+SR_PRIV int scpi_dmm_get_meas_gwinstek(const struct sr_dev_inst *sdi, size_t ch)
+{
+ struct sr_scpi_dev_inst *scpi;
+ struct dev_context *devc;
+ struct scpi_dmm_acq_info *info;
+ struct sr_datafeed_analog *analog;
+ int ret;
+ enum sr_mq mq;
+ enum sr_mqflag mqflag;
+ char *mode_response;
+ const char *p;
+ const struct mqopt_item *item;
+ const char *command;
+ char *response;
+ gboolean use_double;
+ double limit;
+ int sig_digits, val_exp;
+ int digits;
+ enum sr_unit unit;
+ int mmode;
+
+ scpi = sdi->conn;
+ devc = sdi->priv;
+ info = &devc->run_acq_info;
+ analog = &info->analog[ch];
+
+ /*
+ * Get the meter's current mode, keep the response around.
+ * Skip the measurement if the mode is uncertain.
+ */
+ ret = scpi_dmm_get_mq(sdi, &mq, &mqflag, &mode_response, &item);
+ if (ret != SR_OK) {
+ g_free(mode_response);
+ return ret;
+ }
+ if (!mode_response)
+ return SR_ERR;
+ if (!mq) {
+ g_free(mode_response);
+ return +1;
+ }
+ mmode = atoi(mode_response);
+ g_free(mode_response);
+
+ /*
+ * Get the current reading from the meter.
+ */
+ scpi_dmm_cmd_delay(scpi);
+ command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_QUERY_VALUE);
+ if (!command || !*command)
+ return SR_ERR_NA;
+ scpi_dmm_cmd_delay(scpi);
+ ret = sr_scpi_get_string(scpi, command, &response);
+ if (ret != SR_OK)
+ return ret;
+ g_strstrip(response);
+ use_double = devc->model->digits > 6;
+ ret = sr_atod_ascii(response, &info->d_value);
+ if (ret != SR_OK) {
+ g_free(response);
+ return ret;
+ }
+ if (!response)
+ return SR_ERR;
+ limit = 9e37;
+ if (info->d_value > +limit) {
+ info->d_value = +INFINITY;
+ } else if (info->d_value < -limit) {
+ info->d_value = -INFINITY;
+ } else {
+ p = response;
+ while (p && *p && g_ascii_isspace(*p))
+ p++;
+ if (p && *p && (*p == '-' || *p == '+'))
+ p++;
+ sig_digits = 0;
+ while (p && *p && g_ascii_isdigit(*p)) {
+ sig_digits++;
+ p++;
+ }
+ if (p && *p && *p == '.')
+ p++;
+ while (p && *p && g_ascii_isdigit(*p))
+ p++;
+ ret = SR_OK;
+ if (!p || !*p)
+ val_exp = 0;
+ else if (*p != 'e' && *p != 'E')
+ ret = SR_ERR_DATA;
+ else
+ ret = sr_atoi(++p, &val_exp);
+ }
+ g_free(response);
+ if (ret != SR_OK)
+ return ret;
+
+ /*
+ * Make sure we report "INFINITY" when meter displays "0L".
+ */
+ switch (mmode) {
+ case 7:
+ case 16:
+ /* In resitance modes 0L reads as 1.20000E8 or 1.99999E8. */
+ limit = 1.2e8;
+ if (strcmp(devc->model->model, "GDM8255A") == 0)
+ limit = 1.99999e8;
+ if (info->d_value >= limit)
+ info->d_value = +INFINITY;
+ break;
+ case 13:
+ /* In continuity mode 0L reads as 1.20000E3. */
+ if (info->d_value >= 1.2e3)
+ info->d_value = +INFINITY;
+ break;
+ case 17:
+ /* In diode mode 0L reads as 1.00000E0. */
+ if (info->d_value == 1.0e0)
+ info->d_value = +INFINITY;
+ break;
+ }
+
+ /*
+ * Calculate 'digits' based on the result of the optional
+ * precision reading which was done at acquisition start.
+ * The GW-Instek manual gives the following information
+ * regarding the resolution:
+ *
+ * Type Digit
+ * -------- ------
+ * Slow 5 1/2
+ * Medium 4 1/2
+ * Fast 3 1/2
+ */
+ digits = devc->model->digits;
+ if (devc->precision && *devc->precision) {
+ if (g_str_has_prefix(devc->precision, "Slow"))
+ digits = 6;
+ else if (g_str_has_prefix(devc->precision, "Mid"))
+ digits = 5;
+ else if (g_str_has_prefix(devc->precision, "Fast"))
+ digits = 4;
+ else
+ sr_info("Unknown precision: '%s'", devc->precision);
+ }
+
+ /*
+ * Fill in the 'analog' description: value, encoding, meaning.
+ * Callers will fill in the sample count, and channel name,
+ * and will send out the packet.
+ */
+ if (use_double) {
+ analog->data = &info->d_value;
+ analog->encoding->unitsize = sizeof(info->d_value);
+ } else {
+ info->f_value = info->d_value;
+ analog->data = &info->f_value;
+ analog->encoding->unitsize = sizeof(info->f_value);
+ }
+ analog->encoding->digits = digits;
+ analog->meaning->mq = mq;
+ analog->meaning->mqflags = mqflag;
+ switch (mq) {
+ case SR_MQ_VOLTAGE:
+ unit = SR_UNIT_VOLT;
+ break;
+ case SR_MQ_CURRENT:
+ unit = SR_UNIT_AMPERE;
+ break;
+ case SR_MQ_RESISTANCE:
+ case SR_MQ_CONTINUITY:
+ unit = SR_UNIT_OHM;
+ break;
+ case SR_MQ_CAPACITANCE:
+ unit = SR_UNIT_FARAD;
+ break;
+ case SR_MQ_TEMPERATURE:
+ switch (mmode) {
+ case 15:
+ unit = SR_UNIT_FAHRENHEIT;
+ break;
+ case 9:
+ default:
+ unit = SR_UNIT_CELSIUS;
+ }
+ break;
+ case SR_MQ_FREQUENCY:
+ unit = SR_UNIT_HERTZ;
+ break;
+ case SR_MQ_TIME:
+ unit = SR_UNIT_SECOND;
+ break;
+ default:
+ return SR_ERR_NA;
+ }
+ analog->meaning->unit = unit;
+ analog->spec->spec_digits = digits;
+
+ return SR_OK;
+}
+