SR_MHZ(200), /* Special FW needed */
};
-SR_PRIV const int SAMPLERATES_COUNT = ARRAY_SIZE(samplerates);
+SR_PRIV const size_t samplerates_count = ARRAY_SIZE(samplerates);
static const char sigma_firmware_files[][24] = {
/* 50 MHz, supports 8 bit fractions */
uint8_t buf[80];
int idx = 0;
- if ((len + 2) > sizeof(buf)) {
+ if ((2 * len + 2) > sizeof(buf)) {
sr_err("Attempted to write %zu bytes, but buffer is too small.",
- len + 2);
+ len);
return SR_ERR_BUG;
}
{
struct dev_context *devc;
struct drv_context *drvc;
- unsigned int i;
+ size_t i;
int ret;
devc = sdi->priv;
drvc = sdi->driver->context;
ret = SR_OK;
- for (i = 0; i < ARRAY_SIZE(samplerates); i++) {
+ /* Reject rates that are not in the list of supported rates. */
+ for (i = 0; i < samplerates_count; i++) {
if (samplerates[i] == samplerate)
break;
}
- if (samplerates[i] == 0)
+ 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;
}