src/hardware/scpi-dmm/api.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2018 Gerhard Sittig <gerhard.sittig@gmx.net>
   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 "protocol.h"
  22
  23 static struct sr_dev_driver scpi_dmm_driver_info;
  24
  25 static const uint32_t scanopts[] = {
  26         SR_CONF_CONN,
  27         SR_CONF_SERIALCOMM,
  28 };
  29
  30 static const uint32_t drvopts[] = {
  31         SR_CONF_MULTIMETER,
  32 };
  33
  34 static const uint32_t devopts_generic[] = {
  35         SR_CONF_CONTINUOUS,
  36         SR_CONF_LIMIT_SAMPLES | SR_CONF_GET | SR_CONF_SET,
  37         SR_CONF_LIMIT_MSEC | SR_CONF_GET | SR_CONF_SET,
  38         SR_CONF_MEASURED_QUANTITY | SR_CONF_GET | SR_CONF_SET | SR_CONF_LIST,
  39 };
  40
  41 static const struct scpi_command cmdset_agilent[] = {
  42         { DMM_CMD_SETUP_REMOTE, "\n", },
  43         { DMM_CMD_SETUP_FUNC, "CONF:%s", },
  44         { DMM_CMD_QUERY_FUNC, "CONF?", },
  45         { DMM_CMD_START_ACQ, "MEAS", },
  46         { DMM_CMD_STOP_ACQ, "ABORT", },
  47         { DMM_CMD_QUERY_VALUE, "READ?", },
  48         { DMM_CMD_QUERY_PREC, "CONF?", },
  49         ALL_ZERO,
  50 };
  51
  52 /*
  53  * cmdset_hp is used for the 34401A, which was added to this code after the
  54  * 34405A and 34465A. It differs in starting the measurement with INIT: using
  55  * MEAS without a trailing '?' (as used for the 34405A) is not valid for the
  56  * 34401A and gives an error.
  57  * I'm surprised the same instruction sequence doesn't work and INIT may
  58  * work for both, but I don't have the others to re-test.
  59  *
  60  * cmdset_hp also works well for the 34410A, using cmdset_agilent throws an
  61  * error on 'MEAS' without a '?'.
  62  *
  63  * On the 34401A,
  64  *  MEAS <optional parameters> ? configures, arms, triggers and waits
  65  *       for a reading
  66  *  CONF <parameters> configures
  67  *  INIT prepares for triggering (trigger mode is not set, assumed
  68  *       internal - external might time out)
  69  *  *OPC waits for completion, and
  70  *  READ? retrieves the result
  71  */
  72 static const struct scpi_command cmdset_hp[] = {
  73         { DMM_CMD_SETUP_REMOTE, "\n", },
  74         { DMM_CMD_SETUP_FUNC, "CONF:%s", },
  75         { DMM_CMD_QUERY_FUNC, "CONF?", },
  76         { DMM_CMD_START_ACQ, "INIT", },
  77         { DMM_CMD_STOP_ACQ, "ABORT", },
  78         { DMM_CMD_QUERY_VALUE, "READ?", },
  79         { DMM_CMD_QUERY_PREC, "CONF?", },
  80         ALL_ZERO,
  81 };
  82
  83 static const struct scpi_command cmdset_gwinstek[] = {
  84         { DMM_CMD_SETUP_REMOTE, "SYST:REM", },
  85         { DMM_CMD_SETUP_LOCAL, "SYST:LOC", },
  86         { DMM_CMD_SETUP_FUNC, "CONF:%s", },
  87         { DMM_CMD_QUERY_FUNC, "CONF:STAT:FUNC?", },
  88         { DMM_CMD_START_ACQ, "*CLS;SYST:REM", },
  89         { DMM_CMD_QUERY_VALUE, "VAL1?", },
  90         { DMM_CMD_QUERY_PREC, "SENS:DET:RATE?", },
  91         ALL_ZERO,
  92 };
  93
  94 static const struct scpi_command cmdset_gwinstek_906x[] = {
  95         { DMM_CMD_SETUP_REMOTE, "SYST:REM", },
