lib: Add GPIO version of the bias tee configuration API

rtl_biast allows for non-default GPIO pins to be used.
Add an API call which allows for that.

2 files changed, 19 insertions, 3 deletions

diff --git a/include/rtl-sdr.h b/include/rtl-sdr.h
index 3ed13ae..d64701e 100644
--- a/include/rtl-sdr.h
+++ b/include/rtl-sdr.h
@@ -389,6 +389,17 @@ RTLSDR_API int rtlsdr_cancel_async(rtlsdr_dev_t *dev);
  */
 RTLSDR_API int rtlsdr_set_bias_tee(rtlsdr_dev_t *dev, int on);
 
+/*!
+ * Enable or disable the bias tee on the given GPIO pin.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param gpio the gpio pin to configure as a Bias T control.
+ * \param on  1 for Bias T on. 0 for Bias T off.
+ * \return -1 if device is not initialized. 0 otherwise.
+ */
+RTLSDR_API int rtlsdr_set_bias_tee_gpio(rtlsdr_dev_t *dev, int gpio, int on);
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/librtlsdr.c b/src/librtlsdr.c
index 213e96c..0146298 100644
--- a/src/librtlsdr.c
+++ b/src/librtlsdr.c
@@ -2009,13 +2009,18 @@ int rtlsdr_i2c_read_fn(void *dev, uint8_t addr, uint8_t *buf, int len)
 	return -1;
 }
 
-int rtlsdr_set_bias_tee(rtlsdr_dev_t *dev, int on)
+int rtlsdr_set_bias_tee_gpio(rtlsdr_dev_t *dev, int gpio, int on)
 {
 	if (!dev)
 		return -1;
 
-	rtlsdr_set_gpio_output(dev, 0);
-	rtlsdr_set_gpio_bit(dev, 0, on);
+	rtlsdr_set_gpio_output(dev, gpio);
+	rtlsdr_set_gpio_bit(dev, gpio, on);
 
 	return 0;
 }
+
+int rtlsdr_set_bias_tee(rtlsdr_dev_t *dev, int on)
+{
+	return rtlsdr_set_bias_tee_gpio(dev, 0, on);
+}