binding: radio: update build system for standalone binding

Radio binding is now standalone so the qmake build scripts need
to be updated to reflect that

Bug-AGL: SPEC-832
Change-Id: Iab9cd5d18536e416d22d91c492ef489159a62d0d
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>

12 files changed, 2949 insertions, 0 deletions

diff --git a/binding/binding.pri b/binding/binding.pri
new file mode 100644
index 0000000..3448a56
--- /dev/null
+++ b/binding/binding.pri
@@ -0,0 +1,6 @@
+TEMPLATE = lib
+CONFIG += plugin use_c_linker
+CONFIG -= qt
+QMAKE_CFLAGS += -Wextra -Wconversion -Wno-unused-parameter -Werror=maybe-uninitialized -Werror=implicit-function-declaration -ffunction-sections -fdata-sections -Wl,--as-needed -Wl,--gc-sections
+
+DESTDIR = $${OUT_PWD}/../package/root/lib
diff --git a/binding/binding.pro b/binding/binding.pro
new file mode 100644
index 0000000..d8c5a93
--- /dev/null
+++ b/binding/binding.pro
@@ -0,0 +1,11 @@
+TARGET = radio-binding
+
+HEADERS = radio_impl.h radio_output.h rtl_fm.h convenience/convenience.h
+SOURCES = radio-binding.c radio_output.c radio_impl_rtlsdr.c rtl_fm.c convenience/convenience.c
+
+LIBS += -Wl,--version-script=$$PWD/export.map
+
+CONFIG += link_pkgconfig
+PKGCONFIG += json-c afb-daemon librtlsdr glib-2.0 libpulse-simple
+
+include(binding.pri)
diff --git a/binding/convenience/convenience.c b/binding/convenience/convenience.c
new file mode 100644
index 0000000..517dc4e
--- /dev/null
+++ b/binding/convenience/convenience.c
@@ -0,0 +1,304 @@
+/*
+ * Copyright (C) 2014 by Kyle Keen <keenerd@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* a collection of user friendly tools
+ * todo: use strtol for more flexible int parsing
+ * */
+
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifndef _WIN32
+#include <unistd.h>
+#else
+#include <windows.h>
+#include <fcntl.h>
+#include <io.h>
+#define _USE_MATH_DEFINES
+#endif
+
+#include <math.h>
+
+#include "rtl-sdr.h"
+
+double atofs(char *s)
+/* standard suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case 'g':
+		case 'G':
+			suff *= 1e3;
+		case 'm':
+		case 'M':
+			suff *= 1e3;
+		case 'k':
+		case 'K':
+			suff *= 1e3;
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+double atoft(char *s)
+/* time suffixes, returns seconds */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case 'h':
+		case 'H':
+			suff *= 60;
+		case 'm':
+		case 'M':
+			suff *= 60;
+		case 's':
+		case 'S':
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+double atofp(char *s)
+/* percent suffixes */
+{
+	char last;
+	int len;
+	double suff = 1.0;
+	len = strlen(s);
+	last = s[len-1];
+	s[len-1] = '\0';
+	switch (last) {
+		case '%':
+			suff *= 0.01;
+			suff *= atof(s);
+			s[len-1] = last;
+			return suff;
+	}
+	s[len-1] = last;
+	return atof(s);
+}
+
+int nearest_gain(rtlsdr_dev_t *dev, int target_gain)
+{
+	int i, r, err1, err2, count, nearest;
+	int* gains;
+	r = rtlsdr_set_tuner_gain_mode(dev, 1);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
+		return r;
+	}
+	count = rtlsdr_get_tuner_gains(dev, NULL);
+	if (count <= 0) {
+		return 0;
+	}
+	gains = malloc(sizeof(int) * count);
+	count = rtlsdr_get_tuner_gains(dev, gains);
+	nearest = gains[0];
+	for (i=0; i<count; i++) {
+		err1 = abs(target_gain - nearest);
+		err2 = abs(target_gain - gains[i]);
+		if (err2 < err1) {
+			nearest = gains[i];
+		}
+	}
+	free(gains);
+	return nearest;
+}
+
+int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency)
+{
+	int r;
+	r = rtlsdr_set_center_freq(dev, frequency);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set center freq.\n");
+	} else {
+		fprintf(stderr, "Tuned to %u Hz.\n", frequency);
+	}
+	return r;
+}
+
+int verbose_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate)
+{
+	int r;
+	r = rtlsdr_set_sample_rate(dev, samp_rate);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set sample rate.\n");
+	} else {
+		fprintf(stderr, "Sampling at %u S/s.\n", samp_rate);
+	}
+	return r;
+}
+
+int verbose_direct_sampling(rtlsdr_dev_t *dev, int on)
+{
+	int r;
+	r = rtlsdr_set_direct_sampling(dev, on);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set direct sampling mode.\n");
+		return r;
+	}
+	if (on == 0) {
+		fprintf(stderr, "Direct sampling mode disabled.\n");}
+	if (on == 1) {
+		fprintf(stderr, "Enabled direct sampling mode, input 1/I.\n");}
+	if (on == 2) {
+		fprintf(stderr, "Enabled direct sampling mode, input 2/Q.\n");}
+	return r;
+}
+
+int verbose_offset_tuning(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_set_offset_tuning(dev, 1);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set offset tuning.\n");
+	} else {
+		fprintf(stderr, "Offset tuning mode enabled.\n");
+	}
+	return r;
+}
+
+int verbose_auto_gain(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_set_tuner_gain_mode(dev, 0);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
+	} else {
+		fprintf(stderr, "Tuner gain set to automatic.\n");
+	}
+	return r;
+}
+
+int verbose_gain_set(rtlsdr_dev_t *dev, int gain)
+{
+	int r;
+	r = rtlsdr_set_tuner_gain_mode(dev, 1);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to enable manual gain.\n");
+		return r;
+	}
+	r = rtlsdr_set_tuner_gain(dev, gain);
+	if (r != 0) {
+		fprintf(stderr, "WARNING: Failed to set tuner gain.\n");
+	} else {
+		fprintf(stderr, "Tuner gain set to %0.2f dB.\n", gain/10.0);
+	}
+	return r;
+}
+
+int verbose_ppm_set(rtlsdr_dev_t *dev, int ppm_error)
+{
+	int r;
+	if (ppm_error == 0) {
+		return 0;}
+	r = rtlsdr_set_freq_correction(dev, ppm_error);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set ppm error.\n");
+	} else {
+		fprintf(stderr, "Tuner error set to %i ppm.\n", ppm_error);
+	}
+	return r;
+}
+
+int verbose_reset_buffer(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_reset_buffer(dev);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to reset buffers.\n");}
+	return r;
+}
+
+int verbose_device_search(char *s)
+{
+	int i, device_count, device, offset;
+	char *s2;
+	char vendor[256], product[256], serial[256];
+	device_count = rtlsdr_get_device_count();
+	if (!device_count) {
+		fprintf(stderr, "No supported devices found.\n");
+		return -1;
+	}
+	fprintf(stderr, "Found %d device(s):\n", device_count);
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		fprintf(stderr, "  %d:  %s, %s, SN: %s\n", i, vendor, product, serial);
+	}
+	fprintf(stderr, "\n");
+	/* does string look like raw id number */
+	device = (int)strtol(s, &s2, 0);
+	if (s2[0] == '\0' && device >= 0 && device < device_count) {
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string exact match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		if (strcmp(s, serial) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string prefix match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		if (strncmp(s, serial, strlen(s)) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	/* does string suffix match a serial */
+	for (i = 0; i < device_count; i++) {
+		rtlsdr_get_device_usb_strings(i, vendor, product, serial);
+		offset = strlen(serial) - strlen(s);
+		if (offset < 0) {
+			continue;}
+		if (strncmp(s, serial+offset, strlen(s)) != 0) {
+			continue;}
+		device = i;
+		fprintf(stderr, "Using device %d: %s\n",
+			device, rtlsdr_get_device_name((uint32_t)device));
+		return device;
+	}
+	fprintf(stderr, "No matching devices found.\n");
+	return -1;
+}
+
+// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab
diff --git a/binding/convenience/convenience.h b/binding/convenience/convenience.h
new file mode 100644
index 0000000..1faa2af
--- /dev/null
+++ b/binding/convenience/convenience.h
@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) 2014 by Kyle Keen <keenerd@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* a collection of user friendly tools */
+
+/*!
+ * Convert standard suffixes (k, M, G) to double
+ *
+ * \param s a string to be parsed
+ * \return double
+ */
+
+double atofs(char *s);
+
+/*!
+ * Convert time suffixes (s, m, h) to double
+ *
+ * \param s a string to be parsed
+ * \return seconds as double
+ */
+
+double atoft(char *s);
+
+/*!
+ * Convert percent suffixe (%) to double
+ *
+ * \param s a string to be parsed
+ * \return double
+ */
+
+double atofp(char *s);
+
+/*!
+ * Find nearest supported gain
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param target_gain in tenths of a dB
+ * \return 0 on success
+ */
+
+int nearest_gain(rtlsdr_dev_t *dev, int target_gain);
+
+/*!
+ * Set device frequency and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param frequency in Hz
+ * \return 0 on success
+ */
+
+int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency);
+
+/*!
+ * Set device sample rate and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param samp_rate in samples/second
+ * \return 0 on success
+ */
+
+int verbose_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate);
+
+/*!
+ * Enable or disable the direct sampling mode and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param on 0 means disabled, 1 I-ADC input enabled, 2 Q-ADC input enabled
+ * \return 0 on success
+ */
+
+int verbose_direct_sampling(rtlsdr_dev_t *dev, int on);
+
+/*!
+ * Enable offset tuning and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_offset_tuning(rtlsdr_dev_t *dev);
+
+/*!
+ * Enable auto gain and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_auto_gain(rtlsdr_dev_t *dev);
+
+/*!
+ * Set tuner gain and report status on stderr
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param gain in tenths of a dB
+ * \return 0 on success
+ */
+
+int verbose_gain_set(rtlsdr_dev_t *dev, int gain);
+
+/*!
+ * Set the frequency correction value for the device and report status on stderr.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \param ppm_error correction value in parts per million (ppm)
+ * \return 0 on success
+ */
+
+int verbose_ppm_set(rtlsdr_dev_t *dev, int ppm_error);
+
+/*!
+ * Reset buffer
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on success
+ */
+
+int verbose_reset_buffer(rtlsdr_dev_t *dev);
+
+/*!
+ * Find the closest matching device.