  96         { DMM_CMD_SETUP_LOCAL, "SYST:LOC", },
  97         { DMM_CMD_SETUP_FUNC, "CONF:%s", },
  98         { DMM_CMD_QUERY_FUNC, "CONF?", },
  99         { DMM_CMD_START_ACQ, "INIT", },
 100         { DMM_CMD_STOP_ACQ, "ABORT", },
 101         { DMM_CMD_QUERY_VALUE, "VAL1?", },
 102         { DMM_CMD_QUERY_PREC, "SENS:DET:RATE?", },
 103         ALL_ZERO,
 104 };
 105
 106 static const struct mqopt_item mqopts_agilent_34405a[] = {
 107         { SR_MQ_VOLTAGE, SR_MQFLAG_DC, "VOLT:DC", "VOLT ", NO_DFLT_PREC, },
 108         { SR_MQ_VOLTAGE, SR_MQFLAG_AC, "VOLT:AC", "VOLT:AC ", NO_DFLT_PREC, },
 109         { SR_MQ_CURRENT, SR_MQFLAG_DC, "CURR:DC", "CURR ", NO_DFLT_PREC, },
 110         { SR_MQ_CURRENT, SR_MQFLAG_AC, "CURR:AC", "CURR:AC ", NO_DFLT_PREC, },
 111         { SR_MQ_RESISTANCE, 0, "RES", "RES ", NO_DFLT_PREC, },
 112         { SR_MQ_CONTINUITY, 0, "CONT", "CONT", -1, },
 113         { SR_MQ_CAPACITANCE, 0, "CAP", "CAP ", NO_DFLT_PREC, },
 114         { SR_MQ_VOLTAGE, SR_MQFLAG_DC | SR_MQFLAG_DIODE, "DIOD", "DIOD", -4, },
 115         { SR_MQ_TEMPERATURE, 0, "TEMP", "TEMP ", NO_DFLT_PREC, },
 116         { SR_MQ_FREQUENCY, 0, "FREQ", "FREQ ", NO_DFLT_PREC, },
 117 };
 118
 119 static const struct mqopt_item mqopts_agilent_34401a[] = {
 120         { SR_MQ_VOLTAGE, SR_MQFLAG_DC, "VOLT:DC", "VOLT ", NO_DFLT_PREC, },
 121         { SR_MQ_VOLTAGE, SR_MQFLAG_AC, "VOLT:AC", "VOLT:AC ", NO_DFLT_PREC, },
 122         { SR_MQ_CURRENT, SR_MQFLAG_DC, "CURR:DC", "CURR ", NO_DFLT_PREC, },
 123         { SR_MQ_CURRENT, SR_MQFLAG_AC, "CURR:AC", "CURR:AC ", NO_DFLT_PREC, },
 124         { SR_MQ_RESISTANCE, 0, "RES", "RES ", NO_DFLT_PREC, },
 125         { SR_MQ_RESISTANCE, SR_MQFLAG_FOUR_WIRE, "FRES", "FRES ", NO_DFLT_PREC, },
 126         { SR_MQ_CONTINUITY, 0, "CONT", "CONT", -1, },
 127         { SR_MQ_VOLTAGE, SR_MQFLAG_DC | SR_MQFLAG_DIODE, "DIOD", "DIOD", -4, },
 128         { SR_MQ_FREQUENCY, 0, "FREQ", "FREQ ", NO_DFLT_PREC, },
 129         { SR_MQ_TIME, 0, "PER", "PER ", NO_DFLT_PREC, },
 130 };
 131
 132 static const struct mqopt_item mqopts_gwinstek_gdm8200a[] = {
 133         { SR_MQ_VOLTAGE, SR_MQFLAG_DC, "VOLT:DC", "01", NO_DFLT_PREC, },
 134         { SR_MQ_VOLTAGE, SR_MQFLAG_AC, "VOLT:AC", "02", NO_DFLT_PREC, },
 135         { SR_MQ_CURRENT, SR_MQFLAG_DC, "CURR:DC", "03", NO_DFLT_PREC, },
 136         { SR_MQ_CURRENT, SR_MQFLAG_AC, "CURR:AC", "04", NO_DFLT_PREC, },
 137         { SR_MQ_CURRENT, SR_MQFLAG_DC, "CURR:DC", "05", NO_DFLT_PREC, }, /* mA */
 138         { SR_MQ_CURRENT, SR_MQFLAG_AC, "CURR:AC", "06", NO_DFLT_PREC, }, /* mA */
 139         { SR_MQ_RESISTANCE, 0, "RES", "07", NO_DFLT_PREC, },
 140         { SR_MQ_RESISTANCE, SR_MQFLAG_FOUR_WIRE, "FRES", "16", NO_DFLT_PREC, },
 141         { SR_MQ_CONTINUITY, 0, "CONT", "13", -1, },
 142         { SR_MQ_VOLTAGE, SR_MQFLAG_DC | SR_MQFLAG_DIODE, "DIOD", "17", -4, },
 143         { SR_MQ_TEMPERATURE, 0, "TEMP", "09", NO_DFLT_PREC, }, /* Celsius */
 144         { SR_MQ_TEMPERATURE, 0, "TEMP", "15", NO_DFLT_PREC, }, /* Fahrenheit */
 145         { SR_MQ_FREQUENCY, 0, "FREQ", "08", NO_DFLT_PREC, },
