Improve radio RDS driver and framework

* Remove unused bits like the radio event and simplify basic
radio interface. It can be more self-contained with rds.h only
required by radio and tuner code.

* Add post-processing to text a-la Silicon Labs AN243. The chip's
error correction can only do so much; additional checks are highly
recommended. Simply testing for two identical messages in a row
is extremely effective and I've never seen corrupted text since
doing that, even with mediocre reception.

Groups segments must arrive in order, not randomly; logic change
only accepts them in order, starting at 0.

Time readout was made a bit better but really we'd need to use
verbose mode and ensure that no errors were seen during receiving
of time and more checks would be need to have a stable PI. The
text is the important bit anyway.

* Time out of stale text.

* Text is no longer updated until a complete group has been
received, as is specified in the standard. Perhaps go back to
scrolling text lines in the radio screen?

* Add proper character conversion to UTF-8. Only the default G0
table for the moment. The other two could be added in.

* Add variants "RDS_CFG_PROCESS" and "RDS_CFG_PUSH" to allow
the option for processed RDS data to be pushed to the driver and
still do proper post-processing (only text conversion for now for
the latter).

Change-Id: I4d83f8b2e89a209a5096d15ec266477318c66925

1 files changed, 13 insertions, 6 deletions

diff --git a/firmware/export/tuner.h b/firmware/export/tuner.h
index 050bbd0..a166eac 100644
--- a/firmware/export/tuner.h
+++ b/firmware/export/tuner.h
@@ -25,6 +25,10 @@
 #include "config.h"
 #include "hwcompat.h"
 
+#ifdef HAVE_RDS_CAP
+#include <sys/types.h>
+#endif
+
 /** Settings to the tuner layer **/
 enum
 {
@@ -45,8 +49,6 @@ enum
     RADIO_PRESENT = 0,
     RADIO_TUNED,
     RADIO_STEREO,
-    /* RADIO_EVENT is an event that requests a screen update */
-    RADIO_EVENT,
     RADIO_RSSI,
     RADIO_RSSI_MIN,
     RADIO_RSSI_MAX,
@@ -57,15 +59,20 @@ enum
 
 #ifdef HAVE_RDS_CAP
 /** Readback from the tuner RDS layer **/
-enum
+/* returns needed size if buffer size is inadequate */
+size_t tuner_get_rds_info(int setting, void *dst, size_t dstsize);
+
+enum RADIO_RDS_INFO
 {
-    RADIO_RDS_NAME,
-    RADIO_RDS_TEXT,
+    RADIO_RDS_NAME,         /* dst: array of char, dstsize: buffer size */
+    RADIO_RDS_TEXT,         /* dst: array of char, dstsize: buffer size */
+    RADIO_RDS_PROGRAM_INFO, /* dst: uint16_t *, dstsize: >= sizeof(uint16_t) */
+    RADIO_RDS_CURRENT_TIME, /* dst: time_t *, dstsize: >= sizeof(time_t) */
 
     /* Put new general-purpose readback values above this line */
     __RADIO_GET_RDS_INFO_STANDARD_LAST
 };
-#endif
+#endif /* HAVE_RDS_CAP */
 
 /** Tuner regions **/