src/hardware/scpi-pps/api.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 <strings.h>
  22 #include "protocol.h"
  23
  24 SR_PRIV struct sr_dev_driver scpi_pps_driver_info;
  25 extern unsigned int num_pps_profiles;
  26 extern const struct scpi_pps pps_profiles[];
  27
  28 static const uint32_t scanopts[] = {
  29         SR_CONF_CONN,
  30         SR_CONF_SERIALCOMM,
  31 };
  32
  33 static const uint32_t drvopts[] = {
  34         SR_CONF_POWER_SUPPLY,
  35 };
  36
  37 static const struct pps_channel_instance pci[] = {
  38         { SR_MQ_VOLTAGE, SCPI_CMD_GET_MEAS_VOLTAGE, "V" },
  39         { SR_MQ_CURRENT, SCPI_CMD_GET_MEAS_CURRENT, "I" },
  40         { SR_MQ_POWER, SCPI_CMD_GET_MEAS_POWER, "P" },
  41         { SR_MQ_FREQUENCY, SCPI_CMD_GET_MEAS_FREQUENCY, "F" },
  42 };
  43
  44 static int init(struct sr_dev_driver *di, struct sr_context *sr_ctx)
  45 {
  46         return std_init(sr_ctx, di, LOG_PREFIX);
  47 }
  48
  49 static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
  50 {
  51         struct dev_context *devc;
  52         struct sr_dev_inst *sdi;
  53         struct sr_scpi_hw_info *hw_info;
  54         struct sr_channel_group *cg;
  55         struct sr_channel *ch;
  56         const struct scpi_pps *device;
  57         struct pps_channel *pch;
  58         struct channel_spec *channels;
  59         struct channel_group_spec *channel_groups, *cgs;
  60         struct pps_channel_group *pcg;
  61         GRegex *model_re;
  62         GMatchInfo *model_mi;
  63         GSList *l;
  64         uint64_t mask;
  65         unsigned int num_channels, num_channel_groups, ch_num, ch_idx, i, j;
  66         int ret;
  67         const char *vendor;
  68         char ch_name[16];
  69
  70         if (sr_scpi_get_hw_id(scpi, &hw_info) != SR_OK) {
  71                 sr_info("Couldn't get IDN response.");
  72                 return NULL;
  73         }
  74
  75         device = NULL;
  76         for (i = 0; i < num_pps_profiles; i++) {
  77                 vendor = get_vendor(hw_info->manufacturer);
  78                 if (strcasecmp(vendor, pps_profiles[i].vendor))
  79                         continue;
  80                 model_re = g_regex_new(pps_profiles[i].model, 0, 0, NULL);
  81                 if (g_regex_match(model_re, hw_info->model, 0, &model_mi))
  82                         device = &pps_profiles[i];
  83                 g_match_info_unref(model_mi);
  84                 g_regex_unref(model_re);
  85                 if (device)
  86                         break;
  87         }
  88         if (!device) {
  89                 sr_scpi_hw_info_free(hw_info);
  90                 return NULL;
  91         }
  92
  93         sdi = g_malloc0(sizeof(struct sr_dev_inst));
  94         sdi->status = SR_ST_INACTIVE;
  95         sdi->vendor = g_strdup(vendor);
  96         sdi->model = g_strdup(hw_info->model);
  97         sdi->version = g_strdup(hw_info->firmware_version);
  98         sdi->conn = scpi;
  99         sdi->driver = &scpi_pps_driver_info;
 100         sdi->inst_type = SR_INST_SCPI;
 101         sdi->serial_num = g_strdup(hw_info->serial_number);
 102
 103         devc = g_malloc0(sizeof(struct dev_context));
 104         devc->device = device;
 105         sdi->priv = devc;
 106
 107         if (device->num_channels) {
 108                 /* Static channels and groups. */
 109                 channels = (struct channel_spec *)device->channels;
 110                 num_channels = device->num_channels;
 111                 channel_groups = (struct channel_group_spec *)device->channel_groups;
 112                 num_channel_groups = device->num_channel_groups;
 113         } else {
 114                 /* Channels and groups need to be probed. */
 115                 ret = device->probe_channels(sdi, hw_info, &channels, &num_channels,
 116                                 &channel_groups, &num_channel_groups);
 117                 if (ret != SR_OK) {
 118                         sr_err("Failed to probe for channels.");
 119                         return NULL;
 120                 }
 121                 /*
 122                  * Since these were dynamically allocated, we'll need to free them
 123                  * later.