 146         { SR_MQ_TIME, 0, "PER", "14", NO_DFLT_PREC, },
 147 };
 148
 149 static const struct mqopt_item mqopts_gwinstek_gdm906x[] = {
 150         { SR_MQ_VOLTAGE, SR_MQFLAG_DC, "VOLT:DC", "VOLT ", NO_DFLT_PREC, },
 151         { SR_MQ_VOLTAGE, SR_MQFLAG_AC, "VOLT:AC", "VOLT:AC", NO_DFLT_PREC, },
 152         { SR_MQ_CURRENT, SR_MQFLAG_DC, "CURR:DC", "CURR ", NO_DFLT_PREC, },
 153         { SR_MQ_CURRENT, SR_MQFLAG_AC, "CURR:AC", "CURR:AC", NO_DFLT_PREC, },
 154         { SR_MQ_RESISTANCE, 0, "RES", "RES", NO_DFLT_PREC, },
 155         { SR_MQ_RESISTANCE, SR_MQFLAG_FOUR_WIRE, "FRES", "FRES", NO_DFLT_PREC, },
 156         { SR_MQ_CONTINUITY, 0, "CONT", "CONT", -1, },
 157         { SR_MQ_VOLTAGE, SR_MQFLAG_DC | SR_MQFLAG_DIODE, "DIOD", "DIOD", -4, },
 158         { SR_MQ_TEMPERATURE, 0, "TEMP", "TEMP", NO_DFLT_PREC, },
 159         { SR_MQ_FREQUENCY, 0, "FREQ", "FREQ", NO_DFLT_PREC, },
 160         { SR_MQ_TIME, 0, "PER", "PER", NO_DFLT_PREC, },
 161         { SR_MQ_CAPACITANCE, 0, "CAP", "CAP", NO_DFLT_PREC, },
 162 };
 163
 164 SR_PRIV const struct scpi_dmm_model models[] = {
 165         {
 166                 "Agilent", "34405A",
 167                 1, 5, cmdset_agilent, ARRAY_AND_SIZE(mqopts_agilent_34405a),
 168                 scpi_dmm_get_meas_agilent,
 169                 ARRAY_AND_SIZE(devopts_generic),
 170                 0,
 171         },
 172         {
 173                 "Agilent", "34410A",
 174                 1, 6, cmdset_hp, ARRAY_AND_SIZE(mqopts_agilent_34405a),
 175                 scpi_dmm_get_meas_agilent,
 176                 ARRAY_AND_SIZE(devopts_generic),
 177                 0,
 178         },
 179         {
 180                 "GW", "GDM8251A",
 181                 1, 6, cmdset_gwinstek, ARRAY_AND_SIZE(mqopts_gwinstek_gdm8200a),
 182                 scpi_dmm_get_meas_gwinstek,
 183                 ARRAY_AND_SIZE(devopts_generic),
 184                 1000 * 2500,
 185         },
 186         {
 187                 "GW", "GDM8255A",
 188                 1, 6, cmdset_gwinstek, ARRAY_AND_SIZE(mqopts_gwinstek_gdm8200a),
 189                 scpi_dmm_get_meas_gwinstek,
 190                 ARRAY_AND_SIZE(devopts_generic),
 191                 1000 * 2500,
 192         },
 193         {
 194                 "GWInstek", "GDM9060",
 195                 1, 6, cmdset_gwinstek_906x, ARRAY_AND_SIZE(mqopts_gwinstek_gdm906x),
 196                 scpi_dmm_get_meas_agilent,
 197                 ARRAY_AND_SIZE(devopts_generic),
 198                 0,
 199         },
 200         {
 201                 "GWInstek", "GDM9061",
 202                 1, 6, cmdset_gwinstek_906x, ARRAY_AND_SIZE(mqopts_gwinstek_gdm906x),
 203                 scpi_dmm_get_meas_agilent,
 204                 ARRAY_AND_SIZE(devopts_generic),
 205                 0,
 206         },
 207         {
 208                 "HP", "34401A",
 209                 1, 6, cmdset_hp, ARRAY_AND_SIZE(mqopts_agilent_34401a),
 210                 scpi_dmm_get_meas_agilent,
 211                 ARRAY_AND_SIZE(devopts_generic),
 212                 /* 34401A: typ. 1020ms for AC readings (default is 1000ms). */
