apply steve-m/librtlsdr/pull/64 (bias-t only)

.gitignore

@@ -39,3 +39,7 @@ CMakeCache.txt
 */CMakeFiles
 CMakeFiles
 *.cmake
+
+build/
+cmake-build-*
+

include/rtl-sdr.h

@@ -397,7 +397,14 @@ RTLSDR_API int rtlsdr_set_bias_tee(rtlsdr_dev_t *dev, int on);
  */
 RTLSDR_API int rtlsdr_set_gpio(rtlsdr_dev_t *dev, int gpio_pin, int on);
 
-
+/*!
+ * Control whether the bias tee is left on after rtlsdr_close() is called.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param leave_on 1 to leave Bias T on upon library close; 0 otherwise
+ * \return -1 if device is not initialized. 0 otherwise.
+ */
+RTLSDR_API int rtlsdr_set_bias_tee_leave_on(rtlsdr_dev_t *dev, int leave_on);
 
 #ifdef __cplusplus
 }

src/librtlsdr.c

@@ -104,6 +104,8 @@ struct rtlsdr_dev {
 	enum rtlsdr_async_status async_status;
 	int async_cancel;
 	int use_zerocopy;
+	int keep_biast_on;
+	int biast_gpio;
 	/* rtl demod context */
 	uint32_t rate; /* Hz */
 	uint32_t rtl_xtal; /* Hz */
@@ -1686,6 +1688,14 @@ int rtlsdr_close(rtlsdr_dev_t *dev)
 		rtlsdr_deinit_baseband(dev);
 	}
 
+	/*
+	 * Disable bias-tee unless we're explicitly asked
+	 * to keep it on.
+	 */
+	if (dev->keep_biast_on == 0) {
+		rtlsdr_set_bias_tee(dev, 0);
+	}
+
 	libusb_release_interface(dev->devh, 0);
 
 #ifdef DETACH_KERNEL_DRIVER
@@ -2060,8 +2070,12 @@ int rtlsdr_set_bias_tee(rtlsdr_dev_t *dev, int on)
 	if (!dev)
 		return -1;
 
-	if(dev->force_bt) on = 1; // If force_bt is on from the EEPROM, do not allow bias tee to turn off
+	if(dev->force_bt) {
+		on = 1; // If force_bt is on from the EEPROM, do not allow bias tee to turn off
+		dev->keep_biast_on = 1;
+	}
 
+	dev->biast_gpio = 0; // always 0?
 	rtlsdr_set_gpio_output(dev, 0);
 	rtlsdr_set_gpio_bit(dev, 0, on);
 
@@ -2080,3 +2094,12 @@ int rtlsdr_set_gpio(rtlsdr_dev_t *dev, int gpio_pin, int on)
 
 	return 1;
 }
+
+int rtlsdr_set_bias_tee_leave_on(rtlsdr_dev_t *dev, int leave_on)
+{
+	if (!dev)
+		return -1;
+
+	dev->keep_biast_on = leave_on;
+	return 0;
+}

src/rtl_biast.c

@@ -112,7 +112,10 @@ int main(int argc, char **argv)
 
 	r = rtlsdr_open(&dev, dev_index);
 
+	//dev->biast_gpio = gpio_pin;
 	rtlsdr_set_gpio(dev, gpio_pin, bias_on);
+	rtlsdr_set_bias_tee_leave_on(dev, 1);
+
 	//rtlsdr_set_bias_tee(dev, bias_on);
 
 	//rtlsdr_set_direct_sampling(dev, 1);