 124                  */
 125                 devc->channels = channels;
 126                 devc->channel_groups = channel_groups;
 127         }
 128
 129         ch_idx = 0;
 130         for (ch_num = 0; ch_num < num_channels; ch_num++) {
 131                 /* Create one channel per measurable output unit. */
 132                 for (i = 0; i < ARRAY_SIZE(pci); i++) {
 133                         if (!scpi_cmd_get(sdi, pci[i].command))
 134                                 continue;
 135                         g_snprintf(ch_name, 16, "%s%s", pci[i].prefix,
 136                                         channels[ch_num].name);
 137                         ch = sr_channel_new(sdi, ch_idx++, SR_CHANNEL_ANALOG, TRUE,
 138                                         ch_name);
 139                         pch = g_malloc0(sizeof(struct pps_channel));
 140                         pch->hw_output_idx = ch_num;
 141                         pch->hwname = channels[ch_num].name;
 142                         pch->mq = pci[i].mq;
 143                         ch->priv = pch;
 144                 }
 145         }
 146
 147         for (i = 0; i < num_channel_groups; i++) {
 148                 cgs = &channel_groups[i];
 149                 cg = g_malloc0(sizeof(struct sr_channel_group));
 150                 cg->name = g_strdup(cgs->name);
 151                 for (j = 0, mask = 1; j < 64; j++, mask <<= 1) {
 152                         if (cgs->channel_index_mask & mask) {
 153                                 for (l = sdi->channels; l; l = l->next) {
 154                                         ch = l->data;
 155                                         pch = ch->priv;
 156                                         if (pch->hw_output_idx == j)
 157                                                 cg->channels = g_slist_append(cg->channels, ch);
 158                                 }
 159                         }
 160                 }
 161                 pcg = g_malloc0(sizeof(struct pps_channel_group));
 162                 pcg->features = cgs->features;
 163                 cg->priv = pcg;
 164                 sdi->channel_groups = g_slist_append(sdi->channel_groups, cg);
 165         }
 166
 167         sr_scpi_hw_info_free(hw_info);
 168         hw_info = NULL;
 169
 170         scpi_cmd(sdi, SCPI_CMD_LOCAL);
 171         sr_scpi_close(scpi);
 172
 173         return sdi;
 174 }
 175
 176 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 177 {
 178         return sr_scpi_scan(di->priv, options, probe_device);
 179 }
 180
 181 static GSList *dev_list(const struct sr_dev_driver *di)
 182 {
 183         return ((struct drv_context *)(di->priv))->instances;
 184 }
 185
 186 static int dev_clear(const struct sr_dev_driver *di)
 187 {
 188         return std_dev_clear(di, NULL);
 189 }
 190
 191 static int dev_open(struct sr_dev_inst *sdi)
 192 {
 193         struct dev_context *devc;
 194         struct sr_scpi_dev_inst *scpi;
 195         GVariant *beeper;
 196
 197         if (sdi->status != SR_ST_INACTIVE)
 198                 return SR_ERR;
 199
 200         scpi = sdi->conn;
 201         if (sr_scpi_open(scpi) < 0)
 202                 return SR_ERR;
 203
 204         sdi->status = SR_ST_ACTIVE;
 205
 206         scpi_cmd(sdi, SCPI_CMD_REMOTE);
 207         devc = sdi->priv;
 208         devc->beeper_was_set = FALSE;
 209         if (scpi_cmd_resp(sdi, &beeper, G_VARIANT_TYPE_BOOLEAN, SCPI_CMD_BEEPER) == SR_OK) {
 210                 if (g_variant_get_boolean(beeper)) {
 211                         devc->beeper_was_set = TRUE;
 212                         scpi_cmd(sdi, SCPI_CMD_BEEPER_DISABLE);
 213                 }
 214                 g_variant_unref(beeper);
 215         }
 216
 217         return SR_OK;
 218 }
 219
 220 static int dev_close(struct sr_dev_inst *sdi)
 221 {
 222         struct sr_scpi_dev_inst *scpi;
 223         struct dev_context *devc;
 224
 225         if (sdi->status != SR_ST_ACTIVE)