+ *
+ * \param s a string to be parsed
+ * \return dev_index int, -1 on error
+ */
+
+int verbose_device_search(char *s);
+
diff --git a/binding/export.map b/binding/export.map
new file mode 100644
index 0000000..52c1b4a
--- /dev/null
+++ b/binding/export.map
@@ -0,0 +1 @@
+{ global: afbBindingV1*; local: *; };
diff --git a/binding/radio-binding.c b/binding/radio-binding.c
new file mode 100644
index 0000000..12ed966
--- /dev/null
+++ b/binding/radio-binding.c
@@ -0,0 +1,493 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include <json-c/json.h>
+#include <afb/afb-binding.h>
+#include <afb/afb-service-itf.h>
+
+#include "radio_impl.h"
+
+static const struct afb_binding_interface *interface;
+
+static struct afb_event freq_event;
+static struct afb_event scan_event;
+
+static void freq_callback(uint32_t frequency, void *data)
+{
+	json_object *jresp = json_object_new_object();
+	json_object *value = json_object_new_int((int) frequency);
+
+	json_object_object_add(jresp, "value", value);
+	afb_event_push(freq_event, json_object_get(jresp));
+}
+
+static void scan_callback(uint32_t frequency, void *data)
+{
+	json_object *jresp = json_object_new_object();
+	json_object *value = json_object_new_int((int) frequency);
+
+	json_object_object_add(jresp, "value", value);
+	afb_event_push(scan_event, json_object_get(jresp));
+}
+
+/*
+ * Binding verb handlers
+ */
+
+/*
+ * @brief Get (and optionally set) frequency
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void frequency(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "value");
+	uint32_t frequency;
+
+	if(value) {
+		char *p;
+		frequency = strtoul(value, &p, 10);
+		if(frequency && *p == '\0') {
+			radio_impl_set_frequency(frequency);
+		} else {
+			afb_req_fail(request, "failed", "Invalid scan direction");
+			return;
+		}
+	}
+	ret_json = json_object_new_object();
+	frequency = radio_impl_get_frequency();
+	json_object_object_add(ret_json, "frequency", json_object_new_int((int32_t) frequency));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Get (and optionally set) frequency band
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void band(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "value");
+	int valid = 0;
+	radio_band_t band;
+	char band_name[4];
+
+	if(value) {
+		if(!strcasecmp(value, "AM")) {
+			band = BAND_AM;
+			valid = 1;
+		} else if(!strcasecmp(value, "FM")) {
+			band = BAND_FM;
+			valid = 1;
+		} else {
+			char *p;
+			band = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(band) {
+				case BAND_AM:
+				case BAND_FM:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+		if(valid) {
+			radio_impl_set_band(band);
+		} else {
+			afb_req_fail(request, "failed", "Invalid band");
+			return;
+		}
+	}
+	ret_json = json_object_new_object();
+	band = radio_impl_get_band();
+	sprintf(band_name, "%s", band == BAND_AM ? "AM" : "FM");
+	json_object_object_add(ret_json, "band", json_object_new_string(band_name));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Check if band is supported
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void band_supported(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "band");
+	int valid = 0;
+	radio_band_t band;
+
+	if(value) {
+		if(!strcasecmp(value, "AM")) {
+			band = BAND_AM;
+			valid = 1;
+		} else if(!strcasecmp(value, "FM")) {
+			band = BAND_FM;
+			valid = 1;
+		} else {
+			char *p;
+			band = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(band) {
+				case BAND_AM:
+				case BAND_FM:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+	}
+	if(!valid) {
+		afb_req_fail(request, "failed", "Invalid band");
+		return;
+	}
+	ret_json = json_object_new_object();
+	json_object_object_add(ret_json,
+			       "supported",
+			       json_object_new_int(radio_impl_band_supported(band)));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Get frequency range for a band
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void frequency_range(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "band");
+	int valid = 0;
+	radio_band_t band;
+	uint32_t min_frequency;
+	uint32_t max_frequency;
+
+	if(value) {
+		if(!strcasecmp(value, "AM")) {
+			band = BAND_AM;
+			valid = 1;
+		} else if(!strcasecmp(value, "FM")) {
+			band = BAND_FM;
+			valid = 1;
+		} else {
+			char *p;
+			band = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(band) {
+				case BAND_AM:
+				case BAND_FM:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+	}
+	if(!valid) {
+		afb_req_fail(request, "failed", "Invalid band");
+		return;
+	}
+	ret_json = json_object_new_object();
+	min_frequency = radio_impl_get_min_frequency(band);
+	max_frequency = radio_impl_get_max_frequency(band);
+	json_object_object_add(ret_json, "min", json_object_new_int((int32_t) min_frequency));
+	json_object_object_add(ret_json, "max", json_object_new_int((int32_t) max_frequency));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Get frequency step size (Hz) for a band
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void frequency_step(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "band");
+	int valid = 0;
+	radio_band_t band;
+	uint32_t step;
+
+	if(value) {
+		if(!strcasecmp(value, "AM")) {
+			band = BAND_AM;
+			valid = 1;
+		} else if(!strcasecmp(value, "FM")) {
+			band = BAND_FM;
+			valid = 1;
+		} else {
+			char *p;
+			band = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(band) {
+				case BAND_AM:
+				case BAND_FM:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+	}
+	if(!valid) {
+		afb_req_fail(request, "failed", "Invalid band");
+		return;
+	}
+	ret_json = json_object_new_object();
+	step = radio_impl_get_frequency_step(band);
+	json_object_object_add(ret_json, "step", json_object_new_int((int32_t) step));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Start radio playback
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void start(struct afb_req request)
+{
+	radio_impl_start();
+	afb_req_success(request, NULL, NULL);
+}
+
+/*
+ * @brief Stop radio playback
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void stop(struct afb_req request)
+{
+	radio_impl_stop();
+	afb_req_success(request, NULL, NULL);
+}
+
+/*
+ * @brief Scan for a station in the specified direction
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void scan_start(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "direction");
+	int valid = 0;
+	radio_scan_direction_t direction;
+
+	if(value) {
+		if(!strcasecmp(value, "forward")) {
+			direction = SCAN_FORWARD;
+			valid = 1;
+		} else if(!strcasecmp(value, "backward")) {
+			direction = SCAN_BACKWARD;
+			valid = 1;
+		} else {
+			char *p;
+			direction = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(direction) {
+				case SCAN_FORWARD:
+				case SCAN_BACKWARD:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+	}
+	if(!valid) {
+		afb_req_fail(request, "failed", "Invalid direction");
+		return;
+	}
+	radio_impl_scan_start(direction, scan_callback, NULL);
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Stop station scan
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void scan_stop(struct afb_req request)
+{
+	radio_impl_scan_stop();
+	afb_req_success(request, NULL, NULL);
+}
+
+/*
+ * @brief Get (and optionally set) stereo mode
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void stereo_mode(struct afb_req request)
+{
+	json_object *ret_json;
+	const char *value = afb_req_value(request, "value");
+	int valid = 0;
+	radio_stereo_mode_t mode;
+	char mode_name[4];
+
+	if(value) {
+		if(!strcasecmp(value, "mono")) {
+			mode = MONO;
+			valid = 1;
+		} else if(!strcasecmp(value, "stereo")) {
+			mode = STEREO;
+			valid = 1;
+		} else {
+			char *p;
+			mode = strtoul(value, &p, 10);
+			if(p != value && *p == '\0') {
+				switch(mode) {
+				case MONO:
+				case STEREO:
+					valid = 1;
+					break;
+				default:
+					break;
+				}
+			}
+		}
+		if(valid) {
+			radio_impl_set_stereo_mode(mode);
+		} else {
+			afb_req_fail(request, "failed", "Invalid mode");
+			return;
+		}
+	}
+	ret_json = json_object_new_object();
+	mode = radio_impl_get_stereo_mode();
+	sprintf(mode_name, "%s", mode == MONO ? "mono" : "stereo");
+	json_object_object_add(ret_json, "mode", json_object_new_string(mode_name));
+	afb_req_success(request, ret_json, NULL);
+}
+
+/*
+ * @brief Subscribe for an event
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void subscribe(struct afb_req request)
+{
+	const char *value = afb_req_value(request, "value");
+	if(value) {
+		if(!strcasecmp(value, "frequency")) {
+			afb_req_subscribe(request, freq_event);
+		} else if(!strcasecmp(value, "station_found")) {
+			afb_req_subscribe(request, scan_event);
+		} else {
+			afb_req_fail(request, "failed", "Invalid event");
+			return;
+		}
+	}
+	afb_req_success(request, NULL, NULL);
+}
+
+/*
+ * @brief Unsubscribe for an event
+ *
+ * @param struct afb_req : an afb request structure
+ *
+ */
+static void unsubscribe(struct afb_req request)
+{
+	const char *value = afb_req_value(request, "value");
+	if(value) {
+		if(!strcasecmp(value, "frequency")) {
+			afb_req_unsubscribe(request, freq_event);
+		} else if(!strcasecmp(value, "station_found")) {
+			afb_req_unsubscribe(request, scan_event);
+		} else {
+			afb_req_fail(request, "failed", "Invalid event");
+			return;
+		}
+	}
+	afb_req_success(request, NULL, NULL);
+}
+
+static const struct afb_verb_desc_v1 verbs[]= {
+	{ "frequency",		AFB_SESSION_CHECK, frequency,		"Get/Set frequency" },
+	{ "band",		AFB_SESSION_CHECK, band,		"Get/Set band" },
+	{ "band_supported",	AFB_SESSION_CHECK, band_supported,	"Check band support" },
+	{ "frequency_range",	AFB_SESSION_CHECK, frequency_range,	"Get frequency range" },
+	{ "frequency_step",	AFB_SESSION_CHECK, frequency_step,	"Get frequency step" },
+	{ "start",		AFB_SESSION_CHECK, start,		"Start radio playback" },
+	{ "stop",		AFB_SESSION_CHECK, stop,		"Stop radio playback" },
+	{ "scan_start",		AFB_SESSION_CHECK, scan_start,		"Start station scan" },
+	{ "scan_stop",		AFB_SESSION_CHECK, scan_stop,		"Stop station scan" },
+	{ "stereo_mode",	AFB_SESSION_CHECK, stereo_mode,		"Get/Set stereo_mode" },
+	{ "subscribe",		AFB_SESSION_CHECK, subscribe,		"Subscribe for an event" },
+	{ "unsubscribe",	AFB_SESSION_CHECK, unsubscribe,		"Unsubscribe for an event" },
+	{ NULL }
+};
+
+static const struct afb_binding binding_desc = {
+	.type = AFB_BINDING_VERSION_1,
+	.v1 = {
+		.info = "radio service",
+		.prefix = "radio",
+		.verbs = verbs
+	}
+};
+
+const struct afb_binding *afbBindingV1Register (const struct afb_binding_interface *itf)
+{
+	interface = itf;
+
+	return &binding_desc;
+}
+
+int afbBindingV1ServiceInit(struct afb_service service)
+{
+	int rc;
+
+	freq_event = afb_daemon_make_event(interface->daemon, "frequency");
+	scan_event = afb_daemon_make_event(interface->daemon, "station_found");
+
+	rc = radio_impl_init();
+	if(rc == 0) {
+		radio_impl_set_frequency_callback(freq_callback, NULL);
+	}
+	
+	return rc;
+}
diff --git a/binding/radio_impl.h b/binding/radio_impl.h
new file mode 100644
index 0000000..79e91a4
--- /dev/null
+++ b/binding/radio_impl.h
@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _RADIO_IMPL_H
+#define _RADIO_IMPL_H
+
+#include <stdint.h>
+
+typedef enum {
+	BAND_AM = 0,
+	BAND_FM
+} radio_band_t;
+
+typedef enum {
+	SCAN_FORWARD = 0,
+	SCAN_BACKWARD
+} radio_scan_direction_t;
+
+typedef void (*radio_scan_callback_t)(uint32_t frequency, void *data);
+
+typedef void (*radio_freq_callback_t)(uint32_t frequency, void *data);
+
+typedef enum {
+	MONO = 0,
+	STEREO
+} radio_stereo_mode_t;
+
+int radio_impl_init(void);
+
+uint32_t radio_impl_get_frequency(void);
+
+void radio_impl_set_frequency(uint32_t frequency);
+
+void radio_impl_set_frequency_callback(radio_freq_callback_t callback,
+				       void *data);
+
+radio_band_t radio_impl_get_band(void);
+
+void radio_impl_set_band(radio_band_t band);
+
+int radio_impl_band_supported(radio_band_t band);
+
+uint32_t radio_impl_get_min_frequency(radio_band_t band);
+
+uint32_t radio_impl_get_max_frequency(radio_band_t band);
+
+uint32_t radio_impl_get_frequency_step(radio_band_t band);
+
+void radio_impl_start(void);
+
+void radio_impl_stop(void);
+
+void radio_impl_scan_start(radio_scan_direction_t direction,
+			   radio_scan_callback_t callback,
+			   void *data);
+
+void radio_impl_scan_stop(void);
+
+radio_stereo_mode_t radio_impl_get_stereo_mode(void);
+
+void radio_impl_set_stereo_mode(radio_stereo_mode_t mode);
+
+#endif /* _RADIO_IMPL_H */
diff --git a/binding/radio_impl_rtlsdr.c b/binding/radio_impl_rtlsdr.c
new file mode 100644
index 0000000..4364fd5
--- /dev/null
+++ b/binding/radio_impl_rtlsdr.c
@@ -0,0 +1,254 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <glib.h>
+
+#include "radio_impl.h"
+#include "radio_output.h"
+#include "rtl_fm.h"
+
+// Structure to describe FM band plans, all values in Hz.
