Add GPIB SCPI backend using linux-gpib and libgpib.

Makefile.am

@@ -91,6 +91,10 @@ if NEED_VISA
 libsigrok_la_SOURCES += \
 	src/scpi/scpi_visa.c
 endif
+if NEED_GPIB
+libsigrok_la_SOURCES += \
+	src/scpi/scpi_gpib.c
+endif
 
 # Hardware (DMM chip parsers)
 libsigrok_la_SOURCES += \

configure.ac

@@ -316,6 +316,14 @@ if test "x$have_librevisa" != "xno"; then
 		[Specifies whether we have librevisa.])
 fi
 
+# GPIB backend is only compiled in if libgpib headers found.
+AC_CHECK_HEADERS([gpib/ib.h], [LIBS="$LIBS -lgpib"], [have_libgpib="no"])
+AM_CONDITIONAL(NEED_GPIB, test "x$have_libgpib" != xno)
+if test "x$have_libgpib" != "xno"; then
+	AC_DEFINE_UNQUOTED(HAVE_LIBGPIB, [1],
+		[Specifies whether we have libgpib.])
+fi
+
 # libusb-1.0 is only needed for some hardware drivers. Disable the respective
 # drivers if it is not found.
 if test "x$enable_libusb" != "xno"; then

src/scpi/scpi.c

@@ -71,6 +71,7 @@ SR_PRIV extern const struct sr_scpi_dev_inst scpi_tcp_rigol_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;
+SR_PRIV extern const struct sr_scpi_dev_inst scpi_gpib_dev;
 
 static const struct sr_scpi_dev_inst *scpi_devs[] = {
 	&scpi_tcp_raw_dev,
@@ -84,6 +85,9 @@ static const struct sr_scpi_dev_inst *scpi_devs[] = {
 #ifdef HAVE_LIBREVISA
 	&scpi_visa_dev,
 #endif
+#ifdef HAVE_LIBGPIB
+	&scpi_gpib_dev,
+#endif
 #ifdef HAVE_LIBSERIALPORT
 	&scpi_serial_dev,  /* must be last as it matches any resource */
 #endif

src/scpi/scpi_gpib.c

@@ -0,0 +1,166 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2014 Martin Ling <martin-sigrok@earth.li>
+ *
+ * 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 "libsigrok.h"
+#include "libsigrok-internal.h"
+
+#include <gpib/ib.h>
+#include <string.h>
+
+#define LOG_PREFIX "scpi_gpib"
+
+struct scpi_gpib {
+	char *name;
+	int descriptor;
+	int read_started;
+};
+
+static int scpi_gpib_dev_inst_new(void *priv, struct drv_context *drvc,
+		const char *resource, char **params, const char *serialcomm)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	(void)drvc;
+	(void)resource;
+	(void)serialcomm;
+
+	if (!params || !params[1])
+			return SR_ERR;
+
+	gscpi->name = g_strdup(params[1]);
+
+	return SR_OK;
+}
+
+static int scpi_gpib_open(void *priv)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	if ((gscpi->descriptor = ibfind(gscpi->name)) < 0)
+		return SR_ERR;
+
+	return SR_OK;
+}
+
+static int scpi_gpib_source_add(struct sr_session *session, void *priv,
+		int events, int timeout, sr_receive_data_callback cb, void *cb_data)
+{
+	(void) priv;
+
+	/* Hook up a dummy handler to receive data from the device. */
+	return sr_session_source_add(session, -1, events, timeout, cb, cb_data);
+}
+
+static int scpi_gpib_source_remove(struct sr_session *session, void *priv)
+{
+	(void) priv;
+
+	return sr_session_source_remove(session, -1);
+}
+
+static int scpi_gpib_send(void *priv, const char *command)
+{
+	struct scpi_gpib *gscpi = priv;
+	int len = strlen(command);
+
+	ibwrt(gscpi->descriptor, command, len);
+
+	if (ibsta & ERR)
+	{
+		sr_err("Error while sending SCPI command: '%s': iberr = %d.",
+				command, iberr);
+		return SR_ERR;
+	}
+
+	if (ibcnt < len)
+	{
+		sr_err("Failed to send all of SCPI command: '%s': "
+				"len = %d, ibcnt = .", command, len, ibcnt);
+		return SR_ERR;
+	}
+
+	sr_spew("Successfully sent SCPI command: '%s'.", command);
+
+	return SR_OK;
+}
+
+static int scpi_gpib_read_begin(void *priv)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	gscpi->read_started = 0;
+
+	return SR_OK;
+}
+
+static int scpi_gpib_read_data(void *priv, char *buf, int maxlen)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	ibrd(gscpi->descriptor, buf, maxlen);
+
+	if (ibsta & ERR)
+	{
+		sr_err("Error while reading SCPI response: iberr = %d.", iberr);
+		return SR_ERR;
+	}
+
+	gscpi->read_started = 1;
+
+	return ibcnt;
+}
+
+static int scpi_gpib_read_complete(void *priv)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	return gscpi->read_started && (ibsta & END);
+}
+
+static int scpi_gpib_close(void *priv)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	ibonl(gscpi->descriptor, 0);
+
+	return SR_OK;
+}
+
+static void scpi_gpib_free(void *priv)
+{
+	struct scpi_gpib *gscpi = priv;
+
+	g_free(gscpi->name);
+}
+
+SR_PRIV const struct sr_scpi_dev_inst scpi_gpib_dev = {
+	.name = "GPIB",
+	.prefix = "gpib",
+	.priv_size = sizeof(struct scpi_gpib),
+	.dev_inst_new = scpi_gpib_dev_inst_new,
+	.open = scpi_gpib_open,
+	.source_add = scpi_gpib_source_add,
+	.source_remove = scpi_gpib_source_remove,
+	.send = scpi_gpib_send,
+	.read_begin = scpi_gpib_read_begin,
+	.read_data = scpi_gpib_read_data,
+	.read_complete = scpi_gpib_read_complete,
+	.close = scpi_gpib_close,
+	.free = scpi_gpib_free,
+};