Implement SCPI over USBTMC.

hardware/common/Makefile.am

@@ -25,7 +25,7 @@ noinst_LTLIBRARIES = libsigrok_hw_common.la
 libsigrok_hw_common_la_SOURCES =
 
 if NEED_SERIAL
-libsigrok_hw_common_la_SOURCES += serial.c scpi.c scpi_serial.c
+libsigrok_hw_common_la_SOURCES += serial.c scpi.c scpi_serial.c scpi_usbtmc.c
 endif
 
 if NEED_USB

hardware/common/scpi_usbtmc.c

@@ -0,0 +1,147 @@
+/*
+ * This file is part of the libsigrok project.
+ *
+ * Copyright (C) 2013 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 <glib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+/* Message logging helpers with subsystem-specific prefix string. */
+#define LOG_PREFIX "scpi_usbtmc: "
+#define sr_log(l, s, args...) sr_log(l, LOG_PREFIX s, ## args)
+#define sr_spew(s, args...) sr_spew(LOG_PREFIX s, ## args)
+#define sr_dbg(s, args...) sr_dbg(LOG_PREFIX s, ## args)
+#define sr_info(s, args...) sr_info(LOG_PREFIX s, ## args)
+#define sr_warn(s, args...) sr_warn(LOG_PREFIX s, ## args)
+
+SR_PRIV int scpi_usbtmc_open(void *priv)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+
+	if ((usbtmc->fd = open(usbtmc->device, O_RDWR)) < 0)
+		return SR_ERR;
+
+	return SR_OK;
+}
+
+SR_PRIV int scpi_usbtmc_source_add(void *priv, int events, int timeout,
+			sr_receive_data_callback_t cb, void *cb_data)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+
+	return sr_source_add(usbtmc->fd, events, timeout, cb, cb_data);
+}
+
+SR_PRIV int scpi_usbtmc_source_remove(void *priv)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+
+	return sr_source_remove(usbtmc->fd);
+}
+
+SR_PRIV int scpi_usbtmc_send(void *priv, const char *command)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+	int len, out;
+
+	len = strlen(command);
+	out = write(usbtmc->fd, command, len);
+
+	if (out < 0) {
+		sr_err("Write error: %s", strerror(errno));
+		return SR_ERR;
+	}
+
+	if (out < len) {
+		sr_dbg("Only sent %d/%d bytes of SCPI command: '%s'.", out,
+		       len, command);
+	}
+
+	sr_spew("Successfully sent SCPI command: '%s'.", command);
+
+	return SR_OK;
+}
+
+SR_PRIV int scpi_usbtmc_receive(void *priv, char **scpi_response)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+	GString *response;
+	char buf[256];
+	int len;
+
+	response = g_string_sized_new(1024);
+
+	len = read(usbtmc->fd, buf, sizeof(buf));
+
+	if (len < 0) {
+		sr_err("Read error: %s", strerror(errno));
+		g_string_free(response, TRUE);
+		return SR_ERR;
+	}
+
+	response = g_string_append_len(response, buf, len);
+
+	*scpi_response = response->str;
+
+	sr_dbg("SCPI response received (length %d): '%.50s'",
+	       response->len, response->str);
+
+	g_string_free(response, FALSE);
+
+	return SR_OK;
+}
+
+SR_PRIV int scpi_usbtmc_close(void *priv)
+{
+	struct sr_usbtmc_dev_inst *usbtmc = priv;
+
+	if (close(usbtmc->fd) < 0)
+		return SR_ERR;
+
+	return SR_OK;
+}
+
+SR_PRIV struct sr_scpi_dev_inst *scpi_usbtmc_dev_inst_new(const char *device)
+{
+	struct sr_scpi_dev_inst *scpi;
+	struct sr_usbtmc_dev_inst *usbtmc;
+
+	scpi = g_try_malloc(sizeof(struct sr_scpi_dev_inst));
+
+	if (!(usbtmc = sr_usbtmc_dev_inst_new(device)))
+	{
+		g_free(scpi);
+		return NULL;
+	}
+
+	scpi->open = scpi_usbtmc_open;
+	scpi->source_add = scpi_usbtmc_source_add;
+	scpi->source_remove = scpi_usbtmc_source_remove;
+	scpi->send = scpi_usbtmc_send;
+	scpi->receive = scpi_usbtmc_receive;
+	scpi->close = scpi_usbtmc_close;
+	scpi->free = sr_usbtmc_dev_inst_free;
+	scpi->priv = usbtmc;
+
+	return scpi;
+}

libsigrok-internal.h

@@ -334,6 +334,10 @@ SR_PRIV void sr_scpi_hw_info_free(struct sr_scpi_hw_info *hw_info);
 SR_PRIV struct sr_scpi_dev_inst *scpi_serial_dev_inst_new(const char *port,
 		        const char *serialcomm);
 
+/*--- hardware/common/scpi_usbtmc.c -----------------------------------------*/
+
+SR_PRIV struct sr_scpi_dev_inst *scpi_usbtmc_dev_inst_new(const char *device);
+
 /*--- hardware/common/dmm/es51922.c -----------------------------------------*/
 
 #define ES51922_PACKET_SIZE 14