src/hardware/scpi-pps/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2014 Bert Vermeulen <bert@biot.com>
   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 <stdarg.h>
  22 #include "protocol.h"
  23
  24 SR_PRIV int scpi_cmd(const struct sr_dev_inst *sdi, int command, ...)
  25 {
  26         va_list args;
  27         struct dev_context *devc;
  28         struct sr_scpi_dev_inst *scpi;
  29         unsigned int i;
  30         int ret;
  31         char *cmd;
  32
  33         devc = sdi->priv;
  34         cmd = NULL;
  35         for (i = 0; i < devc->device->num_commands; i++) {
  36                 if (devc->device->commands[i].command == command) {
  37                         cmd = devc->device->commands[i].string;
  38                         break;
  39                 }
  40         }
  41         if (!cmd) {
  42                 /* Device does not implement this command, that's OK. */
  43                 return SR_OK_CONTINUE;
  44         }
  45
  46         scpi = sdi->conn;
  47         va_start(args, command);
  48         ret = sr_scpi_send_variadic(scpi, cmd, args);
  49         va_end(args);
  50
  51         return ret;
  52 }
  53
  54 SR_PRIV int scpi_pps_receive_data(int fd, int revents, void *cb_data)
  55 {
  56         struct dev_context *devc;
  57         struct sr_datafeed_packet packet;
  58         struct sr_datafeed_analog analog;
  59         const struct sr_dev_inst *sdi;
  60         struct sr_scpi_dev_inst *scpi;
  61         GSList *l;
  62         float f;
  63
  64         (void)fd;
  65         (void)revents;
  66
  67         if (!(sdi = cb_data))
  68                 return TRUE;
  69
  70         if (!(devc = sdi->priv))
  71                 return TRUE;
  72
  73         if (devc->state == STATE_STOP)
  74                 return TRUE;
  75
  76         scpi = sdi->conn;
  77
  78         /* Retrieve requested value for this state. */
  79         if (sr_scpi_get_float(scpi, NULL, &f) == SR_OK) {
  80                 packet.type = SR_DF_ANALOG;
  81                 packet.payload = &analog;
  82                 analog.channels = g_slist_append(NULL, devc->cur_channel);
  83                 analog.num_samples = 1;
  84                 if (devc->state == STATE_VOLTAGE) {
  85                         analog.mq = SR_MQ_VOLTAGE;
  86                         analog.unit = SR_UNIT_VOLT;
  87                 } else {
  88                         analog.mq = SR_MQ_CURRENT;
  89                         analog.unit = SR_UNIT_AMPERE;
  90                 }
  91                 analog.mqflags = SR_MQFLAG_DC;
  92                 analog.data = &f;
  93                 sr_session_send(sdi, &packet);
  94                 g_slist_free(analog.channels);
  95         }
  96
  97         if (devc->state == STATE_VOLTAGE) {
  98                 /* Just got voltage, request current for this channel. */
  99                 devc->state = STATE_CURRENT;
 100                 scpi_cmd(sdi, SCPI_CMD_GET_MEAS_CURRENT, devc->cur_channel->name);
 101         } else if (devc->state == STATE_CURRENT) {
 102                 /*
 103                  * Done with voltage and current for this channel, switch to
 104                  * the next enabled channel.
 105                  */
 106                 do {
 107                         l = g_slist_find(sdi->channels, devc->cur_channel);
 108                         if (l->next)
 109                                 devc->cur_channel = l->next->data;
 110                         else
 111                                 devc->cur_channel = sdi->channels->data;
 112                 } while (!devc->cur_channel->enabled);
 113
 114                 /* Request voltage. */
 115                 devc->state = STATE_VOLTAGE;
 116                 scpi_cmd(sdi, SCPI_CMD_GET_MEAS_VOLTAGE, devc->cur_channel->name);
 117         }
 118
 119         return TRUE;
 120 }