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path: root/drivers/media/common/ir-common.c
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Diffstat (limited to 'drivers/media/common/ir-common.c')
-rw-r--r--drivers/media/common/ir-common.c68
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: