libsigrok/hardware/common/scpi_usbtmc.c

203 lines
4.9 KiB
C

/*
* 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>
#define LOG_PREFIX "scpi_usbtmc"
#define MAX_READ_LENGTH 2048
struct usbtmc_scpi {
struct sr_usbtmc_dev_inst *usbtmc;
char response_buffer[MAX_READ_LENGTH];
int response_length;
int response_bytes_read;
};
static int scpi_usbtmc_dev_inst_new(void *priv, const char *resource,
char **params, const char *serialcomm)
{
struct usbtmc_scpi *uscpi = priv;
(void)params;
(void)serialcomm;
if (!(uscpi->usbtmc = sr_usbtmc_dev_inst_new(resource)))
return SR_ERR;
return SR_OK;
}
static int scpi_usbtmc_open(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
struct sr_usbtmc_dev_inst *usbtmc = uscpi->usbtmc;
if ((usbtmc->fd = open(usbtmc->device, O_RDWR)) < 0)
return SR_ERR;
return SR_OK;
}
static int scpi_usbtmc_source_add(void *priv, int events, int timeout,
sr_receive_data_callback_t cb, void *cb_data)
{
struct usbtmc_scpi *uscpi = priv;
struct sr_usbtmc_dev_inst *usbtmc = uscpi->usbtmc;
return sr_source_add(usbtmc->fd, events, timeout, cb, cb_data);
}
static int scpi_usbtmc_source_remove(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
struct sr_usbtmc_dev_inst *usbtmc = uscpi->usbtmc;
return sr_source_remove(usbtmc->fd);
}
static int scpi_usbtmc_send(void *priv, const char *command)
{
struct usbtmc_scpi *uscpi = priv;
struct sr_usbtmc_dev_inst *usbtmc = uscpi->usbtmc;
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;
}
static int scpi_usbtmc_read_begin(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
struct sr_usbtmc_dev_inst *usbtmc = uscpi->usbtmc;
int len;
len = read(usbtmc->fd, uscpi->response_buffer, MAX_READ_LENGTH);
if (len < 0) {
sr_err("Read error: %s", strerror(errno));
return SR_ERR;
}
uscpi->response_length = len;
uscpi->response_bytes_read = 0;
sr_spew("Read %d bytes from device into buffer", len);
return SR_OK;
}
static int scpi_usbtmc_read_data(void *priv, char *buf, int maxlen)
{
struct usbtmc_scpi *uscpi = priv;
int read_length;
sr_spew("%d bytes requested", maxlen);
if (uscpi->response_bytes_read == uscpi->response_length) {
sr_spew("Buffer is empty.");
if (uscpi->response_length == MAX_READ_LENGTH) {
sr_spew("Previous read was of maximum length, reading again.");
if (scpi_usbtmc_read_begin(uscpi) != SR_OK)
return SR_ERR;
} else {
return SR_ERR;
}
}
read_length = uscpi->response_length - uscpi->response_bytes_read;
if (read_length > maxlen)
read_length = maxlen;
memcpy(buf, uscpi->response_buffer + uscpi->response_bytes_read, read_length);
uscpi->response_bytes_read += read_length;
sr_spew("Returned %d bytes from buffer, %d/%d bytes of buffer now read",
read_length, uscpi->response_bytes_read, uscpi->response_length);
return read_length;
}
static int scpi_usbtmc_read_complete(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
if (uscpi->response_length == MAX_READ_LENGTH
&& uscpi->response_bytes_read == uscpi->response_length)
scpi_usbtmc_read_begin(uscpi);
return (uscpi->response_bytes_read >= uscpi->response_length);
}
static int scpi_usbtmc_close(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
if (close(uscpi->usbtmc->fd) < 0)
return SR_ERR;
return SR_OK;
}
static void scpi_usbtmc_free(void *priv)
{
struct usbtmc_scpi *uscpi = priv;
sr_usbtmc_dev_inst_free(uscpi->usbtmc);
}
SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_dev = {
.name = "USBTMC",
.prefix = "/dev/usbtmc",
.priv_size = sizeof(struct usbtmc_scpi),
.dev_inst_new = scpi_usbtmc_dev_inst_new,
.open = scpi_usbtmc_open,
.source_add = scpi_usbtmc_source_add,
.source_remove = scpi_usbtmc_source_remove,
.send = scpi_usbtmc_send,
.read_begin = scpi_usbtmc_read_begin,
.read_data = scpi_usbtmc_read_data,
.read_complete = scpi_usbtmc_read_complete,
.close = scpi_usbtmc_close,
.free = scpi_usbtmc_free,
};