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

Add the capability to encode NEC scancodes as raw events. The
scancode_to_raw is pretty much taken from the img-ir NEC filter()
callback, and modulation uses the pulse distance helper added in a
previous commit.

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

diff --git a/drivers/media/rc/ir-nec-decoder.c b/drivers/media/rc/ir-nec-decoder.c
index a5d418e..3ce8503 100644 (file)
--- a/drivers/media/rc/ir-nec-decoder.c
+++ b/drivers/media/rc/ir-nec-decoder.c
@@ -204,9 +204,90 @@ static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev)
        return -EINVAL;
 }
 
+/**
+ * ir_nec_scancode_to_raw() - encode an NEC scancode ready for modulation.
+ * @protocol:  specific protocol to use
+ * @scancode:  a single NEC scancode.
+ * @raw:       raw data to be modulated.
+ */
+static u32 ir_nec_scancode_to_raw(enum rc_type protocol, u32 scancode)
+{
+       unsigned int addr, addr_inv, data, data_inv;
+
+       data = scancode & 0xff;
+
+       if (protocol == RC_TYPE_NEC32) {
+               /* 32-bit NEC (used by Apple and TiVo remotes) */
+               /* scan encoding: aaAAddDD */
+               addr_inv   = (scancode >> 24) & 0xff;
+               addr       = (scancode >> 16) & 0xff;
+               data_inv   = (scancode >>  8) & 0xff;
+       } else if (protocol == RC_TYPE_NECX) {
+               /* Extended NEC */
+               /* scan encoding AAaaDD */
+               addr       = (scancode >> 16) & 0xff;
+               addr_inv   = (scancode >>  8) & 0xff;
+               data_inv   = data ^ 0xff;
+       } else {
+               /* Normal NEC */
+               /* scan encoding: AADD */
+               addr       = (scancode >>  8) & 0xff;
+               addr_inv   = addr ^ 0xff;
+               data_inv   = data ^ 0xff;
+       }
+
+       /* raw encoding: ddDDaaAA */
+       return data_inv << 24 |
+              data     << 16 |
+              addr_inv <<  8 |
+              addr;
+}
+
+static const struct ir_raw_timings_pd ir_nec_timings = {
+       .header_pulse   = NEC_HEADER_PULSE,
+       .header_space   = NEC_HEADER_SPACE,
+       .bit_pulse      = NEC_BIT_PULSE,
+       .bit_space[0]   = NEC_BIT_0_SPACE,
+       .bit_space[1]   = NEC_BIT_1_SPACE,
+       .trailer_pulse  = NEC_TRAILER_PULSE,
+       .trailer_space  = NEC_TRAILER_SPACE,
+       .msb_first      = 0,
+};
+
+/**
+ * ir_nec_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.
+ */
+static int ir_nec_encode(enum rc_type protocol, u32 scancode,
+                        struct ir_raw_event *events, unsigned int max)
+{
+       struct ir_raw_event *e = events;
+       int ret;
+       u32 raw;
+
+       /* Convert a NEC scancode to raw NEC data */
+       raw = ir_nec_scancode_to_raw(protocol, scancode);
+
+       /* Modulate the raw data using a pulse distance modulation */
+       ret = ir_raw_gen_pd(&e, max, &ir_nec_timings, NEC_NBITS, raw);
+       if (ret < 0)
+               return ret;
+
+       return e - events;
+}
+
 static struct ir_raw_handler nec_handler = {
        .protocols      = RC_BIT_NEC | RC_BIT_NECX | RC_BIT_NEC32,
        .decode         = ir_nec_decode,
+       .encode         = ir_nec_encode,
 };
 
 static int __init ir_nec_decode_init(void)