 226                 return SR_ERR_DEV_CLOSED;
 227
 228         devc = sdi->priv;
 229         scpi = sdi->conn;
 230         if (scpi) {
 231                 if (devc->beeper_was_set)
 232                         scpi_cmd(sdi, SCPI_CMD_BEEPER_ENABLE);
 233                 scpi_cmd(sdi, SCPI_CMD_LOCAL);
 234                 sr_scpi_close(scpi);
 235                 sdi->status = SR_ST_INACTIVE;
 236         }
 237
 238         return SR_OK;
 239 }
 240
 241 static void clear_helper(void *priv)
 242 {
 243         struct dev_context *devc;
 244
 245         devc = priv;
 246         g_free(devc->channels);
 247         g_free(devc->channel_groups);
 248         g_free(devc);
 249 }
 250
 251 static int cleanup(const struct sr_dev_driver *di)
 252 {
 253         return std_dev_clear(di, clear_helper);
 254 }
 255
 256 static int config_get(uint32_t key, GVariant **data, const struct sr_dev_inst *sdi,
 257                 const struct sr_channel_group *cg)
 258 {
 259         struct dev_context *devc;
 260         const GVariantType *gvtype;
 261         unsigned int i;
 262         int cmd, ret;
 263
 264         if (!sdi)
 265                 return SR_ERR_ARG;
 266
 267         devc = sdi->priv;
 268
 269         if (cg) {
 270                 /*
 271                  * These options only apply to channel groups with a single
 272                  * channel -- they're per-channel settings for the device.
 273                  */
 274
 275                 /*
 276                  * Config keys are handled below depending on whether a channel
 277                  * group was provided by the frontend. However some of these
 278                  * take a CG on one PPS but not on others. Check the device's
 279                  * profile for that here, and NULL out the channel group as needed.
 280                  */
 281                 for (i = 0; i < devc->device->num_devopts; i++) {
 282                         if (devc->device->devopts[i] == key) {
 283                                 cg = NULL;
 284                                 break;
 285                         }
 286                 }
 287         }
 288
 289         gvtype = NULL;
 290         cmd = -1;
 291         switch (key) {
 292         case SR_CONF_OUTPUT_ENABLED:
 293                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 294                 cmd = SCPI_CMD_GET_OUTPUT_ENABLED;
 295                 break;
 296         case SR_CONF_OUTPUT_VOLTAGE:
 297                 gvtype = G_VARIANT_TYPE_DOUBLE;
 298                 cmd = SCPI_CMD_GET_MEAS_VOLTAGE;
 299                 break;
 300         case SR_CONF_OUTPUT_VOLTAGE_TARGET:
 301                 gvtype = G_VARIANT_TYPE_DOUBLE;
 302                 cmd = SCPI_CMD_GET_VOLTAGE_TARGET;
 303                 break;
 304         case SR_CONF_OUTPUT_FREQUENCY:
 305                 gvtype = G_VARIANT_TYPE_DOUBLE;
 306                 cmd = SCPI_CMD_GET_MEAS_FREQUENCY;
 307                 break;
 308         case SR_CONF_OUTPUT_FREQUENCY_TARGET:
 309                 gvtype = G_VARIANT_TYPE_DOUBLE;
 310                 cmd = SCPI_CMD_GET_FREQUENCY_TARGET;
 311                 break;
 312         case SR_CONF_OUTPUT_CURRENT:
 313                 gvtype = G_VARIANT_TYPE_DOUBLE;
 314                 cmd = SCPI_CMD_GET_MEAS_CURRENT;
 315                 break;
 316         case SR_CONF_OUTPUT_CURRENT_LIMIT:
 317                 gvtype = G_VARIANT_TYPE_DOUBLE;
 318                 cmd = SCPI_CMD_GET_CURRENT_LIMIT;
 319                 break;
 320         case SR_CONF_OVER_VOLTAGE_PROTECTION_ENABLED:
 321                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 322                 cmd = SCPI_CMD_GET_OVER_VOLTAGE_PROTECTION_ENABLED;
 323                 break;
 324         case SR_CONF_OVER_VOLTAGE_PROTECTION_ACTIVE:
 325                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 326                 cmd = SCPI_CMD_GET_OVER_VOLTAGE_PROTECTION_ACTIVE;