+typedef struct {
+	char *name;
+	uint32_t min;
+	uint32_t max;
+	uint32_t step;
+} fm_band_plan_t;
+
+static fm_band_plan_t known_fm_band_plans[5] = {
+	{ .name = "US", .min = 87900000, .max = 107900000, .step = 200000 },
+	{ .name = "JP", .min = 76100000, .max = 89900000, .step = 100000 },
+	{ .name = "EU", .min = 87500000, .max = 108000000, .step = 50000 },
+	{ .name = "ITU-1", .min = 87500000, .max = 108000000, .step = 50000 },
+	{ .name = "ITU-2", .min = 87900000, .max = 107900000, .step = 50000 }
+};
+
+static unsigned int bandplan;
+static bool present;
+static bool active;
+static uint32_t current_frequency;
+
+static void rtl_output_callback(int16_t *result, int result_len, void *ctx)
+{
+    if(active)
+	    radio_output_write((char*) result, result_len * 2);
+}
+
+int radio_impl_init(void)
+{
+	GKeyFile* conf_file;
+	int conf_file_present = 0;
+	char *value_str;
+
+	if(present)
+		return -1;
+
+	// Load settings from configuration file if it exists
+	conf_file = g_key_file_new();
+	if(conf_file &&
+	   g_key_file_load_from_dirs(conf_file,
+				     "AGL.conf",
+				     (const gchar**) g_get_system_config_dirs(),
+				     NULL,
+				     G_KEY_FILE_KEEP_COMMENTS,
+				     NULL) == TRUE) {
+		conf_file_present = 1;
+
+		// Set band plan if it is specified
+		value_str = g_key_file_get_string(conf_file,
+						  "radio",
+						  "fmbandplan",
+						  NULL);
+		if(value_str) {
+			unsigned int i;
+			for(i = 0;
+			    i < sizeof(known_fm_band_plans) / sizeof(fm_band_plan_t);
+			    i++) {
+				if(!strcasecmp(value_str, known_fm_band_plans[i].name)) {
+					bandplan = i;
+					break;
+				}
+			}
+		}
+	}
+	fprintf(stderr, "Using FM Bandplan: %s\n", known_fm_band_plans[bandplan].name);
+
+	current_frequency = radio_impl_get_min_frequency(BAND_FM);
+	if(rtl_fm_init(current_frequency, 200000, 48000, rtl_output_callback, NULL) < 0) {
+		return -1;
+	}
+
+	if(conf_file_present) {
+		GError *error = NULL;
+		int n;
+
+		// Allow over-riding scanning parameters just in case a demo
+		// setup needs to do so to work reliably.
+		n = g_key_file_get_integer(conf_file,
+					   "radio",
+					   "scan_squelch_level",
+					   &error);
+		//error->code != G_KEY_FILE_ERROR_KEY_NOT_FOUND &&
+		//error->code != G_KEY_FILE_ERROR_INVALID_VALUE) {
+		if(!error) {
+			fprintf(stderr, "Scanning squelch level set to %d\n", n);
+			rtl_fm_scan_set_squelch_level(n);
+		}
+
+		error = NULL;
+		n = g_key_file_get_integer(conf_file,
+					   "radio",
+					   "scan_squelch_limit",
+					   &error);
+		if(!error) {
+			fprintf(stderr, "Scanning squelch limit set to %d\n", n);
+			rtl_fm_scan_set_squelch_limit(n);
+		}
+
+		g_key_file_free(conf_file);
+	}
+
+	present = true;
+	return 0;
+}
+
+uint32_t radio_impl_get_frequency(void)
+{
+	return current_frequency;
+}
+
+void radio_impl_set_frequency(uint32_t frequency)
+{
+	if(!present)
+		return;
+
+	if(frequency < known_fm_band_plans[bandplan].min ||
+	   frequency > known_fm_band_plans[bandplan].max)
+		return;
+
+	radio_impl_scan_stop();
+	current_frequency = frequency;
+	rtl_fm_set_freq(frequency);
+}
+
+void radio_impl_set_frequency_callback(radio_freq_callback_t callback,
+				       void *data)
+{
+	rtl_fm_set_freq_callback(callback, data);
+}
+
+radio_band_t radio_impl_get_band(void)
+{
+	return BAND_FM;
+}
+
+void radio_impl_set_band(radio_band_t band)
+{
+	// We only support FM, so do nothing
+}
+
+int radio_impl_band_supported(radio_band_t band)
+{
+	if(band == BAND_FM)
+		return 1;
+	return 0;
+}
+
+uint32_t radio_impl_get_min_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].min;
+}
+
+uint32_t radio_impl_get_max_frequency(radio_band_t band)
+{
+	return known_fm_band_plans[bandplan].max;
+}
+
+uint32_t radio_impl_get_frequency_step(radio_band_t band)
+{
+	uint32_t ret = 0;
+
+	switch (band) {
+	case BAND_AM:
+		ret = 1000; // 1 kHz
+		break;
+	case BAND_FM:
+		ret = known_fm_band_plans[bandplan].step;
+		break;
+	default:
+		break;
+	}
+	return ret;
+}
+
+void radio_impl_start(void)
+{
+	if(!present)
+		return;
+
+	if(!active) {
+		if(radio_output_start() != 0)
+			return;
+
+		rtl_fm_start();
+		active = true;
+	}
+}
+
+void radio_impl_stop(void)
+{
+	if(!present)
+		return;
+
+	if(active) {
+		active = false;
+		radio_output_stop();
+		rtl_fm_stop();
+
+	}
+}
+
+void radio_impl_scan_start(radio_scan_direction_t direction,
+			   radio_scan_callback_t callback,
+			   void *data)
+{
+	rtl_fm_scan_start(direction == SCAN_FORWARD ? 0 : 1,
+			  callback,
+			  data,
+			  radio_impl_get_frequency_step(BAND_FM),
+			  radio_impl_get_min_frequency(BAND_FM),
+			  radio_impl_get_max_frequency(BAND_FM));
+}
+
+void radio_impl_scan_stop(void)
+{
+	rtl_fm_scan_stop();
+}
+
+radio_stereo_mode_t radio_impl_get_stereo_mode(void)
+{
+	return STEREO;
+}
+
+void radio_impl_set_stereo_mode(radio_stereo_mode_t mode)
+{
+	// We only support stereo, so do nothing
+}
diff --git a/binding/radio_output.c b/binding/radio_output.c
new file mode 100644
index 0000000..a49687b
--- /dev/null
+++ b/binding/radio_output.c
@@ -0,0 +1,294 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <pulse/pulseaudio.h>
+
+#include "radio_output.h"
+#include "rtl_fm.h"
+
+static pa_threaded_mainloop *mainloop;
+static pa_context *context;
+static pa_stream *stream;
+
+static unsigned int extra;
+static int16_t extra_buf[1];
+static unsigned char *output_buf;
+
+static void pa_context_state_cb(pa_context *c, void *data) {
+	pa_operation *o;
+
+	assert(c);
+	switch (pa_context_get_state(c)) {
+		case PA_CONTEXT_CONNECTING:
+		case PA_CONTEXT_AUTHORIZING:
+		case PA_CONTEXT_SETTING_NAME:
+		case PA_CONTEXT_READY:
+			break;
+		case PA_CONTEXT_TERMINATED:
+			pa_threaded_mainloop_stop(mainloop);
+			break;
+		case PA_CONTEXT_FAILED:
+		default:
+			fprintf(stderr, "PA connection failed: %s\n",
+				pa_strerror(pa_context_errno(c)));
+			pa_threaded_mainloop_stop(mainloop);
+			break;
+	}
+	pa_threaded_mainloop_signal(mainloop, 0);
+}
+
+int radio_output_open(void)
+{
+	pa_context *c;
+	pa_mainloop_api *mapi;
+	char *client;
+
+	if(context)
+		return 0;
+
+	if (!(mainloop = pa_threaded_mainloop_new())) {
+		fprintf(stderr, "pa_mainloop_new() failed.\n");
+		return -1;
+	}
+
+	pa_threaded_mainloop_set_name(mainloop, "pa_mainloop");
+	mapi = pa_threaded_mainloop_get_api(mainloop);
+
+	client = pa_xstrdup("radio");
+	if (!(c = pa_context_new(mapi, client))) {
+		fprintf(stderr, "pa_context_new() failed.\n");
+		goto exit;
