Add Kingfisher Si4689 support

Add conditionally compilable support for the Si4689 radio on the
M3ULCB Kingfisher infotainment board.  The codebase has been
refactored to allow multiple radio implementations, and when
Kingfisher support is enabled, the binding will first look for a
USB RTL-SDR adapter, then fallback to the Kingfisher Si4689 if
one is not found.  This allows easily switching to a RTL-SDR
adapter if this initial Kingfisher support encounters issues.

The back end implementation relies on a patched version of the
"si_ctl" utility from Cogent Embedded's Kingfisher BSP changes.
The modifications to it add FM band plan selection and scanning
threshold tweaking for poor radio environments.  Audio output is
achieved by looping the radio's PulseAudio source to the
appropriate sink depending on 4A or non-4A operation.  For 4A
compatibility, the PulseAudio source is created if it does not
exist, which currently is the case due to PulseAudio's udev
module being disabled when 4A is enabled.

Additionally, the FM band plan for Japan has been corrected to go
to 95 MHz, and a README.md file has been added documenting the
optional configuration that can be done via /etc/xdg/AGL.conf for
band plan selection and scanning sensitivity.

Change-Id: I204906fed741d917fc3b8be962deadb4e59989db
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Signed-off-by: Harunobu Kurokawa <harunobu.kurokawa.dn@renesas.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/binding/radio_impl_rtlsdr.h b/binding/radio_impl_rtlsdr.h
new file mode 100644
index 0000000..6c83338
--- /dev/null
+++ b/binding/radio_impl_rtlsdr.h
@@ -0,0 +1,25 @@
+/*
+ * 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_RTLSDR_H
+#define _RADIO_IMPL_RTLSDR_H
+
+#include "radio_impl.h"
+
+extern radio_impl_ops_t rtlsdr_impl_ops;
+
+#endif /* _RADIO_IMPL_RTLSDR_H */
+