 327                 break;
 328         case SR_CONF_OVER_VOLTAGE_PROTECTION_THRESHOLD:
 329                 gvtype = G_VARIANT_TYPE_DOUBLE;
 330                 cmd = SCPI_CMD_GET_OVER_VOLTAGE_PROTECTION_THRESHOLD;
 331                 break;
 332         case SR_CONF_OVER_CURRENT_PROTECTION_ENABLED:
 333                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 334                 cmd = SCPI_CMD_GET_OVER_CURRENT_PROTECTION_ENABLED;
 335                 break;
 336         case SR_CONF_OVER_CURRENT_PROTECTION_ACTIVE:
 337                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 338                 cmd = SCPI_CMD_GET_OVER_CURRENT_PROTECTION_ACTIVE;
 339                 break;
 340         case SR_CONF_OVER_CURRENT_PROTECTION_THRESHOLD:
 341                 gvtype = G_VARIANT_TYPE_DOUBLE;
 342                 cmd = SCPI_CMD_GET_OVER_CURRENT_PROTECTION_THRESHOLD;
 343                 break;
 344         case SR_CONF_OVER_TEMPERATURE_PROTECTION:
 345                 gvtype = G_VARIANT_TYPE_BOOLEAN;
 346                 cmd = SCPI_CMD_GET_OVER_TEMPERATURE_PROTECTION;
 347                 break;
 348         case SR_CONF_OUTPUT_REGULATION:
 349                 gvtype = G_VARIANT_TYPE_STRING;
 350                 cmd = SCPI_CMD_GET_OUTPUT_REGULATION;
 351         }
 352         if (gvtype) {
 353                 if (cg)
 354                         select_channel(sdi, cg->channels->data);
 355                 ret = scpi_cmd_resp(sdi, data, gvtype, cmd);
 356         } else
 357                 ret = SR_ERR_NA;
 358
 359         return ret;
 360 }
 361
 362 static int config_set(uint32_t key, GVariant *data, const struct sr_dev_inst *sdi,
 363                 const struct sr_channel_group *cg)
 364 {
 365         double d;
 366         int ret;
 367
 368         if (!sdi)
 369                 return SR_ERR_ARG;
 370
 371         if (sdi->status != SR_ST_ACTIVE)
 372                 return SR_ERR_DEV_CLOSED;
 373
 374         if (cg)
 375                 /* Channel group specified. */
 376                 select_channel(sdi, cg->channels->data);
 377
 378         ret = SR_OK;
 379         switch (key) {
 380         case SR_CONF_OUTPUT_ENABLED:
 381                 if (g_variant_get_boolean(data))
 382                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OUTPUT_ENABLE);
 383                 else
 384                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OUTPUT_DISABLE);
 385                 break;
 386         case SR_CONF_OUTPUT_VOLTAGE_TARGET:
 387                 d = g_variant_get_double(data);
 388                 ret = scpi_cmd(sdi, SCPI_CMD_SET_VOLTAGE_TARGET, d);
 389                 break;
 390         case SR_CONF_OUTPUT_FREQUENCY_TARGET:
 391                 d = g_variant_get_double(data);
 392                 ret = scpi_cmd(sdi, SCPI_CMD_SET_FREQUENCY_TARGET, d);
 393                 break;
 394         case SR_CONF_OUTPUT_CURRENT_LIMIT:
 395                 d = g_variant_get_double(data);
 396                 ret = scpi_cmd(sdi, SCPI_CMD_SET_CURRENT_LIMIT, d);
 397                 break;
 398         case SR_CONF_OVER_VOLTAGE_PROTECTION_ENABLED:
 399                 if (g_variant_get_boolean(data))
 400                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_VOLTAGE_PROTECTION_ENABLE);
 401                 else
 402                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_VOLTAGE_PROTECTION_DISABLE);
 403                 break;
 404         case SR_CONF_OVER_VOLTAGE_PROTECTION_THRESHOLD:
 405                 d = g_variant_get_double(data);
 406                 ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_VOLTAGE_PROTECTION_THRESHOLD, d);
 407                 break;
 408         case SR_CONF_OVER_CURRENT_PROTECTION_ENABLED:
 409                 if (g_variant_get_boolean(data))
 410                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_CURRENT_PROTECTION_ENABLE);