+	}
+
+	pa_context_set_state_callback(c, pa_context_state_cb, NULL);
+	if (pa_context_connect(c, NULL, 0, NULL) < 0) {
+		fprintf(stderr, "pa_context_connect(): %s", pa_strerror(pa_context_errno(c)));
+		goto exit;
+	}
+
+	if (pa_threaded_mainloop_start(mainloop) < 0) {
+		fprintf(stderr, "pa_mainloop_run() failed.\n");
+		goto exit;
+	}
+
+	context = c;
+
+	extra = 0;
+	output_buf = malloc(sizeof(unsigned char) * RTL_FM_MAXIMUM_BUF_LENGTH);
+
+	return 0;
+
+exit:
+	if (c)
+		pa_context_unref(c);
+
+	if (mainloop)
+		pa_threaded_mainloop_free(mainloop);
+
+	pa_xfree(client);
+	return -1;
+}
+
+int radio_output_start(void)
+{
+	int error = 0;
+	pa_sample_spec *spec;
+
+	if(stream)
+		return 0;
+
+	if(!context) {
+		error = radio_output_open();
+		if(error != 0)
+			return error;
+	}
+
+	while(pa_context_get_state(context) != PA_CONTEXT_READY)
+		pa_threaded_mainloop_wait(mainloop);
+
+	spec = (pa_sample_spec*) calloc(1, sizeof(pa_sample_spec));
+	spec->format = PA_SAMPLE_S16LE;
+	spec->rate = 24000;
+	spec->channels = 2;
+	if (!pa_sample_spec_valid(spec)) {
+		fprintf(stderr, "%s\n",
+			pa_strerror(pa_context_errno(context)));
+		return -1;
+	}
+
+	pa_threaded_mainloop_lock(mainloop);
+	pa_proplist *props = pa_proplist_new();
+	pa_proplist_sets(props, PA_PROP_MEDIA_ROLE, "radio");
+	stream = pa_stream_new_with_proplist(context, "radio-output", spec, 0, props);
+	if(!stream) {
+		fprintf(stderr, "Error creating stream %s\n",
+			pa_strerror(pa_context_errno(context)));
+		pa_proplist_free(props);
+		free(spec);
+		pa_threaded_mainloop_unlock(mainloop);
+		return -1;
+	}
+	pa_proplist_free(props);
+	free(spec);
+
+	if(pa_stream_connect_playback(stream,
+				      NULL,
+				      NULL,
+				      (pa_stream_flags_t) 0,
+				      NULL,
+				      NULL) < 0) {
+		fprintf(stderr, "Error connecting to PulseAudio : %s\n",
+			pa_strerror(pa_context_errno(context)));
+		pa_stream_unref(stream);
+		stream = NULL;
+		pa_threaded_mainloop_unlock(mainloop);
+		return -1;
+	}
+
+	pa_threaded_mainloop_unlock(mainloop);
+
+	while(pa_stream_get_state(stream) != PA_STREAM_READY)
+		pa_threaded_mainloop_wait(mainloop);
+
+	return error;
+}
+
+void radio_output_stop(void)
+{
+	if(stream) {
+		pa_threaded_mainloop_lock(mainloop);
+
+		pa_stream_set_state_callback(stream, 0, 0);
+		pa_stream_set_write_callback(stream, 0, 0);
+		pa_stream_set_underflow_callback(stream, 0, 0);
+		pa_stream_set_overflow_callback(stream, 0, 0);
+		pa_stream_set_latency_update_callback(stream, 0, 0);
+
+		pa_operation *o = pa_stream_flush(stream, NULL, NULL);
+		if(o)
+			pa_operation_unref(o);
+
+		pa_stream_disconnect(stream);
+		pa_stream_unref(stream);
+		stream = NULL;
+
+		pa_threaded_mainloop_unlock(mainloop);
+	}
+}
+
+void radio_output_suspend(int state)
+{
+	if(stream) {
+		pa_stream_cork(stream, state, NULL, NULL);
+	}
+}
+
+void radio_output_close(void)
+{
+	radio_output_stop();
+
+	if(context) {
+		pa_context_disconnect(context);
+		pa_context_unref(context);
+		context = NULL;
+	}
+
+	if(mainloop) {
+		pa_threaded_mainloop_stop(mainloop);
+		pa_threaded_mainloop_free(mainloop);
+		mainloop = NULL;
+	}
+
+	free(output_buf);
+	output_buf = NULL;
+}
+
+int radio_output_write(void *buf, int len)
+{
+	int rc = -EINVAL;
+	int error;
+	size_t n = len;
+	size_t avail;
+	int samples = len / 2;
+	void *p;
+
+	if(!stream) {
+		return -1;
+	}
+
+	if(!buf) {
+		fprintf(stderr, "Error: buf == null!\n");
+		return rc;
+	}
+
+	pa_threaded_mainloop_lock(mainloop);
+
+	avail = pa_stream_writable_size(stream);
+	if(avail < n) {
+		/*
+		 * NOTE: Definitely room for improvement here,but for now just
+		 *       check for the no space case that happens when the
+		 *       stream is corked.
+		 */
+		if(!avail) {
+			rc = 0;
+			goto exit;
+		}
+	}
+
+	/*
+	 * Handle the rtl_fm code giving us an odd number of samples, which
+	 * PA does not like.  This extra buffer copying approach is not
+	 * particularly efficient, but works for now.  It looks feasible to
+	 * hack in something in the demod and output thread routines in
+	 * rtl_fm.c to handle it there if more performance is required.
+	 */
+	p = output_buf;
+	if(extra) {
+		memcpy(output_buf, extra_buf, sizeof(int16_t));
+		if((extra + samples) % 2) {
+			// We still have an extra sample, n remains the same, store the extra
+			memcpy(output_buf + sizeof(int16_t), buf, n - 2);
+			memcpy(extra_buf, ((unsigned char*) buf) + n - 2, sizeof(int16_t));
+		} else {
+			// We have an even number of samples, no extra
+			memcpy(output_buf + sizeof(int16_t), buf, n);
+			n += 2;
+			extra = 0;
+		}
+	} else if(samples % 2) {
+		// We have an extra sample, store it, and decrease n
+		n -= 2;
+		memcpy(output_buf + sizeof(int16_t), buf, n);
+		memcpy(extra_buf, ((unsigned char*) buf) + n, sizeof(int16_t));
+		extra = 1;
+	} else {
+		p = buf;
+	}
+
+	if ((rc = pa_stream_write(stream, p, n, NULL, 0, PA_SEEK_RELATIVE)) < 0) {
+		fprintf(stderr, "Error writing %d bytes to PulseAudio : %s\n",
+			n, pa_strerror(pa_context_errno(context)));
+	}
+exit:
+	pa_threaded_mainloop_unlock(mainloop);
+
+	return rc;
+}
diff --git a/binding/radio_output.h b/binding/radio_output.h
new file mode 100644
index 0000000..2192811
--- /dev/null
+++ b/binding/radio_output.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _RADIO_OUTPUT_H
+#define _RADIO_OUTPUT_H
+
+int radio_output_open(void);
+
+int radio_output_start(void);
+
+void radio_output_stop(void);
+
+void radio_output_close(void);
+
+int radio_output_write(void *buf, int len);
+
+#endif /* _RADIO_OUTPUT_H */
+
diff --git a/binding/rtl_fm.c b/binding/rtl_fm.c
new file mode 100644
index 0000000..1c6a6b2
--- /dev/null
+++ b/binding/rtl_fm.c
@@ -0,0 +1,1267 @@
+/*
+ * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
+ * Copyright (C) 2012 by Steve Markgraf <steve@steve-m.de>
+ * Copyright (C) 2012 by Hoernchen <la@tfc-server.de>
+ * Copyright (C) 2012 by Kyle Keen <keenerd@gmail.com>
+ * Copyright (C) 2013 by Elias Oenal <EliasOenal@gmail.com>
+ * Copyright (C) 2016, 2017 Konsulko Group
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * Note that this version replaces the standalone main() with separate
+ * init/start/stop API calls to allow building into another application.
+ * Other than removing the separate controller thread and adding an output
+ * function callback, other changes have been kept to a minimum to
+ * potentially allow using other rtl_fm features by modifying rtl_fm_init.
