[media] rc: ir-rc6-decoder: Add encode capability

Add the capability to encode RC-6 and RC-6A scancodes as raw events.

The Manchester modulation helper is used several times with various
timings so that RC-6 header preamble, the header, header trailing bit
and the data itself can be modulated correctly.

Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Cc: James Hogan <james@albanarts.com>
Cc: David Härdeman <david@hardeman.nu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/rc/ir-rc6-decoder.c b/drivers/media/rc/ir-rc6-decoder.c
index 5cc54c9..6fe2268 100644 (file)
--- a/drivers/media/rc/ir-rc6-decoder.c
+++ b/drivers/media/rc/ir-rc6-decoder.c
@@ -286,11 +286,128 @@ out:
        return -EINVAL;
 }
 
+static const struct ir_raw_timings_manchester ir_rc6_timings[4] = {
+       {
+               .leader                 = RC6_PREFIX_PULSE,
+               .pulse_space_start      = 0,
+               .clock                  = RC6_UNIT,
+               .invert                 = 1,
+               .trailer_space          = RC6_PREFIX_SPACE,
+       },
+       {
+               .clock                  = RC6_UNIT,
+               .invert                 = 1,
+       },
+       {
+               .clock                  = RC6_UNIT * 2,
+               .invert                 = 1,
+       },
+       {
+               .clock                  = RC6_UNIT,
+               .invert                 = 1,
+               .trailer_space          = RC6_SUFFIX_SPACE,
+       },
+};
+
+/**
+ * ir_rc6_encode() - Encode a scancode as a stream of raw events
+ *
+ * @protocol:  protocol to encode
+ * @scancode:  scancode to encode
+ * @events:    array of raw ir events to write into
+ * @max:       maximum size of @events
+ *
+ * Returns:    The number of events written.
+ *             -ENOBUFS if there isn't enough space in the array to fit the
+ *             encoding. In this case all @max events will have been written.
+ *             -EINVAL if the scancode is ambiguous or invalid.
+ */
+static int ir_rc6_encode(enum rc_type protocol, u32 scancode,
+                        struct ir_raw_event *events, unsigned int max)
+{
+       int ret;
+       struct ir_raw_event *e = events;
+
+       if (protocol == RC_TYPE_RC6_0) {
+               /* Modulate the preamble */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc6_timings[0], 0, 0);
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate the header (Start Bit & Mode-0) */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[1],
+                                           RC6_HEADER_NBITS, (1 << 3));
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate Trailer Bit */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[2], 1, 0);
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate rest of the data */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[3], RC6_0_NBITS,
+                                           scancode);
+               if (ret < 0)
+                       return ret;
+
+       } else {
+               int bits;
+
+               switch (protocol) {
+               case RC_TYPE_RC6_MCE:
+               case RC_TYPE_RC6_6A_32:
+                       bits = 32;
+                       break;
+               case RC_TYPE_RC6_6A_24:
+                       bits = 24;
+                       break;
+               case RC_TYPE_RC6_6A_20:
+                       bits = 20;
+                       break;
+               default:
+                       return -EINVAL;
+               }
+
+               /* Modulate the preamble */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc6_timings[0], 0, 0);
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate the header (Start Bit & Header-version 6 */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[1],
+                                           RC6_HEADER_NBITS, (1 << 3 | 6));
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate Trailer Bit */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[2], 1, 0);
+               if (ret < 0)
+                       return ret;
+
+               /* Modulate rest of the data */
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc6_timings[3],
+                                           bits,
+                                           scancode);
+               if (ret < 0)
+                       return ret;
+       }
+
+       return e - events;
+}
+
 static struct ir_raw_handler rc6_handler = {
        .protocols      = RC_BIT_RC6_0 | RC_BIT_RC6_6A_20 |
                          RC_BIT_RC6_6A_24 | RC_BIT_RC6_6A_32 |
                          RC_BIT_RC6_MCE,
        .decode         = ir_rc6_decode,
+       .encode         = ir_rc6_encode,
 };
 
 static int __init ir_rc6_decode_init(void)