[libsigrok.git] / hardware / common / scpi_usbtmc_libusb.c

/*
 * 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;
	int rigol_ds1000;
};

/* 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;

	ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
	if (ret < 0) {
		sr_err("Failed to get device list: %s.",
		       libusb_error_name(ret));
		return NULL;
	}
	for (i = 0; devlist[i]; i++) {
		if ((ret = libusb_get_device_descriptor(devlist[i], &des)) < 0) {
			sr_err("Failed to get device descriptor: %s.",
			       libusb_error_name(ret));
			continue;
		}

		for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
			if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
				sr_dbg("Failed to get configuration descriptor: %s, "
				       "ignoring device.", libusb_error_name(ret));
				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)) < 0) {
		sr_err("Failed to get device descriptor: %s.",
		       libusb_error_name(ret));
		return SR_ERR;
	}

	for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
		if ((ret = libusb_get_config_descriptor(dev, confidx, &confdes)) < 0) {
			sr_dbg("Failed to get configuration descriptor: %s, "
			       "ignoring device.", libusb_error_name(ret));
			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;
			uscpi->rigol_ds1000 = des.idVendor  == 0x1ab1 &&
			                      des.idProduct == 0x0588;
		}
		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)) < 0) {
		sr_err("Failed to set configuration: %s.",
		       libusb_error_name(ret));
		return SR_ERR;
	}

	if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
		sr_err("Failed to claim interface: %s.",
		       libusb_error_name(ret));
		return SR_ERR;
	}

	if (!uscpi->rigol_ds1000) {
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0) {
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->bulk_in_ep, libusb_error_name(ret));
		return SR_ERR;
	}
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0) {
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->bulk_out_ep, libusb_error_name(ret));
		return SR_ERR;
	}
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0) {
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->interrupt_ep, libusb_error_name(ret));
		return SR_ERR;
	}
	}

	/* 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(struct sr_session *session,
		void *priv, int events, int timeout, sr_receive_data_callback cb,
		void *cb_data)
{
	struct scpi_usbtmc_libusb *uscpi = priv;
	(void)events;
	return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
}

static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
		void *priv)
{
	struct scpi_usbtmc_libusb *uscpi = priv;
	return usb_source_remove(session, 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 is 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 < 0) {
		sr_err("USBTMC bulk out transfer error: %s.",
		       libusb_error_name(ret));
		return SR_ERR;
	}

	if (transferred < padded_size) {
		sr_dbg("USBTMC bulk out 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 < 0) {
		sr_err("USBTMC bulk in transfer error: %s.",
		       libusb_error_name(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 < 0) {
		sr_err("USBTMC bulk in transfer error: %s.",
		       libusb_error_name(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)
{
	int ret;
	struct scpi_usbtmc_libusb *uscpi = priv;
	struct sr_usb_dev_inst *usb = uscpi->usb;

	if (!usb->devhdl)
		return SR_ERR;

	if (!uscpi->rigol_ds1000) {
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0)
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->bulk_in_ep, libusb_error_name(ret));
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0)
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->bulk_out_ep, libusb_error_name(ret));
	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0)
		sr_err("Failed to clear halt/stall condition for EP %d: %s.",
		       uscpi->interrupt_ep, libusb_error_name(ret));
	}

	if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
		sr_err("Failed to release interface: %s.",
		       libusb_error_name(ret));
	
	if (uscpi->detached_kernel_driver) {
		if ((ret = libusb_attach_kernel_driver(usb->devhdl,
						uscpi->interface)) < 0)
			sr_err("Failed to re-attach kernel driver: %s.",
			       libusb_error_name(ret));