+ *
+ * December 2016, Scott Murray <scott.murray@konsulko.com>
+ */
+
+/*
+ * written because people could not do real time
+ * FM demod on Atom hardware with GNU radio
+ * based on rtl_sdr.c and rtl_tcp.c
+ *
+ * lots of locks, but that is okay
+ * (no many-to-many locks)
+ *
+ * todo:
+ *       sanity checks
+ *       scale squelch to other input parameters
+ *       test all the demodulations
+ *       pad output on hop
+ *       frequency ranges could be stored better
+ *       scaled AM demod amplification
+ *       auto-hop after time limit
+ *       peak detector to tune onto stronger signals
+ *       fifo for active hop frequency
+ *       clips
+ *       noise squelch
+ *       merge stereo patch
+ *       merge soft agc patch
+ *       merge udp patch
+ *       testmode to detect overruns
+ *       watchdog to reset bad dongle
+ *       fix oversampling
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+#include <pthread.h>
+
+#include "rtl-sdr.h"
+#include "rtl_fm.h"
+#include "convenience/convenience.h"
+
+#define DEFAULT_SAMPLE_RATE		24000
+#define DEFAULT_BUF_LENGTH		RTL_FM_DEFAULT_BUF_LENGTH
+#define MAXIMUM_OVERSAMPLE		RTL_FM_MAXIMUM_OVERSAMPLE
+#define MAXIMUM_BUF_LENGTH		RTL_FM_MAXIMUM_BUF_LENGTH
+#define AUTO_GAIN			-100
+#define BUFFER_DUMP			4096
+
+#define FREQUENCIES_LIMIT		1000
+
+#define DEFAULT_SQUELCH_LEVEL		140
+#define DEFAULT_CONSEQ_SQUELCH		10
+
+static volatile int do_exit = 0;
+static int lcm_post[17] = {1,1,1,3,1,5,3,7,1,9,5,11,3,13,7,15,1};
+static int ACTUAL_BUF_LENGTH;
+
+static int *atan_lut = NULL;
+static int atan_lut_size = 131072; /* 512 KB */
+static int atan_lut_coef = 8;
+
+struct dongle_state
+{
+	int      exit_flag;
+	pthread_t thread;
+	rtlsdr_dev_t *dev;
+	int      dev_index;
+	uint32_t freq;
+	uint32_t rate;
+	int      gain;
+	uint16_t buf16[MAXIMUM_BUF_LENGTH];
+	uint32_t buf_len;
+	int      ppm_error;
+	int      offset_tuning;
+	int      direct_sampling;
+	int      mute;
+	struct demod_state *demod_target;
+};
+
+struct demod_state
+{
+	int      exit_flag;
+	pthread_t thread;
+	int16_t  lowpassed[MAXIMUM_BUF_LENGTH];
+	int      lp_len;
+	int16_t  lp_i_hist[10][6];
+	int16_t  lp_q_hist[10][6];
+	int16_t  result[MAXIMUM_BUF_LENGTH];
+	int16_t  droop_i_hist[9];
+	int16_t  droop_q_hist[9];
+	int      result_len;
+	int      rate_in;
+	int      rate_out;
+	int      rate_out2;
+	int      now_r, now_j;
+	int      pre_r, pre_j;
+	int      prev_index;
+	int      downsample;    /* min 1, max 256 */
+	int      post_downsample;
+	int      output_scale;
+	int      squelch_level, conseq_squelch, squelch_hits, terminate_on_squelch;
+	int      downsample_passes;
+	int      comp_fir_size;
+	int      custom_atan;
+	int      deemph, deemph_a;
+	int      now_lpr;
+	int      prev_lpr_index;
+	int      dc_block, dc_avg;
+	void     (*mode_demod)(struct demod_state*);
+	pthread_rwlock_t rw;
+	pthread_cond_t ready;
+	pthread_mutex_t ready_m;
+	struct output_state *output_target;
+};
+
+struct output_state
+{
+	int      exit_flag;
+	pthread_t thread;
+	rtl_fm_output_fn_t output_fn;
+	void     *output_fn_data;
+	int16_t  result[MAXIMUM_BUF_LENGTH];
+	int      result_len;
+	int      rate;
+	pthread_rwlock_t rw;
+	pthread_cond_t ready;
+	pthread_mutex_t ready_m;
+};
+
+struct controller_state
+{
+	int      exit_flag;
+	pthread_t thread;
+	uint32_t freqs[FREQUENCIES_LIMIT];
+	int      freq_len;
+	int      freq_now;
+	int      edge;
+	int      wb_mode;
+	pthread_cond_t hop;
+	pthread_mutex_t hop_m;
+
+	void (*freq_callback)(uint32_t, void*);
+	void *freq_callback_data;
+
+	int scanning;
+	int scan_direction;
+	void (*scan_callback)(uint32_t, void*);
+	void *scan_callback_data;
+	uint32_t scan_step;
+	uint32_t scan_min;
+	uint32_t scan_max;
+	int scan_squelch_level;
+	int scan_squelch_count;
+};
+
+// multiple of these, eventually
+struct dongle_state dongle;
+struct demod_state demod;
+struct output_state output;
+struct controller_state controller;
+
+#if 0
+static void sighandler(int signum)
+{
+	fprintf(stderr, "Signal caught, exiting!\n");
+	do_exit = 1;
+	rtlsdr_cancel_async(dongle.dev);
+}
+#endif
+
+/* more cond dumbness */
+#define safe_cond_signal(n, m) pthread_mutex_lock(m); pthread_cond_signal(n); pthread_mutex_unlock(m)
+#define safe_cond_wait(n, m) pthread_mutex_lock(m); pthread_cond_wait(n, m); pthread_mutex_unlock(m)
+
+/* {length, coef, coef, coef}  and scaled by 2^15
+   for now, only length 9, optimal way to get +85% bandwidth */
+#define CIC_TABLE_MAX 10
+int cic_9_tables[][10] = {
+	{0,},
+	{9, -156,  -97, 2798, -15489, 61019, -15489, 2798,  -97, -156},
+	{9, -128, -568, 5593, -24125, 74126, -24125, 5593, -568, -128},
+	{9, -129, -639, 6187, -26281, 77511, -26281, 6187, -639, -129},
+	{9, -122, -612, 6082, -26353, 77818, -26353, 6082, -612, -122},
+	{9, -120, -602, 6015, -26269, 77757, -26269, 6015, -602, -120},
+	{9, -120, -582, 5951, -26128, 77542, -26128, 5951, -582, -120},
+	{9, -119, -580, 5931, -26094, 77505, -26094, 5931, -580, -119},
+	{9, -119, -578, 5921, -26077, 77484, -26077, 5921, -578, -119},
+	{9, -119, -577, 5917, -26067, 77473, -26067, 5917, -577, -119},
+	{9, -199, -362, 5303, -25505, 77489, -25505, 5303, -362, -199},
+};
+
+void rotate_90(unsigned char *buf, uint32_t len)
+/* 90 rotation is 1+0j, 0+1j, -1+0j, 0-1j
+   or [0, 1, -3, 2, -4, -5, 7, -6] */
+{
+	uint32_t i;
+	unsigned char tmp;
+	for (i=0; i<len; i+=8) {
+		/* uint8_t negation = 255 - x */
+		tmp = 255 - buf[i+3];
+		buf[i+3] = buf[i+2];
+		buf[i+2] = tmp;
+
+		buf[i+4] = 255 - buf[i+4];
+		buf[i+5] = 255 - buf[i+5];
+
+		tmp = 255 - buf[i+6];
+		buf[i+6] = buf[i+7];
+		buf[i+7] = tmp;
+	}
+}
+
+void low_pass(struct demod_state *d)
+/* simple square window FIR */
+{
+	int i=0, i2=0;
+	while (i < d->lp_len) {
+		d->now_r += d->lowpassed[i];
+		d->now_j += d->lowpassed[i+1];
+		i += 2;
+		d->prev_index++;
+		if (d->prev_index < d->downsample) {
+			continue;
+		}
+		d->lowpassed[i2]   = d->now_r; // * d->output_scale;
+		d->lowpassed[i2+1] = d->now_j; // * d->output_scale;
+		d->prev_index = 0;
+		d->now_r = 0;
+		d->now_j = 0;
+		i2 += 2;
+	}
+	d->lp_len = i2;
+}
+
+int low_pass_simple(int16_t *signal2, int len, int step)
+// no wrap around, length must be multiple of step
+{
+	int i, i2, sum;
+	for(i=0; i < len; i+=step) {
+		sum = 0;
+		for(i2=0; i2<step; i2++) {
+			sum += (int)signal2[i + i2];
+		}
+		//signal2[i/step] = (int16_t)(sum / step);
+		signal2[i/step] = (int16_t)(sum);
+	}
+	signal2[i/step + 1] = signal2[i/step];
+	return len / step;
+}
+
+void low_pass_real(struct demod_state *s)
+/* simple square window FIR */
+// add support for upsampling?
