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: