drvc = sdi->driver->context;
ret = SR_OK;
+ /* Reject rates that are not in the list of supported rates. */
for (i = 0; i < samplerates_count; i++) {
if (samplerates[i] == samplerate)
break;
if (i >= samplerates_count || samplerates[i] == 0)
return SR_ERR_SAMPLERATE;
+ /*
+ * Depending on the samplerates of 200/100/50- MHz, specific
+ * firmware is required and higher rates might limit the set
+ * of available channels.
+ */
if (samplerate <= SR_MHZ(50)) {
ret = upload_firmware(drvc->sr_ctx, 0, devc);
devc->num_channels = 16;
devc->num_channels = 4;
}
+ /*
+ * Derive the sample period from the sample rate as well as the
+ * number of samples that the device will communicate within
+ * an "event" (memory organization internal to the device).
+ */
if (ret == SR_OK) {
devc->cur_samplerate = samplerate;
devc->period_ps = 1000000000000ULL / samplerate;
devc->state.state = SIGMA_IDLE;
}
+ /*
+ * Support for "limit_samples" is implemented by stopping
+ * acquisition after a corresponding period of time.
+ * Re-calculate that period of time, in case the limit is
+ * set first and the samplerate gets (re-)configured later.
+ */
+ if (ret == SR_OK && devc->limit_samples) {
+ uint64_t msecs;
+ msecs = devc->limit_samples * 1000 / devc->cur_samplerate;
+ devc->limit_msec = msecs;
+ }
+
return ret;
}