+{
+	int i=0, i2=0;
+	int fast = (int)s->rate_out;
+	int slow = s->rate_out2;
+	while (i < s->result_len) {
+		s->now_lpr += s->result[i];
+		i++;
+		s->prev_lpr_index += slow;
+		if (s->prev_lpr_index < fast) {
+			continue;
+		}
+		s->result[i2] = (int16_t)(s->now_lpr / (fast/slow));
+		s->prev_lpr_index -= fast;
+		s->now_lpr = 0;
+		i2 += 1;
+	}
+	s->result_len = i2;
+}
+
+void fifth_order(int16_t *data, int length, int16_t *hist)
+/* for half of interleaved data */
+{
+	int i;
+	int16_t a, b, c, d, e, f;
+	a = hist[1];
+	b = hist[2];
+	c = hist[3];
+	d = hist[4];
+	e = hist[5];
+	f = data[0];
+	/* a downsample should improve resolution, so don't fully shift */
+	data[0] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
+	for (i=4; i<length; i+=4) {
+		a = c;
+		b = d;
+		c = e;
+		d = f;
+		e = data[i-2];
+		f = data[i];
+		data[i/2] = (a + (b+e)*5 + (c+d)*10 + f) >> 4;
+	}
+	/* archive */
+	hist[0] = a;
+	hist[1] = b;
+	hist[2] = c;
+	hist[3] = d;
+	hist[4] = e;
+	hist[5] = f;
+}
+
+void generic_fir(int16_t *data, int length, int *fir, int16_t *hist)
+/* Okay, not at all generic.  Assumes length 9, fix that eventually. */
+{
+	int d, temp, sum;
+	for (d=0; d<length; d+=2) {
+		temp = data[d];
+		sum = 0;
+		sum += (hist[0] + hist[8]) * fir[1];
+		sum += (hist[1] + hist[7]) * fir[2];
+		sum += (hist[2] + hist[6]) * fir[3];
+		sum += (hist[3] + hist[5]) * fir[4];
+		sum +=            hist[4]  * fir[5];
+		data[d] = sum >> 15 ;
+		hist[0] = hist[1];
+		hist[1] = hist[2];
+		hist[2] = hist[3];
+		hist[3] = hist[4];
+		hist[4] = hist[5];
+		hist[5] = hist[6];
+		hist[6] = hist[7];
+		hist[7] = hist[8];
+		hist[8] = temp;
+	}
+}
+
+/* define our own complex math ops
+   because ARMv5 has no hardware float */
+
+void multiply(int ar, int aj, int br, int bj, int *cr, int *cj)
+{
+	*cr = ar*br - aj*bj;
+	*cj = aj*br + ar*bj;
+}
+
+int polar_discriminant(int ar, int aj, int br, int bj)
+{
+	int cr, cj;
+	double angle;
+	multiply(ar, aj, br, -bj, &cr, &cj);
+	angle = atan2((double)cj, (double)cr);
+	return (int)(angle / 3.14159 * (1<<14));
+}
+
+int fast_atan2(int y, int x)
+/* pre scaled for int16 */
+{
+	int yabs, angle;
+	int pi4=(1<<12), pi34=3*(1<<12);  // note pi = 1<<14
+	if (x==0 && y==0) {
+		return 0;
+	}
+	yabs = y;
+	if (yabs < 0) {
+		yabs = -yabs;
+	}
+	if (x >= 0) {
+		angle = pi4  - pi4 * (x-yabs) / (x+yabs);
+	} else {
+		angle = pi34 - pi4 * (x+yabs) / (yabs-x);
+	}
+	if (y < 0) {
+		return -angle;
+	}
+	return angle;
+}
+
+int polar_disc_fast(int ar, int aj, int br, int bj)
+{
+	int cr, cj;
+	multiply(ar, aj, br, -bj, &cr, &cj);
+	return fast_atan2(cj, cr);
+}
+
+int atan_lut_init(void)
+{
+	int i = 0;
+
+	atan_lut = malloc(atan_lut_size * sizeof(int));
+
+	for (i = 0; i < atan_lut_size; i++) {
+		atan_lut[i] = (int) (atan((double) i / (1<<atan_lut_coef)) / 3.14159 * (1<<14));
+	}
+
+	return 0;
+}
+
+int polar_disc_lut(int ar, int aj, int br, int bj)
+{
+	int cr, cj, x, x_abs;
+
+	multiply(ar, aj, br, -bj, &cr, &cj);
+
+	/* special cases */
+	if (cr == 0 || cj == 0) {
+		if (cr == 0 && cj == 0)
+			{return 0;}
+		if (cr == 0 && cj > 0)
+			{return 1 << 13;}
+		if (cr == 0 && cj < 0)
+			{return -(1 << 13);}
+		if (cj == 0 && cr > 0)
+			{return 0;}
+		if (cj == 0 && cr < 0)
+			{return 1 << 14;}
+	}
+
+	/* real range -32768 - 32768 use 64x range -> absolute maximum: 2097152 */
+	x = (cj << atan_lut_coef) / cr;
+	x_abs = abs(x);
+
+	if (x_abs >= atan_lut_size) {
+		/* we can use linear range, but it is not necessary */
+		return (cj > 0) ? 1<<13 : -1<<13;
+	}
+
+	if (x > 0) {
+		return (cj > 0) ? atan_lut[x] : atan_lut[x] - (1<<14);
+	} else {
+		return (cj > 0) ? (1<<14) - atan_lut[-x] : -atan_lut[-x];
+	}
+
+	return 0;
+}
+
+void fm_demod(struct demod_state *fm)
+{
+	int i, pcm;
+	int16_t *lp = fm->lowpassed;
+	pcm = polar_discriminant(lp[0], lp[1],
+		fm->pre_r, fm->pre_j);
+	fm->result[0] = (int16_t)pcm;
+	for (i = 2; i < (fm->lp_len-1); i += 2) {
+		switch (fm->custom_atan) {
+		case 0:
+			pcm = polar_discriminant(lp[i], lp[i+1],
+				lp[i-2], lp[i-1]);
+			break;
+		case 1:
+			pcm = polar_disc_fast(lp[i], lp[i+1],
+				lp[i-2], lp[i-1]);
+			break;
+		case 2:
+			pcm = polar_disc_lut(lp[i], lp[i+1],
+				lp[i-2], lp[i-1]);
+			break;
+		}
+		fm->result[i/2] = (int16_t)pcm;
+	}
+	fm->pre_r = lp[fm->lp_len - 2];
+	fm->pre_j = lp[fm->lp_len - 1];
+	fm->result_len = fm->lp_len/2;
+}
+
+void am_demod(struct demod_state *fm)
+// todo, fix this extreme laziness
+{
+	int i, pcm;
+	int16_t *lp = fm->lowpassed;
+	int16_t *r  = fm->result;
+	for (i = 0; i < fm->lp_len; i += 2) {
+		// hypot uses floats but won't overflow
+		//r[i/2] = (int16_t)hypot(lp[i], lp[i+1]);
+		pcm = lp[i] * lp[i];
+		pcm += lp[i+1] * lp[i+1];
+		r[i/2] = (int16_t)sqrt(pcm) * fm->output_scale;
+	}
+	fm->result_len = fm->lp_len/2;
+	// lowpass? (3khz)  highpass?  (dc)
+}
+
+void usb_demod(struct demod_state *fm)
+{
+	int i, pcm;
+	int16_t *lp = fm->lowpassed;
+	int16_t *r  = fm->result;
+	for (i = 0; i < fm->lp_len; i += 2) {
+		pcm = lp[i] + lp[i+1];
+		r[i/2] = (int16_t)pcm * fm->output_scale;
+	}
+	fm->result_len = fm->lp_len/2;
+}
+
+void lsb_demod(struct demod_state *fm)
+{
+	int i, pcm;
+	int16_t *lp = fm->lowpassed;
+	int16_t *r  = fm->result;
+	for (i = 0; i < fm->lp_len; i += 2) {
+		pcm = lp[i] - lp[i+1];
+		r[i/2] = (int16_t)pcm * fm->output_scale;
+	}
+	fm->result_len = fm->lp_len/2;
+}
+
+void raw_demod(struct demod_state *fm)
+{
+	int i;
+	for (i = 0; i < fm->lp_len; i++) {
+		fm->result[i] = (int16_t)fm->lowpassed[i];
+	}
+	fm->result_len = fm->lp_len;
+}
+
+void deemph_filter(struct demod_state *fm)
+{
+	static int avg;  // cheating...
+	int i, d;
+	// de-emph IIR
+	// avg = avg * (1 - alpha) + sample * alpha;
+	for (i = 0; i < fm->result_len; i++) {
+		d = fm->result[i] - avg;
+		if (d > 0) {
+			avg += (d + fm->deemph_a/2) / fm->deemph_a;
+		} else {
+			avg += (d - fm->deemph_a/2) / fm->deemph_a;
+		}
+		fm->result[i] = (int16_t)avg;
+	}
+}
+
+void dc_block_filter(struct demod_state *fm)
+{
+	int i, avg;
+	int64_t sum = 0;
+	for (i=0; i < fm->result_len; i++) {
+		sum += fm->result[i];
+	}
+	avg = sum / fm->result_len;
+	avg = (avg + fm->dc_avg * 9) / 10;
+	for (i=0; i < fm->result_len; i++) {
+		fm->result[i] -= avg;
+	}
+	fm->dc_avg = avg;
+}
+
+int mad(int16_t *samples, int len, int step)
+/* mean average deviation */
+{
+	int i=0, sum=0, ave=0;
+	if (len == 0)
+		{return 0;}
+	for (i=0; i<len; i+=step) {
+		sum += samples[i];
+	}
+	ave = sum / (len * step);
+	sum = 0;
+	for (i=0; i<len; i+=step) {
+		sum += abs(samples[i] - ave);
+	}
+	return sum / (len / step);
+}
+
+int rms(int16_t *samples, int len, int step)
+/* largely lifted from rtl_power */
+{
+	int i;
+	long p, t, s;
+	double dc, err;
+
+	p = t = 0L;
+	for (i=0; i<len; i+=step) {
+		s = (long)samples[i];
+		t += s;
+		p += s * s;
+	}
+	/* correct for dc offset in squares */
+	dc = (double)(t*step) / (double)len;
+	err = t * 2 * dc - dc * dc * len;
+
+	return (int)sqrt((p-err) / len);
+}
+
+void arbitrary_upsample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* linear interpolation, len1 < len2 */
+{
+	int i = 1;
+	int j = 0;
+	int tick = 0;
+	double frac;  // use integers...
+	while (j < len2) {
+		frac = (double)tick / (double)len2;
+		buf2[j] = (int16_t)(buf1[i-1]*(1-frac) + buf1[i]*frac);
+		j++;
+		tick += len1;
+		if (tick > len2) {
+			tick -= len2;
+			i++;
+		}
+		if (i >= len1) {
+			i = len1 - 1;
+			tick = len2;
+		}
+	}
+}
+
+void arbitrary_downsample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* fractional boxcar lowpass, len1 > len2 */
+{
+	int i = 1;
+	int j = 0;
+	int tick = 0;
+	double remainder = 0;
+	double frac;  // use integers...
+	buf2[0] = 0;
+	while (j < len2) {
+		frac = 1.0;
+		if ((tick + len2) > len1) {
+			frac = (double)(len1 - tick) / (double)len2;}
+		buf2[j] += (int16_t)((double)buf1[i] * frac + remainder);
+		remainder = (double)buf1[i] * (1.0-frac);
+		tick += len2;
+		i++;
+		if (tick > len1) {
+			j++;
+			buf2[j] = 0;
+			tick -= len1;
+		}
+		if (i >= len1) {
+			i = len1 - 1;
+			tick = len1;
+		}
+	}
+	for (j=0; j<len2; j++) {
+		buf2[j] = buf2[j] * len2 / len1;}
+}
+
+void arbitrary_resample(int16_t *buf1, int16_t *buf2, int len1, int len2)
+/* up to you to calculate lengths and make sure it does not go OOB
+ * okay for buffers to overlap, if you are downsampling */
+{
+	if (len1 < len2) {
+		arbitrary_upsample(buf1, buf2, len1, len2);
+	} else {
+		arbitrary_downsample(buf1, buf2, len1, len2);
+	}
+}
+
+void full_demod(struct demod_state *d)
+{
+	int i, ds_p;
+	int sr = 0;
+	ds_p = d->downsample_passes;
+	if (ds_p) {
+		for (i=0; i < ds_p; i++) {
+			fifth_order(d->lowpassed,   (d->lp_len >> i), d->lp_i_hist[i]);
+			fifth_order(d->lowpassed+1, (d->lp_len >> i) - 1, d->lp_q_hist[i]);
+		}
+		d->lp_len = d->lp_len >> ds_p;
+		/* droop compensation */
+		if (d->comp_fir_size == 9 && ds_p <= CIC_TABLE_MAX) {
+			generic_fir(d->lowpassed, d->lp_len,
+				cic_9_tables[ds_p], d->droop_i_hist);
+			generic_fir(d->lowpassed+1, d->lp_len-1,
+				cic_9_tables[ds_p], d->droop_q_hist);
+		}
+	} else {
+		low_pass(d);
+	}
+	/* power squelch */
+	if (d->squelch_level) {
+		sr = rms(d->lowpassed, d->lp_len, 1);
+		if (sr < d->squelch_level) {
+			d->squelch_hits++;
+			for (i=0; i< d->lp_len; i++) {
+				d->lowpassed[i] = 0;
+			}
+		} else {
+			d->squelch_hits = 0;
+		}
+	}
+	d->mode_demod(d);  /* lowpassed -> result */
+	if (d->mode_demod == &raw_demod) {
+		return;
+	}
+	/* todo, fm noise squelch */
+	// use nicer filter here too?