		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,
};
Commit	Line	Data
20ed3cee AJ	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
	5	*
	6	* This program is free software: you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation, either version 3 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <string.h>
	21	#include "libsigrok.h"
	22	#include "libsigrok-internal.h"
	23
	24	#define LOG_PREFIX "scpi_usbtmc"
	25
	26	#define MAX_TRANSFER_LENGTH 2048
	27	#define TRANSFER_TIMEOUT 1000
	28
	29	struct scpi_usbtmc_libusb {
	30	struct sr_context *ctx;
	31	struct sr_usb_dev_inst *usb;
	32	int detached_kernel_driver;
	33	uint8_t interface;
	34	uint8_t bulk_in_ep;
	35	uint8_t bulk_out_ep;
	36	uint8_t interrupt_ep;
	37	uint8_t usbtmc_int_cap;
	38	uint8_t usbtmc_dev_cap;
	39	uint8_t usb488_dev_cap;
	40	uint8_t bTag;
	41	uint8_t bulkin_attributes;
	42	uint8_t buffer[MAX_TRANSFER_LENGTH];
	43	int response_length;
	44	int response_bytes_read;
	45	int remaining_length;
50e6311a	46	int rigol_ds1000;
20ed3cee AJ	47	};
	48
	49	/* Some USBTMC-specific enums, as defined in the USBTMC standard. */
	50	#define SUBCLASS_USBTMC 0x03
	51	#define USBTMC_USB488 0x01
	52
	53	enum {
	54	/* USBTMC control requests */
	55	INITIATE_ABORT_BULK_OUT = 1,
	56	CHECK_ABORT_BULK_OUT_STATUS = 2,
	57	INITIATE_ABORT_BULK_IN = 3,
	58	CHECK_ABORT_BULK_IN_STATUS = 4,
	59	INITIATE_CLEAR = 5,
	60	CHECK_CLEAR_STATUS = 6,
	61	GET_CAPABILITIES = 7,
	62	INDICATOR_PULSE = 64,
	63
	64	/* USB488 control requests */
	65	READ_STATUS_BYTE = 128,
	66	REN_CONTROL = 160,
	67	GO_TO_LOCAL = 161,
	68	LOCAL_LOCKOUT = 162,
	69	};
	70
	71	/* USBTMC capabilities */
	72	#define USBTMC_INT_CAP_LISTEN_ONLY 0x01
	73	#define USBTMC_INT_CAP_TALK_ONLY 0x02
	74	#define USBTMC_INT_CAP_INDICATOR 0x04
	75
	76	#define USBTMC_DEV_CAP_TERMCHAR 0x01
	77
	78	#define USB488_DEV_CAP_DT1 0x01
	79	#define USB488_DEV_CAP_RL1 0x02
	80	#define USB488_DEV_CAP_SR1 0x04
	81	#define USB488_DEV_CAP_SCPI 0x08
	82
	83	/* Bulk messages constants */
	84	#define USBTMC_BULK_HEADER_SIZE 12
	85
	86	/* Bulk MsgID values */
	87	#define DEV_DEP_MSG_OUT 1
	88	#define REQUEST_DEV_DEP_MSG_IN 2
	89	#define DEV_DEP_MSG_IN 2
	90
	91	/* bmTransferAttributes */
	92	#define EOM 0x01
	93	#define TERM_CHAR_ENABLED 0x02
	94
	95
	96	static GSList scpi_usbtmc_libusb_scan(struct drv_context drvc)
	97	{
	98	struct libusb_device **devlist;
	99	struct libusb_device_descriptor des;
	100	struct libusb_config_descriptor *confdes;
	101	const struct libusb_interface_descriptor *intfdes;
	102	GSList *resources = NULL;
	103	int confidx, intfidx, ret, i;
	104	char *res;
	105
52f6951c UH	106	ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
	107	if (ret < 0) {
	108	sr_err("Failed to get device list: %s.",
	109	libusb_error_name(ret));
	110	return NULL;
	111	}
20ed3cee	112	for (i = 0; devlist[i]; i++) {
d8cbd659	113	if ((ret = libusb_get_device_descriptor(devlist[i], &des)) < 0) {
20ed3cee AJ	114	sr_err("Failed to get device descriptor: %s.",
	115	libusb_error_name(ret));
	116	continue;
	117	}
	118
	119	for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
9ad05e6c UH	120	if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
	121	sr_dbg("Failed to get configuration descriptor: %s, "
	122	"ignoring device.", libusb_error_name(ret));
20ed3cee AJ	123	break;
	124	}
	125	for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
	126	intfdes = confdes->interface[intfidx].altsetting;
	127	if (intfdes->bInterfaceClass != LIBUSB_CLASS_APPLICATION \|\|
	128	intfdes->bInterfaceSubClass != SUBCLASS_USBTMC \|\|
	129	intfdes->bInterfaceProtocol != USBTMC_USB488)
	130	continue;
	131	sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
	132	"bus.address = %d.%d).", des.idVendor, des.idProduct,
	133	libusb_get_bus_number(devlist[i]),
	134	libusb_get_device_address(devlist[i]));