 411                 else
 412                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_CURRENT_PROTECTION_DISABLE);
 413                 break;
 414         case SR_CONF_OVER_CURRENT_PROTECTION_THRESHOLD:
 415                 d = g_variant_get_double(data);
 416                 ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_CURRENT_PROTECTION_THRESHOLD, d);
 417                 break;
 418         case SR_CONF_OVER_TEMPERATURE_PROTECTION:
 419                 if (g_variant_get_boolean(data))
 420                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_TEMPERATURE_PROTECTION_ENABLE);
 421                 else
 422                         ret = scpi_cmd(sdi, SCPI_CMD_SET_OVER_TEMPERATURE_PROTECTION_DISABLE);
 423                 break;
 424         default:
 425                 ret = SR_ERR_NA;
 426         }
 427
 428         return ret;
 429 }
 430
 431 static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *sdi,
 432                 const struct sr_channel_group *cg)
 433 {
 434         struct dev_context *devc;
 435         struct sr_channel *ch;
 436         const struct channel_spec *ch_spec;
 437         GVariant *gvar;
 438         GVariantBuilder gvb;
 439         int ret, i;
 440         const char *s[16];
 441
 442         /* Always available, even without sdi. */
 443         if (key == SR_CONF_SCAN_OPTIONS) {
 444                 *data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
 445                                 scanopts, ARRAY_SIZE(scanopts), sizeof(uint32_t));
 446                 return SR_OK;
 447         } else if (key == SR_CONF_DEVICE_OPTIONS && !sdi) {
 448                 *data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
 449                                 drvopts, ARRAY_SIZE(drvopts), sizeof(uint32_t));
 450                 return SR_OK;
 451         }
 452
 453         if (!sdi)
 454                 return SR_ERR_ARG;
 455         devc = sdi->priv;
 456
 457         ret = SR_OK;
 458         if (!cg) {
 459                 /* No channel group: global options. */
 460                 switch (key) {
 461                 case SR_CONF_DEVICE_OPTIONS:
 462                         *data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
 463                                         devc->device->devopts, devc->device->num_devopts,
 464                                         sizeof(uint32_t));
 465                         break;
 466                 case SR_CONF_OUTPUT_CHANNEL_CONFIG:
 467                         /* Not used. */
 468                         i = 0;
 469                         if (devc->device->features & PPS_INDEPENDENT)
 470                                 s[i++] = "Independent";
 471                         if (devc->device->features & PPS_SERIES)
 472                                 s[i++] = "Series";
 473                         if (devc->device->features & PPS_PARALLEL)
 474                                 s[i++] = "Parallel";
 475                         if (i == 0) {
 476                                 /*
 477                                  * Shouldn't happen: independent-only devices
 478                                  * shouldn't advertise this option at all.
 479                                  */
 480                                 return SR_ERR_NA;
 481                         }
 482                         *data = g_variant_new_strv(s, i);
 483                         break;
 484                 default:
 485                         return SR_ERR_NA;
 486                 }
 487         } else {
 488                 /* Channel group specified. */
 489                 /*
 490                  * Per-channel-group options depending on a channel are actually
 491                  * done with the first channel. Channel groups in PPS can have
 492                  * more than one channel, but they will typically be of equal
 493                  * specification for use in series or parallel mode.