+	if (d->post_downsample > 1) {
+		d->result_len = low_pass_simple(d->result, d->result_len, d->post_downsample);}
+	if (d->deemph) {
+		deemph_filter(d);}
+	if (d->dc_block) {
+		dc_block_filter(d);}
+	if (d->rate_out2 > 0) {
+		low_pass_real(d);
+		//arbitrary_resample(d->result, d->result, d->result_len, d->result_len * d->rate_out2 / d->rate_out);
+	}
+}
+
+static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
+{
+	int i;
+	struct dongle_state *s = ctx;
+	struct demod_state *d = s->demod_target;
+
+	if (do_exit) {
+		return;}
+	if (!ctx) {
+		return;}
+	if (s->mute) {
+		for (i=0; i<s->mute; i++) {
+			buf[i] = 127;}
+		s->mute = 0;
+	}
+	if (!s->offset_tuning) {
+		rotate_90(buf, len);}
+	for (i=0; i<(int)len; i++) {
+		s->buf16[i] = (int16_t)buf[i] - 127;}
+	pthread_rwlock_wrlock(&d->rw);
+	memcpy(d->lowpassed, s->buf16, 2*len);
+	d->lp_len = len;
+	pthread_rwlock_unlock(&d->rw);
+	safe_cond_signal(&d->ready, &d->ready_m);
+}
+
+static void *dongle_thread_fn(void *arg)
+{
+	struct dongle_state *s = arg;
+	fprintf(stderr, "dongle_thread_fn running\n");
+	rtlsdr_read_async(s->dev, rtlsdr_callback, s, 0, s->buf_len);
+	fprintf(stderr, "dongle_thread_fn exited!\n");
+	return 0;
+}
+
+static void rtl_fm_scan_callback(void)
+{
+	struct controller_state *s = &controller;
+	uint32_t frequency = rtl_fm_get_freq();
+
+	if(!s->scanning)
+		return;
+
+	if(!s->scan_direction) {
+		frequency += s->scan_step;
+		if(frequency > s->scan_max)
+			frequency = s->scan_min;
+	} else {
+		frequency -= s->scan_step;
+		if(frequency < s->scan_min)
+			frequency = s->scan_max;
+	}
+
+	rtl_fm_set_freq(frequency);
+}
+
+static void rtl_fm_scan_end_callback(void)
+{
+	struct controller_state *s = &controller;
+
+	if(!s->scanning)
+		return;
+
+	rtl_fm_scan_stop();
+
+	if(s->scan_callback)
+		s->scan_callback(rtl_fm_get_freq(), s->scan_callback_data);
+}
+
+static void *demod_thread_fn(void *arg)
+{
+	struct demod_state *d = arg;
+	struct output_state *o = d->output_target;
+	fprintf(stderr, "demod_thread_fn running\n");
+	while (!do_exit) {
+		safe_cond_wait(&d->ready, &d->ready_m);
+		pthread_rwlock_wrlock(&d->rw);
+		full_demod(d);
+		pthread_rwlock_unlock(&d->rw);
+		if (d->exit_flag) {
+			do_exit = 1;
+		}
+		if (d->squelch_level) {
+			if(d->squelch_hits > d->conseq_squelch) {
+				d->squelch_hits = d->conseq_squelch + 1;  /* hair trigger */
+				//safe_cond_signal(&controller.hop, &controller.hop_m);
+				rtl_fm_scan_callback();
+				continue;
+			} else if(!d->squelch_hits) {
+				rtl_fm_scan_end_callback();
+			}
+		}
+		pthread_rwlock_wrlock(&o->rw);
+		memcpy(o->result, d->result, 2*d->result_len);
+		o->result_len = d->result_len;
+		pthread_rwlock_unlock(&o->rw);
+		safe_cond_signal(&o->ready, &o->ready_m);
+	}
+	fprintf(stderr, "demod_thread_fn exited!\n");
+	return 0;
+}
+
+static void *output_thread_fn(void *arg)
+{
+	struct output_state *s = arg;
+	fprintf(stderr, "output_thread_fn running\n");
+	while (!do_exit) {
+		// use timedwait and pad out under runs
+		safe_cond_wait(&s->ready, &s->ready_m);
+		pthread_rwlock_rdlock(&s->rw);
+		if(s->output_fn) {
+			s->output_fn(s->result, s->result_len, s->output_fn_data);
+		}
+		pthread_rwlock_unlock(&s->rw);
+	}
+	fprintf(stderr, "output_thread_fn exited!\n");
+	return 0;
+}
+
+static void optimal_settings(int freq, int rate)
+{
+	// giant ball of hacks
+	// seems unable to do a single pass, 2:1
+	int capture_freq, capture_rate;
+	struct dongle_state *d = &dongle;
+	struct demod_state *dm = &demod;
+	struct controller_state *cs = &controller;
+	dm->downsample = (1000000 / dm->rate_in) + 1;
+	if (dm->downsample_passes) {
+		dm->downsample_passes = (int)log2(dm->downsample) + 1;
+		dm->downsample = 1 << dm->downsample_passes;
+	}
+	capture_freq = freq;
+	capture_rate = dm->downsample * dm->rate_in;
+	if (!d->offset_tuning) {
+		capture_freq = freq + capture_rate/4;}
+	capture_freq += cs->edge * dm->rate_in / 2;
+	dm->output_scale = (1<<15) / (128 * dm->downsample);
+	if (dm->output_scale < 1) {
+		dm->output_scale = 1;}
+	if (dm->mode_demod == &fm_demod) {
+		dm->output_scale = 1;}
+	d->freq = (uint32_t)capture_freq;
+	d->rate = (uint32_t)capture_rate;
+}
+
+
+void frequency_range(struct controller_state *s, char *arg)
+{
+	char *start, *stop, *step;
+	int i;
+	start = arg;
+	stop = strchr(start, ':') + 1;
+	stop[-1] = '\0';
+	step = strchr(stop, ':') + 1;
+	step[-1] = '\0';
+	for(i=(int)atofs(start); i<=(int)atofs(stop); i+=(int)atofs(step))
+	{
+		s->freqs[s->freq_len] = (uint32_t)i;
+		s->freq_len++;
+		if (s->freq_len >= FREQUENCIES_LIMIT) {
+			break;}
+	}
+	stop[-1] = ':';
+	step[-1] = ':';
+}
+
+void dongle_init(struct dongle_state *s)
+{
+	s->rate = DEFAULT_SAMPLE_RATE;
+	s->gain = AUTO_GAIN; // tenths of a dB
+	s->mute = 0;
+	s->direct_sampling = 0;
+	s->offset_tuning = 0;
+	s->demod_target = &demod;
+}
+
+void demod_init(struct demod_state *s)
+{
+	s->rate_in = DEFAULT_SAMPLE_RATE;
+	s->rate_out = DEFAULT_SAMPLE_RATE;
+	s->squelch_level = 0;
+	s->conseq_squelch = DEFAULT_CONSEQ_SQUELCH;
+	s->terminate_on_squelch = 0;
+	s->squelch_hits = DEFAULT_CONSEQ_SQUELCH + 1;
+	s->downsample_passes = 0;
+	s->comp_fir_size = 0;
+	s->prev_index = 0;
+	s->post_downsample = 1;  // once this works, default = 4
+	s->custom_atan = 0;
+	s->deemph = 0;
+	s->rate_out2 = -1;  // flag for disabled
+	s->mode_demod = &fm_demod;
+	s->pre_j = s->pre_r = s->now_r = s->now_j = 0;
+	s->prev_lpr_index = 0;
+	s->deemph_a = 0;
+	s->now_lpr = 0;
+	s->dc_block = 0;
+	s->dc_avg = 0;
+	pthread_rwlock_init(&s->rw, NULL);
+	pthread_cond_init(&s->ready, NULL);
+	pthread_mutex_init(&s->ready_m, NULL);
+	s->output_target = &output;
+}
+
+void demod_cleanup(struct demod_state *s)
+{
+	pthread_rwlock_destroy(&s->rw);
+	pthread_cond_destroy(&s->ready);
+	pthread_mutex_destroy(&s->ready_m);
+}
+
+void output_init(struct output_state *s)
+{
+	s->rate = DEFAULT_SAMPLE_RATE;
+	s->output_fn = NULL;
+	s->output_fn_data = NULL;
+	pthread_rwlock_init(&s->rw, NULL);
+	pthread_cond_init(&s->ready, NULL);
+	pthread_mutex_init(&s->ready_m, NULL);
+}
+
+void output_cleanup(struct output_state *s)
+{
+	pthread_rwlock_destroy(&s->rw);
+	pthread_cond_destroy(&s->ready);
+	pthread_mutex_destroy(&s->ready_m);
+}
+
+void controller_init(struct controller_state *s)
+{
+	s->freqs[0] = 100000000;
+	s->freq_len = 0;
+	s->edge = 0;
+	s->wb_mode = 0;
+	pthread_cond_init(&s->hop, NULL);
+	pthread_mutex_init(&s->hop_m, NULL);
+}
+
+void controller_cleanup(struct controller_state *s)
+{
+	pthread_cond_destroy(&s->hop);
+	pthread_mutex_destroy(&s->hop_m);
+}
+
+void sanity_checks(void)
+{
+	if (controller.freq_len == 0) {
+		fprintf(stderr, "Please specify a frequency.\n");
+		exit(1);
+	}
+
+	if (controller.freq_len >= FREQUENCIES_LIMIT) {
+		fprintf(stderr, "Too many channels, maximum %i.\n", FREQUENCIES_LIMIT);
+		exit(1);
+	}
+
+	if (controller.freq_len > 1 && demod.squelch_level == 0) {
+		fprintf(stderr, "Please specify a squelch level.  Required for scanning multiple frequencies.\n");
+		exit(1);
+	}
+
+}
+
+int rtl_fm_init(uint32_t freq,
+		uint32_t sample_rate,
+		uint32_t resample_rate,
+		rtl_fm_output_fn_t output_fn,
+		void *output_fn_data)
+{
+	int r = 0;
+
+	dongle_init(&dongle);
+	demod_init(&demod);
+	output_init(&output);
+	controller_init(&controller);
+
+	/*
+	 * Simulate the effects of command line arguments:
+	 *
+	 * -W wbfm -s <sample rate> -r <resample rate>
+	 */
+
+	/* Set initial frequency */
+	controller.freqs[0] = freq;
+	controller.freq_len++;
+
+	/* Set mode to wbfm */
+	controller.wb_mode = 1;
+	demod.mode_demod = &fm_demod;
+	demod.rate_in = 170000;
+	demod.rate_out = 170000;
+	demod.rate_out2 = 32000;
+	demod.custom_atan = 1;
+	//demod.post_downsample = 4;
+	demod.deemph = 1;
+	controller.scan_squelch_count = DEFAULT_CONSEQ_SQUELCH;
+	controller.scan_squelch_level = DEFAULT_SQUELCH_LEVEL;
+	demod.squelch_level = 0;
+
+	/* Adjust frequency for wb mode */
+	controller.freqs[0] += 16000;
+
+	/* Set sample rate */
+	demod.rate_in = sample_rate;
+	demod.rate_out = sample_rate;
+
+	/* Set resample rate */
+	output.rate = (int) resample_rate;
+	demod.rate_out2 = (int) resample_rate;
+
+	/* Set output function pointer */
+	if(output_fn) {
+		output.output_fn = output_fn;
+		output.output_fn_data = output_fn_data;
+	}
+
+	/* quadruple sample_rate to limit to Δθ to ±π/2 */
+	demod.rate_in *= demod.post_downsample;
+
+	if (!output.rate) {
+		output.rate = demod.rate_out;
+	}
+
+	sanity_checks();
+
+	if (controller.freq_len > 1) {
+		demod.terminate_on_squelch = 0;
+	}
+
+	ACTUAL_BUF_LENGTH = lcm_post[demod.post_downsample] * DEFAULT_BUF_LENGTH;
+
+	dongle.dev_index = verbose_device_search("0");
+	if (dongle.dev_index < 0) {
+		return -1;
+	}
+
+	r = rtlsdr_open(&dongle.dev, (uint32_t)dongle.dev_index);
+	if (r < 0) {
+		fprintf(stderr, "Failed to open rtlsdr device #%d.\n", dongle.dev_index);
+		return r;
+	}
+
+	if (demod.deemph) {
+		demod.deemph_a = (int)round(1.0/((1.0-exp(-1.0/(demod.rate_out * 75e-6)))));
+	}
+
+	/* Set the tuner gain */
+	if (dongle.gain == AUTO_GAIN) {
+		verbose_auto_gain(dongle.dev);
+	} else {
+		dongle.gain = nearest_gain(dongle.dev, dongle.gain);
+		verbose_gain_set(dongle.dev, dongle.gain);
+	}
+
+	verbose_ppm_set(dongle.dev, dongle.ppm_error);
+
+	//r = rtlsdr_set_testmode(dongle.dev, 1);
+
+	return r;
+}
+
+void rtl_fm_start(void)
+{
+	struct controller_state *s = &controller;
+
+	/*
+	 * A bunch of the following is pulled from the controller_thread_fn,
+	 * which has been removed.
