add getters for direct sampling and offset tuning mode

Signed-off-by: Steve Markgraf <steve@steve-m.de>

include/rtl-sdr.h

@@ -241,6 +241,15 @@ RTLSDR_API int rtlsdr_set_agc_mode(rtlsdr_dev_t *dev, int on);
  */
 RTLSDR_API int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on);
 
+/*!
+ * Get state of the direct sampling mode
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return -1 on error, 0 means disabled, 1 I-ADC input enabled
+ *	    2 Q-ADC input enabled
+ */
+RTLSDR_API int rtlsdr_get_direct_sampling(rtlsdr_dev_t *dev);
+
 /*!
  * Enable or disable offset tuning for zero-IF tuners, which allows to avoid
  * problems caused by the DC offset of the ADCs and 1/f noise.
@@ -251,6 +260,14 @@ RTLSDR_API int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on);
  */
 RTLSDR_API int rtlsdr_set_offset_tuning(rtlsdr_dev_t *dev, int on);
 
+/*!
+ * Get state of the offset tuning mode
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return -1 on error, 0 means disabled, 1 enabled
+ */
+RTLSDR_API int rtlsdr_get_offset_tuning(rtlsdr_dev_t *dev);
+
 /* streaming functions */
 
 RTLSDR_API int rtlsdr_reset_buffer(rtlsdr_dev_t *dev);

src/librtlsdr.c

@@ -1020,6 +1020,14 @@ int rtlsdr_set_direct_sampling(rtlsdr_dev_t *dev, int on)
 	return r;
 }
 
+int rtlsdr_get_direct_sampling(rtlsdr_dev_t *dev)
+{
+	if (!dev)
+		return -1;
+
+	return dev->direct_sampling;
+}
+
 int rtlsdr_set_offset_tuning(rtlsdr_dev_t *dev, int on)
 {
 	int r = 0;
@@ -1030,6 +1038,9 @@ int rtlsdr_set_offset_tuning(rtlsdr_dev_t *dev, int on)
 	if (dev->tuner_type == RTLSDR_TUNER_R820T)
 		return -2;
 
+	if (dev->direct_sampling)
+		return -3;
+
 	/* based on keenerds 1/f noise measurements */
 	dev->offs_freq = on ? ((dev->rate / 2) * 170 / 100) : 0;
 	r |= rtlsdr_set_if_freq(dev, dev->offs_freq);
@@ -1045,6 +1056,14 @@ int rtlsdr_set_offset_tuning(rtlsdr_dev_t *dev, int on)
 	return r;
 }
 
+int rtlsdr_get_offset_tuning(rtlsdr_dev_t *dev)
+{
+	if (!dev)
+		return -1;
+
+	return (dev->offs_freq) ? 1 : 0;
+}
+
 static rtlsdr_dongle_t *find_known_device(uint16_t vid, uint16_t pid)
 {
 	unsigned int i;