	135	res = g_strdup_printf("usbtmc/%d.%d",
	136	libusb_get_bus_number(devlist[i]),
	137	libusb_get_device_address(devlist[i]));
	138	resources = g_slist_append(resources, res);
	139	}
	140	libusb_free_config_descriptor(confdes);
	141	}
	142	}
	143	libusb_free_device_list(devlist, 1);
	144
	145	sr_dbg("Found %d device(s).", g_slist_length(resources));
	146
	147	return resources;
	148	}
	149
	150	static int scpi_usbtmc_libusb_dev_inst_new(void priv, struct drv_context drvc,
	151	const char resource, char params, const char serialcomm)
	152	{
	153	struct scpi_usbtmc_libusb *uscpi = priv;
	154	GSList *devices;
	155
	156	(void)resource;
	157	(void)serialcomm;
	158
	159	if (!params \|\| !params[1]) {
	160	sr_err("Invalid parameters.");
	161	return SR_ERR;
	162	}
	163
	164	uscpi->ctx = drvc->sr_ctx;
	165	devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
	166	if (g_slist_length(devices) != 1) {
	167	sr_err("Failed to find USB device '%s'.", params[1]);
	168	g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
	169	return SR_ERR;
	170	}
	171	uscpi->usb = devices->data;
	172	g_slist_free(devices);
	173
	174	return SR_OK;
	175	}
	176
	177	static int scpi_usbtmc_libusb_open(void *priv)
	178	{
	179	struct scpi_usbtmc_libusb *uscpi = priv;
	180	struct sr_usb_dev_inst *usb = uscpi->usb;
	181	struct libusb_device *dev;
	182	struct libusb_device_descriptor des;
	183	struct libusb_config_descriptor *confdes;
	184	const struct libusb_interface_descriptor *intfdes;
	185	const struct libusb_endpoint_descriptor *ep;
	186	int confidx, intfidx, epidx, config = 0;
187	uint8_t capabilities[24];
188	int ret, found = 0;
189
190	if (usb->devhdl)
191	return SR_OK;
192
193	if (sr_usb_open(uscpi->ctx->libusb_ctx, usb) != SR_OK)
194	return SR_ERR;
195
196	dev = libusb_get_device(usb->devhdl);
d8cbd659	197	if ((ret = libusb_get_device_descriptor(dev, &des)) < 0) {
20ed3cee AJ	198	sr_err("Failed to get device descriptor: %s.",
	199	libusb_error_name(ret));
	200	return SR_ERR;
	201	}
	202
	203	for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
9ad05e6c UH	204	if ((ret = libusb_get_config_descriptor(dev, confidx, &confdes)) < 0) {
	205	sr_dbg("Failed to get configuration descriptor: %s, "
	206	"ignoring device.", libusb_error_name(ret));
20ed3cee AJ	207	continue;
	208	}
	209	for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
	210	intfdes = confdes->interface[intfidx].altsetting;
	211	if (intfdes->bInterfaceClass != LIBUSB_CLASS_APPLICATION \|\|
	212	intfdes->bInterfaceSubClass != SUBCLASS_USBTMC \|\|
	213	intfdes->bInterfaceProtocol != USBTMC_USB488)
	214	continue;
	215	uscpi->interface = intfdes->bInterfaceNumber;
	216	sr_dbg("Interface %d", uscpi->interface);
	217	config = confdes->bConfigurationValue;
	218	sr_dbg("Configuration %d", config);
	219	for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
	220	ep = &intfdes->endpoint[epidx];
	221	if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
	222	!(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
	223	uscpi->bulk_out_ep = ep->bEndpointAddress;
	224	sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
	225	}
	226	if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
	227	ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
	228	uscpi->bulk_in_ep = ep->bEndpointAddress;
	229	sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep);
	230	}
	231	if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
	232	ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
	233	uscpi->interrupt_ep = ep->bEndpointAddress;
	234	sr_dbg("Interrupt EP %d", uscpi->interrupt_ep);
	235	}
	236	}
	237	found = 1;
50e6311a AJ	238	uscpi->rigol_ds1000 = des.idVendor == 0x1ab1 &&
50e6311a AJ	239	des.idProduct == 0x0588;
20ed3cee AJ	240	}
	241	libusb_free_config_descriptor(confdes);
	242	if (found)
	243	break;
	244	}
	245
	246	if (!found) {
