diff options
Diffstat (limited to 'drivers/media/common')
| -rw-r--r-- | drivers/media/common/ir-common.c | 68 |
1 files changed, 67 insertions, 1 deletions
diff --git a/drivers/media/common/ir-common.c b/drivers/media/common/ir-common.c index ab7a1fba4427..a0e700d7a4a4 100644 --- a/drivers/media/common/ir-common.c +++ b/drivers/media/common/ir-common.c @@ -1,5 +1,4 @@ /* - * $Id: ir-common.c,v 1.11 2005/07/07 14:44:43 mchehab Exp $ * * some common structs and functions to handle infrared remotes via * input layer ... @@ -335,6 +334,72 @@ int ir_dump_samples(u32 *samples, int count) return 0; } +/* decode raw samples, pulse distance coding used by NEC remotes */ +int ir_decode_pulsedistance(u32 *samples, int count, int low, int high) +{ + int i,last,bit,len; + u32 curBit; + u32 value; + + /* find start burst */ + for (i = len = 0; i < count * 32; i++) { + bit = getbit(samples,i); + if (bit) { + len++; + } else { + if (len >= 29) + break; + len = 0; + } + } + + /* start burst to short */ + if (len < 29) + return 0xffffffff; + + /* find start silence */ + for (len = 0; i < count * 32; i++) { + bit = getbit(samples,i); + if (bit) { + break; + } else { + len++; + } + } + + /* silence to short */ + if (len < 7) + return 0xffffffff; + + /* go decoding */ + len = 0; + last = 1; + value = 0; curBit = 1; + for (; i < count * 32; i++) { + bit = getbit(samples,i); + if (last) { + if(bit) { + continue; + } else { + len = 1; + } + } else { + if (bit) { + if (len > (low + high) /2) + value |= curBit; + curBit <<= 1; + if (curBit == 1) + break; + } else { + len++; + } + } + last = bit; + } + + return value; +} + /* decode raw samples, biphase coding, used by rc5 for example */ int ir_decode_biphase(u32 *samples, int count, int low, int high) { @@ -383,6 +448,7 @@ EXPORT_SYMBOL_GPL(ir_input_keydown); EXPORT_SYMBOL_GPL(ir_extract_bits); EXPORT_SYMBOL_GPL(ir_dump_samples); EXPORT_SYMBOL_GPL(ir_decode_biphase); +EXPORT_SYMBOL_GPL(ir_decode_pulsedistance); /* * Local variables: |