 494                  */
 495                 ch = cg->channels->data;
 496
 497                 switch (key) {
 498                 case SR_CONF_DEVICE_OPTIONS:
 499                         *data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
 500                                         devc->device->devopts_cg, devc->device->num_devopts_cg,
 501                                         sizeof(uint32_t));
 502                         break;
 503                 case SR_CONF_OUTPUT_VOLTAGE_TARGET:
 504                         ch_spec = &(devc->device->channels[ch->index]);
 505                         g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
 506                         /* Min, max, write resolution. */
 507                         for (i = 0; i < 3; i++) {
 508                                 gvar = g_variant_new_double(ch_spec->voltage[i]);
 509                                 g_variant_builder_add_value(&gvb, gvar);
 510                         }
 511                         *data = g_variant_builder_end(&gvb);
 512                         break;
 513                 case SR_CONF_OUTPUT_FREQUENCY_TARGET:
 514                         ch_spec = &(devc->device->channels[ch->index]);
 515                         g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
 516                         /* Min, max, write resolution. */
 517                         for (i = 0; i < 3; i++) {
 518                                 gvar = g_variant_new_double(ch_spec->frequency[i]);
 519                                 g_variant_builder_add_value(&gvb, gvar);
 520                         }
 521                         *data = g_variant_builder_end(&gvb);
 522                         break;
 523                 case SR_CONF_OUTPUT_CURRENT_LIMIT:
 524                         g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
 525                         /* Min, max, step. */
 526                         for (i = 0; i < 3; i++) {
 527                                 ch_spec = &(devc->device->channels[ch->index]);
 528                                 gvar = g_variant_new_double(ch_spec->current[i]);
 529                                 g_variant_builder_add_value(&gvb, gvar);
 530                         }
 531                         *data = g_variant_builder_end(&gvb);
 532                         break;
 533                 default:
 534                         return SR_ERR_NA;
 535                 }
 536         }
 537
 538         return ret;
 539 }
 540
 541 static int dev_acquisition_start(const struct sr_dev_inst *sdi,
 542                 void *cb_data)
 543 {
 544         struct dev_context *devc;
 545         struct sr_scpi_dev_inst *scpi;
 546         struct sr_channel *ch;
 547         struct pps_channel *pch;
 548         int cmd, ret;
 549
 550         if (sdi->status != SR_ST_ACTIVE)
 551                 return SR_ERR_DEV_CLOSED;
 552
 553         devc = sdi->priv;
 554         scpi = sdi->conn;
 555         devc->cb_data = cb_data;
 556
 557         if ((ret = sr_scpi_source_add(sdi->session, scpi, G_IO_IN, 10,
 558                         scpi_pps_receive_data, (void *)sdi)) != SR_OK)
 559                 return ret;
 560         std_session_send_df_header(sdi, LOG_PREFIX);
 561
 562         /* Prime the pipe with the first channel's fetch. */
 563         ch = next_enabled_channel(sdi, NULL);
 564         pch = ch->priv;
 565         if ((ret = select_channel(sdi, ch)) != SR_OK)
 566                 return ret;
 567         if (pch->mq == SR_MQ_VOLTAGE)
 568                 cmd = SCPI_CMD_GET_MEAS_VOLTAGE;
 569         else if (pch->mq == SR_MQ_FREQUENCY)
 570                 cmd = SCPI_CMD_GET_MEAS_FREQUENCY;
 571         else if (pch->mq == SR_MQ_CURRENT)
 572                 cmd = SCPI_CMD_GET_MEAS_CURRENT;
 573         else if (pch->mq == SR_MQ_POWER)
 574                 cmd = SCPI_CMD_GET_MEAS_POWER;
 575         else
 576                 return SR_ERR;
 577         scpi_cmd(sdi, cmd, pch->hwname);
 578
 579         return SR_OK;
 580 }
 581
 582 static int dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
 583 {
 584         struct sr_datafeed_packet packet;
 585         struct sr_scpi_dev_inst *scpi;
 586         float f;
 587
 588         (void)cb_data;
 589
 590         if (sdi->status != SR_ST_ACTIVE)
 591                 return SR_ERR_DEV_CLOSED;
 592
 593         scpi = sdi->conn;
 594
 595         /*
 596          * A requested value is certainly on the way. Retrieve it now,
 597          * to avoid leaving the device in a state where it's not expecting
 598          * commands.
 599          */
 600         sr_scpi_get_float(scpi, NULL, &f);
 601         sr_scpi_source_remove(sdi->session, scpi);
 602
 603         packet.type = SR_DF_END;
 604         sr_session_send(sdi, &packet);
 605
 606         return SR_OK;
 607 }
 608
 609 SR_PRIV struct sr_dev_driver scpi_pps_driver_info = {
 610         .name = "scpi-pps",
 611         .longname = "SCPI PPS",
 612         .api_version = 1,
 613         .init = init,
 614         .cleanup = cleanup,
 615         .scan = scan,
 616         .dev_list = dev_list,
 617         .dev_clear = dev_clear,
 618         .config_get = config_get,
 619         .config_set = config_set,
 620         .config_list = config_list,
 621         .dev_open = dev_open,
 622         .dev_close = dev_close,
 623         .dev_acquisition_start = dev_acquisition_start,
 624         .dev_acquisition_stop = dev_acquisition_stop,
 625         .priv = NULL,
 626 };