52f6951c	247	sr_err("Failed to find USBTMC interface.");
20ed3cee AJ	248	return SR_ERR;
	249	}
	250
	251	if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
	252	if ((ret = libusb_detach_kernel_driver(usb->devhdl,
	253	uscpi->interface)) < 0) {
52f6951c UH	254	sr_err("Failed to detach kernel driver: %s.",
52f6951c UH	255	libusb_error_name(ret));
20ed3cee AJ	256	return SR_ERR;
	257	}
	258	uscpi->detached_kernel_driver = 1;
	259	}
	260
d8cbd659	261	if ((ret = libusb_set_configuration(usb->devhdl, config)) < 0) {
52f6951c UH	262	sr_err("Failed to set configuration: %s.",
52f6951c UH	263	libusb_error_name(ret));
20ed3cee AJ	264	return SR_ERR;
	265	}
	266
d8cbd659	267	if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
52f6951c UH	268	sr_err("Failed to claim interface: %s.",
52f6951c UH	269	libusb_error_name(ret));
20ed3cee AJ	270	return SR_ERR;
	271	}
	272
f589a6d4	273	if (!uscpi->rigol_ds1000) {
52f6951c UH	274	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0) {
	275	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	276	uscpi->bulk_in_ep, libusb_error_name(ret));
	277	return SR_ERR;
	278	}
	279	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0) {
	280	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	281	uscpi->bulk_out_ep, libusb_error_name(ret));
	282	return SR_ERR;
	283	}
	284	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0) {
	285	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	286	uscpi->interrupt_ep, libusb_error_name(ret));
	287	return SR_ERR;
	288	}
f589a6d4	289	}
20ed3cee	290
52f6951c	291	/* Get capabilities. */
20ed3cee AJ	292	ret = libusb_control_transfer(usb->devhdl,
	293	LIBUSB_ENDPOINT_IN \|
	294	LIBUSB_REQUEST_TYPE_CLASS \|
	295	LIBUSB_RECIPIENT_INTERFACE,
	296	GET_CAPABILITIES, 0,
	297	uscpi->interface,
	298	capabilities, sizeof(capabilities),
	299	TRANSFER_TIMEOUT);
	300	if (ret == sizeof(capabilities)) {
	301	uscpi->usbtmc_int_cap = capabilities[ 4];
	302	uscpi->usbtmc_dev_cap = capabilities[ 5];
	303	uscpi->usb488_dev_cap = capabilities[15];
	304	}
52f6951c	305	sr_dbg("Device capabilities: %s%s%s%s%s, %s, %s",
20ed3cee AJ	306	uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI ? "SCPI, " : "",
	307	uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR ? "TermChar, ": "",
	308	uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "L3, " :
	309	uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY ? "" : "L4, ",
	310	uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY ? "T5, " :
	311	uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "" : "T6, ",
	312	uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1 ? "SR1" : "SR0",
	313	uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1 ? "RL1" : "RL0",
	314	uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1 ? "DT1" : "DT0");
	315
	316	return SR_OK;
	317	}
	318
102f1239 BV	319	static int scpi_usbtmc_libusb_source_add(struct sr_session *session,
	320	void *priv, int events, int timeout, sr_receive_data_callback cb,
	321	void *cb_data)
20ed3cee AJ	322	{
	323	struct scpi_usbtmc_libusb *uscpi = priv;
	324	(void)events;
102f1239	325	return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
20ed3cee AJ	326	}
20ed3cee AJ	327
102f1239 BV	328	static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
102f1239 BV	329	void *priv)
20ed3cee AJ	330	{
20ed3cee AJ	331	struct scpi_usbtmc_libusb *uscpi = priv;
102f1239	332	return usb_source_remove(session, uscpi->ctx);
20ed3cee AJ	333	}
	334
	335	static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
	336	uint8_t bTag,
	337	uint32_t TransferSize,
	338	uint8_t bmTransferAttributes,
	339	char TermChar)
	340	{
	341	W8(header+ 0, MsgID);
	342	W8(header+ 1, bTag);
	343	W8(header+ 2, ~bTag);
	344	W8(header+ 3, 0);
	345	WL32(header+ 4, TransferSize);
	346	W8(header+ 8, bmTransferAttributes);
	347	W8(header+ 9, TermChar);