+	 */
+
+	/* Reset endpoint before we start reading from it (mandatory) */
+	verbose_reset_buffer(dongle.dev);
+
+	/* set up primary channel */
+	optimal_settings(s->freqs[0], demod.rate_in);
+	if (dongle.direct_sampling) {
+		verbose_direct_sampling(dongle.dev, 1);}
+	if (dongle.offset_tuning) {
+		verbose_offset_tuning(dongle.dev);}
+
+	/* Set the frequency */
+	verbose_set_frequency(dongle.dev, dongle.freq);
+	fprintf(stderr, "Oversampling input by: %ix.\n", demod.downsample);
+	fprintf(stderr, "Oversampling output by: %ix.\n", demod.post_downsample);
+	fprintf(stderr, "Buffer size: %0.2fms\n",
+		1000 * 0.5 * (float)ACTUAL_BUF_LENGTH / (float)dongle.rate);
+
+	/* Set the sample rate */
+	verbose_set_sample_rate(dongle.dev, dongle.rate);
+	fprintf(stderr, "Output at %u Hz.\n", demod.rate_in/demod.post_downsample);
+	usleep(100000);
+
+	rtl_fm_scan_stop();
+
+	do_exit = 0;
+	pthread_create(&output.thread, NULL, output_thread_fn, (void *)(&output));
+	pthread_create(&demod.thread, NULL, demod_thread_fn, (void *)(&demod));
+	pthread_create(&dongle.thread, NULL, dongle_thread_fn, (void *)(&dongle));
+}
+
+void rtl_fm_set_freq(uint32_t freq)
+{
+	struct controller_state *s = &controller;
+
+	if(s->freqs[0] == freq)
+		return;
+
+	s->freqs[0] = freq;
+	s->freq_len = 1;
+
+	if (s->wb_mode) {
+		s->freqs[0] += 16000;
+	}
+
+	optimal_settings(s->freqs[0], demod.rate_in);
+	if (dongle.offset_tuning) {
+		verbose_offset_tuning(dongle.dev);
+	}
+	rtlsdr_set_center_freq(dongle.dev, dongle.freq);
+
+	// It does not look like refreshing the sample rate is desirable
+	// (e.g. the scanning code in the removed controller thread function
+	// did not do it), and behavior seemed a bit less robust with it
+	// present.  However, I am leaving this here as a reminder to revisit
+	// via some more testing.
+	//rtlsdr_set_sample_rate(dongle.dev, dongle.rate);
+
+	// This triggers a mute during the frequency change
+	dongle.mute = BUFFER_DUMP;
+
+	if(s->freq_callback)
+		s->freq_callback(freq, s->freq_callback_data);
+}
+
+void rtl_fm_set_freq_callback(void (*callback)(uint32_t, void *),
+			      void *data)
+{
+	struct controller_state *s = &controller;
+
+	s->freq_callback = callback;
+	s->freq_callback_data = data;
+}
+
+uint32_t rtl_fm_get_freq(void)
+{
+	struct controller_state *s = &controller;
+	uint32_t frequency = s->freqs[0];
+
+	if (s->wb_mode)
+		frequency -= 16000;
+
+	return frequency;
+}
+
+void rtl_fm_stop(void)
+{
+	rtl_fm_scan_stop();
+
+	rtlsdr_cancel_async(dongle.dev);
+	do_exit = 1;
+	pthread_join(dongle.thread, NULL);
+	safe_cond_signal(&demod.ready, &demod.ready_m);
+	pthread_join(demod.thread, NULL);
+	safe_cond_signal(&output.ready, &output.ready_m);
+	pthread_join(output.thread, NULL);
+}
+
+void rtl_fm_scan_start(int direction,
+		       void (*callback)(uint32_t, void *),
+		       void *data,
+		       uint32_t step,
+		       uint32_t min,
+		       uint32_t max)
+{
+	struct controller_state *s = &controller;
+	struct demod_state *dm = &demod;
+	uint32_t frequency = rtl_fm_get_freq();
+
+	if(s->scanning && s->scan_direction == direction)
+		return;
+
+	s->scanning = 1;
+	s->scan_direction = direction;
+	s->scan_callback = callback;
+	s->scan_callback_data = data;
+	s->scan_step = step;
+	s->scan_min = min;
+	s->scan_max = max;
+
+	/* Start scan by stepping in the desired direction */
+	if(!direction) {
+		frequency += s->scan_step;
+		if(frequency > s->scan_max)
+			frequency = s->scan_min;
+	} else {
+		frequency -= s->scan_step;
+		if(frequency < s->scan_min)
+			frequency = s->scan_max;
+	}
+
+	rtl_fm_set_freq(frequency);
+
+	dm->conseq_squelch = s->scan_squelch_count;
+	dm->squelch_hits = s->scan_squelch_count + 1;
+	dm->squelch_level = s->scan_squelch_level;
+}
+
+void rtl_fm_scan_stop(void)
+{
+	struct controller_state *s = &controller;
+	struct demod_state *dm = &demod;
+
+	s->scanning = 0;
+
+	dm->squelch_hits = s->scan_squelch_count + 1;
+	dm->squelch_level = 0;
+}
+
+void rtl_fm_scan_set_squelch_level(int level)
+{
+	struct controller_state *s = &controller;
+
+	s->scan_squelch_level = level;
+}
+
+void rtl_fm_scan_set_squelch_limit(int count)
+{
+	struct controller_state *s = &controller;
+
+	s->scan_squelch_count = count;
+}
+
+void rtl_fm_cleanup(void)
+{
+	//dongle_cleanup(&dongle);
+	demod_cleanup(&demod);
+	output_cleanup(&output);
+	controller_cleanup(&controller);
+
+	rtlsdr_close(dongle.dev);
+}
+
+// vim: tabstop=8:softtabstop=8:shiftwidth=8:noexpandtab
diff --git a/binding/rtl_fm.h b/binding/rtl_fm.h
new file mode 100644
index 0000000..f5b2a86
--- /dev/null
+++ b/binding/rtl_fm.h
@@ -0,0 +1,70 @@
+/*
+ * rtl-sdr, turns your Realtek RTL2832 based DVB dongle into a SDR receiver
+ * Copyright (C) 2016, 2017 Konsulko Group
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef RTL_FM_H
+#define RTL_FM_H
+
+#include <stdint.h>
+
+#define RTL_FM_DEFAULT_BUF_LENGTH	(1 * 16384)
+#define RTL_FM_MAXIMUM_OVERSAMPLE	16
+#define RTL_FM_MAXIMUM_BUF_LENGTH	(RTL_FM_MAXIMUM_OVERSAMPLE * RTL_FM_DEFAULT_BUF_LENGTH)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef void (*rtl_fm_output_fn_t)(int16_t *result, int result_len, void *data);
+
+int rtl_fm_init(uint32_t freq,
+		uint32_t sample_rate,
+		uint32_t resample_rate,
+		rtl_fm_output_fn_t output_fn,
+		void *output_fn_data);
+
+void rtl_fm_start(void);
+
+void rtl_fm_set_freq(uint32_t freq);
+
+void rtl_fm_set_freq_callback(void (*callback)(uint32_t, void *),
+			      void *data);
+
+uint32_t rtl_fm_get_freq(void);
+
+void rtl_fm_stop(void);
+
+void rtl_fm_scan_start(int direction,
+		       void (*callback)(uint32_t, void *),
+		       void *data,
+		       uint32_t step,
+		       uint32_t min,
+		       uint32_t max);
+
+void rtl_fm_scan_stop(void);
+
+void rtl_fm_scan_set_squelch_level(int level);
+
+void rtl_fm_scan_set_squelch_limit(int count);
+
+void rtl_fm_cleanup(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* RTL_FM_H */