 213                 1000 * 1500,
 214         },
 215         {
 216                 "Keysight", "34465A",
 217                 1, 5, cmdset_agilent, ARRAY_AND_SIZE(mqopts_agilent_34405a),
 218                 scpi_dmm_get_meas_agilent,
 219                 ARRAY_AND_SIZE(devopts_generic),
 220                 0,
 221         },
 222 };
 223
 224 static const struct scpi_dmm_model *is_compatible(const char *vendor, const char *model)
 225 {
 226         size_t i;
 227         const struct scpi_dmm_model *entry;
 228
 229         for (i = 0; i < ARRAY_SIZE(models); i++) {
 230                 entry = &models[i];
 231                 if (!entry->vendor || !entry->model)
 232                         continue;
 233                 if (strcmp(vendor, entry->vendor) != 0)
 234                         continue;
 235                 if (strcmp(model, entry->model) != 0)
 236                         continue;
 237                 return entry;
 238         }
 239
 240         return NULL;
 241 }
 242
 243 static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 244 {
 245         struct sr_scpi_hw_info *hw_info;
 246         int ret;
 247         const char *vendor;
 248         const struct scpi_dmm_model *model;
 249         struct sr_dev_inst *sdi;
 250         struct dev_context *devc;
 251         size_t i;
 252         gchar *channel_name;
 253         const char *command;
 254
 255         scpi_dmm_cmd_delay(scpi);
 256         ret = sr_scpi_get_hw_id(scpi, &hw_info);
 257         if (ret != SR_OK) {
 258                 sr_info("Could not get IDN response.");
 259                 return NULL;
 260         }
 261         vendor = sr_vendor_alias(hw_info->manufacturer);
 262         model = is_compatible(vendor, hw_info->model);
 263         if (!model) {
 264                 sr_scpi_hw_info_free(hw_info);
 265                 return NULL;
 266         }
 267
 268         sdi = g_malloc0(sizeof(*sdi));
 269         sdi->vendor = g_strdup(hw_info->manufacturer);
 270         sdi->model = g_strdup(hw_info->model);
 271         sdi->version = g_strdup(hw_info->firmware_version);
 272         sdi->serial_num = g_strdup(hw_info->serial_number);
 273         sdi->conn = scpi;
 274         sdi->driver = &scpi_dmm_driver_info;
 275         sdi->inst_type = SR_INST_SCPI;
 276         sr_scpi_hw_info_free(hw_info);
 277         if (model->read_timeout_us)  /* non-default read timeout */
 278                 scpi->read_timeout_us = model->read_timeout_us;
 279         devc = g_malloc0(sizeof(*devc));
 280         sdi->priv = devc;
 281         devc->num_channels = model->num_channels;
 282         devc->cmdset = model->cmdset;
 283         devc->model = model;
 284
 285         for (i = 0; i < devc->num_channels; i++) {
 286                 channel_name = g_strdup_printf("P%zu", i + 1);
 287                 sr_channel_new(sdi, 0, SR_CHANNEL_ANALOG, TRUE, channel_name);
 288         }
 289
 290         /*
 291          * If device has DMM_CMD_SETUP_LOCAL command, send it now. To avoid
 292          * leaving device in remote mode (if only a "scan" is run).
