred, TRANSFER_TIMEOUT);
+       if (ret) {
+               sr_err("USBTMC bulk in transfer error: %d", ret);
+               return SR_ERR;
+       }
+
+       uscpi->response_length = MIN(transferred, uscpi->remaining_length);
+       uscpi->response_bytes_read = 0;
+       uscpi->remaining_length -= uscpi->response_length;
+
+       return transferred;
+}
+
+static int scpi_usbtmc_libusb_send(void *priv, const char *command)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+
+       if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
+                               command, strlen(command), EOM) <= 0)
+               return SR_ERR;
+
+       sr_spew("Successfully sent SCPI command: '%s'.", command);
+
+       return SR_OK;
+}
+
+static int scpi_usbtmc_libusb_read_begin(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+
+       uscpi->remaining_length = 0;
+
+       if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
+           NULL, INT32_MAX, 0) < 0)
+               return SR_ERR;
+       if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
+                                    uscpi->buffer, sizeof(uscpi->buffer),
+                                    &uscpi->bulkin_attributes) < 0)
+               return SR_ERR;
+
+       return SR_OK;
+}
+
+static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       int read_length;
+
+       if (uscpi->response_bytes_read >= uscpi->response_length) {
+               if (uscpi->remaining_length > 0) {
+                       if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
+                                                       sizeof(uscpi->buffer)) <= 0)
+                               return SR_ERR;
+               } else {
+                       if (uscpi->bulkin_attributes & EOM)
+                               return SR_ERR;
+                       if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
+                               return SR_ERR;
+               }
+       }
+
+       read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
+
+       memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
+
+       uscpi->response_bytes_read += read_length;
+
+       return read_length;
+}
+
+static int scpi_usbtmc_libusb_read_complete(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       return uscpi->response_bytes_read >= uscpi->response_length &&
+              uscpi->remaining_length <= 0 &&
+              uscpi->bulkin_attributes & EOM;
+}
+
+static int scpi_usbtmc_libusb_close(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       struct sr_usb_dev_inst *usb = uscpi->usb;
+
+       if (!usb->devhdl)
+               return SR_ERR;
+
+       libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep);
+       libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep);
+       libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep);
+       libusb_release_interface(usb->devhdl, uscpi->interface);
+       if (uscpi->detached_kernel_driver) {
+               libusb_attach_kernel_driver(usb->devhdl, uscpi->interface);
+               uscpi->detached_kernel_driver = 0;
+       }
+       libusb_close(usb->devhdl);
+       usb->devhdl = NULL;
+
+       return SR_OK;
+}
+
+static void scpi_usbtmc_libusb_free(void *priv)
+{
+       struct scpi_usbtmc_libusb *uscpi = priv;
+       sr_usb_dev_inst_free(uscpi->usb);
+}
+
+
+SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
+       .name          = "USBTMC",
+       .prefix        = "usbtmc",
+       .priv_size     = sizeof(struct scpi_usbtmc_libusb),
+       .scan          = scpi_usbtmc_libusb_scan,
+       .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
+       .open          = scpi_usbtmc_libusb_open,
+       .source_add    = scpi_usbtmc_libusb_source_add,
+       .source_remove = scpi_usbtmc_libusb_source_remove,
+       .send          = scpi_usbtmc_libusb_send,
+       .read_begin    = scpi_usbtmc_libusb_read_begin,
+       .read_data     = scpi_usbtmc_libusb_read_data,
+       .read_complete = scpi_usbtmc_libusb_read_complete,
+       .close         = scpi_usbtmc_libusb_close,
+       .free          = scpi_usbtmc_libusb_free,
+};