	348	WL16(header+10, 0);
	349	}
	350
	351	static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
	352	unsigned char bTag,
	353	int32_t *TransferSize,
	354	uint8_t *bmTransferAttributes)
	355	{
	356	if (R8(header+0) != MsgID \|\|
	357	R8(header+1) != bTag \|\|
	358	R8(header+2) != (unsigned char)~bTag)
	359	return SR_ERR;
	360	if (TransferSize)
	361	*TransferSize = RL32(header+4);
	362	if (bmTransferAttributes)
	363	*bmTransferAttributes = R8(header+8);
	364	return SR_OK;
	365	}
	366
	367	static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
	368	uint8_t msg_id, const void *data, int32_t size,
	369	uint8_t transfer_attributes)
	370	{
	371	struct sr_usb_dev_inst *usb = uscpi->usb;
	372	int padded_size, ret, transferred;
	373
	374	if (data && size+USBTMC_BULK_HEADER_SIZE+3 > (int)sizeof(uscpi->buffer)) {
52f6951c	375	sr_err("USBTMC bulk out transfer is too big.");
20ed3cee AJ	376	return SR_ERR;
	377	}
	378
	379	uscpi->bTag++;
52f6951c	380	uscpi->bTag += !uscpi->bTag; /* bTag == 0 is invalid so avoid it. */
20ed3cee AJ	381
	382	usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
	383	size, transfer_attributes, 0);
	384	if (data)
	385	memcpy(uscpi->buffer+USBTMC_BULK_HEADER_SIZE, data, size);
	386	else
	387	size = 0;
	388	size += USBTMC_BULK_HEADER_SIZE;
	389	padded_size = (size + 3) & ~0x3;
	390	memset(uscpi->buffer+size, 0, padded_size - size);
	391
	392	ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
	393	uscpi->buffer, padded_size, &transferred,
	394	TRANSFER_TIMEOUT);
d8cbd659	395	if (ret < 0) {
52f6951c UH	396	sr_err("USBTMC bulk out transfer error: %s.",
52f6951c UH	397	libusb_error_name(ret));
20ed3cee AJ	398	return SR_ERR;
	399	}
	400
	401	if (transferred < padded_size) {
52f6951c	402	sr_dbg("USBTMC bulk out partial transfer (%d/%d bytes).",
20ed3cee AJ	403	transferred, padded_size);
	404	return SR_ERR;
	405	}
	406
	407	return transferred - USBTMC_BULK_HEADER_SIZE;
	408	}
	409
	410	static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
	411	uint8_t msg_id, void *data, int32_t size,
	412	uint8_t *transfer_attributes)
	413	{
	414	struct sr_usb_dev_inst *usb = uscpi->usb;
	415	int ret, transferred, message_size;
	416
	417	ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
	418	&transferred, TRANSFER_TIMEOUT);
d8cbd659	419	if (ret < 0) {
52f6951c UH	420	sr_err("USBTMC bulk in transfer error: %s.",
52f6951c UH	421	libusb_error_name(ret));
20ed3cee AJ	422	return SR_ERR;
	423	}
	424
	425	if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
	426	transfer_attributes) != SR_OK) {
52f6951c	427	sr_err("USBTMC invalid bulk in header.");
20ed3cee AJ	428	return SR_ERR;
	429	}
	430
	431	message_size += USBTMC_BULK_HEADER_SIZE;
	432	uscpi->response_length = MIN(transferred, message_size);
	433	uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
	434	uscpi->remaining_length = message_size - uscpi->response_length;
	435
	436	return transferred - USBTMC_BULK_HEADER_SIZE;
	437	}
	438
	439	static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
	440	void *data, int size)
	441	{
	442	struct sr_usb_dev_inst *usb = uscpi->usb;
	443	int ret, transferred;
	444
	445	ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
	446	&transferred, TRANSFER_TIMEOUT);
d8cbd659	447	if (ret < 0) {
52f6951c UH	448	sr_err("USBTMC bulk in transfer error: %s.",
52f6951c UH	449	libusb_error_name(ret));
20ed3cee AJ	450	return SR_ERR;
	451	}
	452
	453	uscpi->response_length = MIN(transferred, uscpi->remaining_length);
	454	uscpi->response_bytes_read = 0;
	455	uscpi->remaining_length -= uscpi->response_length;
	456
	457	return transferred;
	458	}
	459
	460	static int scpi_usbtmc_libusb_send(void priv, const char command)
	461	{
	462	struct scpi_usbtmc_libusb *uscpi = priv;
	463
	464	if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
	465	command, strlen(command), EOM) <= 0)