 293          */
 294         command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_SETUP_LOCAL);
 295         if (command && *command) {
 296                 scpi_dmm_cmd_delay(scpi);
 297                 sr_scpi_send(scpi, command);
 298         }
 299
 300         return sdi;
 301 }
 302
 303 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 304 {
 305         return sr_scpi_scan(di->context, options, probe_device);
 306 }
 307
 308 static int dev_open(struct sr_dev_inst *sdi)
 309 {
 310         struct sr_scpi_dev_inst *scpi;
 311         int ret;
 312
 313         scpi = sdi->conn;
 314         ret = sr_scpi_open(scpi);
 315         if (ret < 0) {
 316                 sr_err("Failed to open SCPI device: %s.", sr_strerror(ret));
 317                 return SR_ERR;
 318         }
 319
 320         return SR_OK;
 321 }
 322
 323 static int dev_close(struct sr_dev_inst *sdi)
 324 {
 325         struct dev_context *devc;
 326         struct sr_scpi_dev_inst *scpi;
 327         const char *command;
 328
 329         devc = sdi->priv;
 330         scpi = sdi->conn;
 331         if (!scpi)
 332                 return SR_ERR_BUG;
 333
 334         sr_dbg("DIAG: sdi->status %d.", sdi->status - SR_ST_NOT_FOUND);
 335         if (sdi->status <= SR_ST_INACTIVE)
 336                 return SR_OK;
 337
 338         /*
 339          * If device has DMM_CMD_SETUP_LOCAL command, send it now
 340          * to avoid leaving device in remote mode.
 341          */
 342         command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_SETUP_LOCAL);
 343         if (command && *command) {
 344                 scpi_dmm_cmd_delay(scpi);
 345                 sr_scpi_send(scpi, command);
 346         }
 347
 348         return sr_scpi_close(scpi);
 349 }
 350
 351 static int config_get(uint32_t key, GVariant **data,
 352         const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 353 {
 354         struct dev_context *devc;
 355         enum sr_mq mq;
 356         enum sr_mqflag mqflag;
 357         GVariant *arr[2];
 358         int ret;
 359
 360         (void)cg;
 361
 362         devc = sdi->priv;
 363
 364         switch (key) {
 365         case SR_CONF_LIMIT_SAMPLES:
 366         case SR_CONF_LIMIT_MSEC:
 367                 return sr_sw_limits_config_get(&devc->limits, key, data);
 368         case SR_CONF_MEASURED_QUANTITY:
 369                 ret = scpi_dmm_get_mq(sdi, &mq, &mqflag, NULL, NULL);
 370                 if (ret != SR_OK)
 371                         return ret;
 372                 arr[0] = g_variant_new_uint32(mq);
 373                 arr[1] = g_variant_new_uint64(mqflag);
 374                 *data = g_variant_new_tuple(arr, ARRAY_SIZE(arr));
 375                 return SR_OK;
 376         default:
 377                 return SR_ERR_NA;
 378         }
 379 }
 380
 381 static int config_set(uint32_t key, GVariant *data,
 382         const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 383 {
 384         struct dev_context *devc;
 385         enum sr_mq mq;
 386         enum sr_mqflag mqflag;
 387         GVariant *tuple_child;
 388
 389         (void)cg;
 390
 391         devc = sdi->priv;
 392
 393         switch (key) {
 394         case SR_CONF_LIMIT_SAMPLES:
 395         case SR_CONF_LIMIT_MSEC:
 396                 return sr_sw_limits_config_set(&devc->limits, key, data);
 397         case SR_CONF_MEASURED_QUANTITY:
 398                 tuple_child = g_variant_get_child_value(data, 0);
 399                 mq = g_variant_get_uint32(tuple_child);
 400                 g_variant_unref(tuple_child);
 401                 tuple_child = g_variant_get_child_value(data, 1);
 402                 mqflag = g_variant_get_uint64(tuple_child);
 403                 g_variant_unref(tuple_child);
 404                 return scpi_dmm_set_mq(sdi, mq, mqflag);
 405         default:
 406                 return SR_ERR_NA;
 407         }
 408 }
 409
 410 static int config_list(uint32_t key, GVariant **data,
 411         const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 412 {
 413         struct dev_context *devc;
 414         GVariant *gvar, *arr[2];
 415         GVariantBuilder gvb;
 416         size_t i;
 417
 418         (void)cg;
 419
 420         devc = sdi ? sdi->priv : NULL;
 421
 422         switch (key) {
 423         case SR_CONF_SCAN_OPTIONS:
 424         case SR_CONF_DEVICE_OPTIONS:
 425                 if (!devc)
 426                         return STD_CONFIG_LIST(key, data, sdi, cg,
 427                                 scanopts, drvopts, devopts_generic);
 428                 return std_opts_config_list(key, data, sdi, cg,
 429                         ARRAY_AND_SIZE(scanopts), ARRAY_AND_SIZE(drvopts),
