[media] rc: ir-rc5-decoder: Add encode capability

Add the capability to encode RC-5, RC-5X and RC-5-SZ scancodes as raw
events.

The Manchester modulation helper is used, and for RC-5X it is used twice
with two sets of timings, the first with a short trailer space for the
space in the middle, and the second with no leader so that it can
continue the space.

The encoding in RC-5-SZ first inserts a pulse and then simply utilizes
the generic Manchester encoder available in rc-core.

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

diff --git a/drivers/media/rc/ir-rc5-decoder.c b/drivers/media/rc/ir-rc5-decoder.c
index 484185e5248d9a4ecbc42959732253a950c90565..fcfedf95def72a3dc9ffdd70d2a025210b8ea26f 100644 (file)
--- a/drivers/media/rc/ir-rc5-decoder.c
+++ b/drivers/media/rc/ir-rc5-decoder.c
@@ -181,9 +181,106 @@ static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev)
        return -EINVAL;
 }
 
+static const struct ir_raw_timings_manchester ir_rc5_timings = {
+       .leader                 = RC5_UNIT,
+       .pulse_space_start      = 0,
+       .clock                  = RC5_UNIT,
+       .trailer_space          = RC5_UNIT * 10,
+};
+
+static const struct ir_raw_timings_manchester ir_rc5x_timings[2] = {
+       {
+               .leader                 = RC5_UNIT,
+               .pulse_space_start      = 0,
+               .clock                  = RC5_UNIT,
+               .trailer_space          = RC5X_SPACE,
+       },
+       {
+               .clock                  = RC5_UNIT,
+               .trailer_space          = RC5_UNIT * 10,
+       },
+};
+
+static const struct ir_raw_timings_manchester ir_rc5_sz_timings = {
+       .leader                         = RC5_UNIT,
+       .pulse_space_start              = 0,
+       .clock                          = RC5_UNIT,
+       .trailer_space                  = RC5_UNIT * 10,
+};
+
+/**
+ * ir_rc5_encode() - Encode a scancode as a stream of raw events
+ *
+ * @protocol:  protocol variant 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_rc5_encode(enum rc_type protocol, u32 scancode,
+                        struct ir_raw_event *events, unsigned int max)
+{
+       int ret;
+       struct ir_raw_event *e = events;
+       unsigned int data, xdata, command, commandx, system, pre_space_data;
+
+       /* Detect protocol and convert scancode to raw data */
+       if (protocol == RC_TYPE_RC5) {
+               /* decode scancode */
+               command  = (scancode & 0x003f) >> 0;
+               commandx = (scancode & 0x0040) >> 6;
+               system   = (scancode & 0x1f00) >> 8;
+               /* encode data */
+               data = !commandx << 12 | system << 6 | command;
+
+               /* Modulate the data */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5_timings,
+                                           RC5_NBITS, data);
+               if (ret < 0)
+                       return ret;
+       } else if (protocol == RC_TYPE_RC5X_20) {
+               /* decode scancode */
+               xdata    = (scancode & 0x00003f) >> 0;
+               command  = (scancode & 0x003f00) >> 8;
+               commandx = !(scancode & 0x004000);
+               system   = (scancode & 0x1f0000) >> 16;
+
+               /* encode data */
+               data = commandx << 18 | system << 12 | command << 6 | xdata;
+
+               /* Modulate the data */
+               pre_space_data = data >> (RC5X_NBITS - CHECK_RC5X_NBITS);
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5x_timings[0],
+                                           CHECK_RC5X_NBITS, pre_space_data);
+               if (ret < 0)
+                       return ret;
+               ret = ir_raw_gen_manchester(&e, max - (e - events),
+                                           &ir_rc5x_timings[1],
+                                           RC5X_NBITS - CHECK_RC5X_NBITS,
+                                           data);
+               if (ret < 0)
+                       return ret;
+       } else if (protocol == RC_TYPE_RC5_SZ) {
+               /* RC5-SZ scancode is raw enough for Manchester as it is */
+               ret = ir_raw_gen_manchester(&e, max, &ir_rc5_sz_timings,
+                                           RC5_SZ_NBITS, scancode & 0x2fff);
+               if (ret < 0)
+                       return ret;
+       } else {
+               return -EINVAL;
+       }
+
+       return e - events;
+}
+
 static struct ir_raw_handler rc5_handler = {
        .protocols      = RC_BIT_RC5 | RC_BIT_RC5X_20 | RC_BIT_RC5_SZ,
        .decode         = ir_rc5_decode,
+       .encode         = ir_rc5_encode,
 };
 
 static int __init ir_rc5_decode_init(void)