	466	return SR_ERR;
	467
	468	sr_spew("Successfully sent SCPI command: '%s'.", command);
	469
	470	return SR_OK;
	471	}
	472
	473	static int scpi_usbtmc_libusb_read_begin(void *priv)
	474	{
	475	struct scpi_usbtmc_libusb *uscpi = priv;
	476
	477	uscpi->remaining_length = 0;
	478
	479	if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
	480	NULL, INT32_MAX, 0) < 0)
	481	return SR_ERR;
	482	if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
	483	uscpi->buffer, sizeof(uscpi->buffer),
	484	&uscpi->bulkin_attributes) < 0)
	485	return SR_ERR;
	486
	487	return SR_OK;
	488	}
	489
	490	static int scpi_usbtmc_libusb_read_data(void priv, char buf, int maxlen)
	491	{
	492	struct scpi_usbtmc_libusb *uscpi = priv;
	493	int read_length;
	494
	495	if (uscpi->response_bytes_read >= uscpi->response_length) {
	496	if (uscpi->remaining_length > 0) {
	497	if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
	498	sizeof(uscpi->buffer)) <= 0)
	499	return SR_ERR;
	500	} else {
	501	if (uscpi->bulkin_attributes & EOM)
	502	return SR_ERR;
	503	if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
	504	return SR_ERR;
	505	}
	506	}
	507
	508	read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
	509
	510	memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
	511
	512	uscpi->response_bytes_read += read_length;
	513
514	return read_length;
515	}
516
517	static int scpi_usbtmc_libusb_read_complete(void *priv)
518	{
519	struct scpi_usbtmc_libusb *uscpi = priv;
520	return uscpi->response_bytes_read >= uscpi->response_length &&
521	uscpi->remaining_length <= 0 &&
522	uscpi->bulkin_attributes & EOM;
523	}
524
525	static int scpi_usbtmc_libusb_close(void *priv)
526	{
52f6951c	527	int ret;
20ed3cee AJ	528	struct scpi_usbtmc_libusb *uscpi = priv;
	529	struct sr_usb_dev_inst *usb = uscpi->usb;
	530
	531	if (!usb->devhdl)
	532	return SR_ERR;
	533
f589a6d4	534	if (!uscpi->rigol_ds1000) {
52f6951c UH	535	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0)
	536	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	537	uscpi->bulk_in_ep, libusb_error_name(ret));
	538	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0)
	539	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	540	uscpi->bulk_out_ep, libusb_error_name(ret));
	541	if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0)
	542	sr_err("Failed to clear halt/stall condition for EP %d: %s.",
	543	uscpi->interrupt_ep, libusb_error_name(ret));
f589a6d4	544	}
52f6951c UH	545
	546	if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
	547	sr_err("Failed to release interface: %s.",
	548	libusb_error_name(ret));
	549
20ed3cee	550	if (uscpi->detached_kernel_driver) {
52f6951c UH	551	if ((ret = libusb_attach_kernel_driver(usb->devhdl,
	552	uscpi->interface)) < 0)
	553	sr_err("Failed to re-attach kernel driver: %s.",
	554	libusb_error_name(ret));
	555
20ed3cee AJ	556	uscpi->detached_kernel_driver = 0;
	557	}
	558	libusb_close(usb->devhdl);
	559	usb->devhdl = NULL;
	560
	561	return SR_OK;
	562	}
	563
	564	static void scpi_usbtmc_libusb_free(void *priv)
	565	{
	566	struct scpi_usbtmc_libusb *uscpi = priv;
	567	sr_usb_dev_inst_free(uscpi->usb);
	568	}
	569
20ed3cee AJ	570	SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
	571	.name = "USBTMC",
	572	.prefix = "usbtmc",
	573	.priv_size = sizeof(struct scpi_usbtmc_libusb),
	574	.scan = scpi_usbtmc_libusb_scan,
	575	.dev_inst_new = scpi_usbtmc_libusb_dev_inst_new,
	576	.open = scpi_usbtmc_libusb_open,
	577	.source_add = scpi_usbtmc_libusb_source_add,
	578	.source_remove = scpi_usbtmc_libusb_source_remove,
	579	.send = scpi_usbtmc_libusb_send,
	580	.read_begin = scpi_usbtmc_libusb_read_begin,
	581	.read_data = scpi_usbtmc_libusb_read_data,
	582	.read_complete = scpi_usbtmc_libusb_read_complete,
	583	.close = scpi_usbtmc_libusb_close,
	584	.free = scpi_usbtmc_libusb_free,
	585	};