 430                         devc->model->devopts, devc->model->devopts_size);
 431         case SR_CONF_MEASURED_QUANTITY:
 432                 /* TODO Use std_gvar_measured_quantities() when available. */
 433                 if (!devc)
 434                         return SR_ERR_ARG;
 435                 g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
 436                 for (i = 0; i < devc->model->mqopt_size; i++) {
 437                         arr[0] = g_variant_new_uint32(devc->model->mqopts[i].mq);
 438                         arr[1] = g_variant_new_uint64(devc->model->mqopts[i].mqflag);
 439                         gvar = g_variant_new_tuple(arr, ARRAY_SIZE(arr));
 440                         g_variant_builder_add_value(&gvb, gvar);
 441                 }
 442                 *data = g_variant_builder_end(&gvb);
 443                 return SR_OK;
 444         default:
 445                 (void)devc;
 446                 return SR_ERR_NA;
 447         }
 448 }
 449
 450 static int dev_acquisition_start(const struct sr_dev_inst *sdi)
 451 {
 452         struct sr_scpi_dev_inst *scpi;
 453         struct dev_context *devc;
 454         int ret;
 455         const struct mqopt_item *item;
 456         const char *command;
 457         char *response;
 458
 459         scpi = sdi->conn;
 460         devc = sdi->priv;
 461
 462         ret = scpi_dmm_get_mq(sdi, &devc->start_acq_mq.curr_mq,
 463                 &devc->start_acq_mq.curr_mqflag, NULL, &item);
 464         if (ret != SR_OK)
 465                 return ret;
 466
 467         /*
 468          * Query for current precision if DMM supports the command
 469          */
 470         command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_QUERY_PREC);
 471         if (command && *command) {
 472                 scpi_dmm_cmd_delay(scpi);
 473                 ret = sr_scpi_get_string(scpi, command, &response);
 474                 if (ret == SR_OK) {
 475                         g_strstrip(response);
 476                         g_free(devc->precision);
 477                         devc->precision = g_strdup(response);
 478                         g_free(response);
 479                         sr_dbg("%s: Precision: '%s'", __func__, devc->precision);
 480                 } else {
 481                         sr_info("Precision query ('%s') failed: %d",
 482                                 command, ret);
 483                 }
 484         }
 485
 486         command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_START_ACQ);
 487         if (command && *command) {
 488                 scpi_dmm_cmd_delay(scpi);
 489                 ret = sr_scpi_send(scpi, command);
 490                 if (ret != SR_OK)
 491                         return ret;
 492         }
 493
 494         sr_sw_limits_acquisition_start(&devc->limits);
 495         ret = std_session_send_df_header(sdi);
 496         if (ret != SR_OK)
 497                 return ret;
 498
 499         ret = sr_scpi_source_add(sdi->session, scpi, G_IO_IN, 10,
 500                 scpi_dmm_receive_data, (void *)sdi);
 501         if (ret != SR_OK)
 502                 return ret;
 503
 504         return SR_OK;
 505 }
 506
 507 static int dev_acquisition_stop(struct sr_dev_inst *sdi)
 508 {
 509         struct sr_scpi_dev_inst *scpi;
 510         struct dev_context *devc;
 511         const char *command;
 512
 513         scpi = sdi->conn;
 514         devc = sdi->priv;
 515
 516         command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_STOP_ACQ);
 517         if (command && *command) {
 518                 scpi_dmm_cmd_delay(scpi);
 519                 (void)sr_scpi_send(scpi, command);
 520         }
 521         sr_scpi_source_remove(sdi->session, scpi);
 522
 523         std_session_send_df_end(sdi);
 524
 525         g_free(devc->precision);
 526         devc->precision = NULL;
 527
 528         return SR_OK;
 529 }
 530
 531 static struct sr_dev_driver scpi_dmm_driver_info = {
 532         .name = "scpi-dmm",
 533         .longname = "SCPI DMM",
 534         .api_version = 1,
 535         .init = std_init,
 536         .cleanup = std_cleanup,
 537         .scan = scan,
 538         .dev_list = std_dev_list,
 539         .dev_clear = std_dev_clear,
 540         .config_get = config_get,
 541         .config_set = config_set,
 542         .config_list = config_list,
 543         .dev_open = dev_open,
 544         .dev_close = dev_close,
 545         .dev_acquisition_start = dev_acquisition_start,
 546         .dev_acquisition_stop = dev_acquisition_stop,
 547         .context = NULL,
 548 };
 549 SR_REGISTER_DEV_DRIVER(scpi_dmm_driver_info);