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