V4L/DVB: saa7134: don't wait too much to generate an IR event on raw_decode

At raw_decode mode, the key is processed after the end of a timer. The
previous code resets the timer every time something is received at the IR
port. While this works fine with IR's that don't implement repeat, like
Avermedia RM-JX IR, it keeps waiting until keydown, on IR's that implement
NEC repeat command, like the Terratec yellow.

The solution is to change the behaviour to do the timeout after the first
received data.

The timeout is currently set to 15 ms, as it works fine with NEC protcocol.
It may need some adjustments to support other protocols and to better handle
spurious detections that may happen with some IR sensors.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 83 insertions, 39 deletions

diff --git a/drivers/media/IR/ir-nec-decoder.c b/drivers/media/IR/ir-nec-decoder.c
index a58c717ec6b0..104482a6991e 100644
--- a/drivers/media/IR/ir-nec-decoder.c
+++ b/drivers/media/IR/ir-nec-decoder.c
@@ -14,21 +14,51 @@
 
 #include <media/ir-core.h>
 
-/* Start time: 4.5 ms  */
-#define MIN_START_TIME  3900000
-#define MAX_START_TIME  5100000
+/* Start time: 4.5 ms + 560 us of the next pulse */
+#define MIN_START_TIME  (3900000 + 560000)
+#define MAX_START_TIME  (5100000 + 560000)
 
-/* Pulse time: 560 us  */
-#define MIN_PULSE_TIME  460000
-#define MAX_PULSE_TIME  660000
+/* Bit 1 time: 2.25ms us */
+#define MIN_BIT1_TIME   2050000
+#define MAX_BIT1_TIME   2450000
 
-/* Bit 1 space time: 2.25ms-560 us */
-#define MIN_BIT1_TIME   1490000
-#define MAX_BIT1_TIME   1890000
+/* Bit 0 time: 1.12ms us */
+#define MIN_BIT0_TIME   920000
+#define MAX_BIT0_TIME   1320000
 
-/* Bit 0 space time: 1.12ms-560 us */
-#define MIN_BIT0_TIME   360000
-#define MAX_BIT0_TIME   760000
+/* Total IR code is 110 ms, including the 9 ms for the start pulse */
+#define MAX_NEC_TIME    4000000
+
+/* Total IR code is 110 ms, including the 9 ms for the start pulse */
+#define MIN_REPEAT_TIME 99000000
+#define MAX_REPEAT_TIME 112000000
+
+/* Repeat time: 2.25ms us */
+#define MIN_REPEAT_START_TIME   2050000
+#define MAX_REPEAT_START_TIME   3000000
+
+#define REPEAT_TIME     240 /* ms */
+
+/** is_repeat - Check if it is a NEC repeat event
+ * @input_dev:  the struct input_dev descriptor of the device
+ * @pos:        the position of the first event
+ * @len:        the length of the buffer
+ */
+static int is_repeat(struct ir_raw_event *evs, int len, int pos)
+{
+        if ((evs[pos].delta.tv_nsec < MIN_REPEAT_START_TIME) ||
+            (evs[pos].delta.tv_nsec > MAX_REPEAT_START_TIME))
+                return 0;
+
+        if (++pos >= len)
+                return 0;
+
+        if ((evs[pos].delta.tv_nsec < MIN_REPEAT_TIME) ||
+            (evs[pos].delta.tv_nsec > MAX_REPEAT_TIME))
+                return 0;
+
+        return 1;
+}
 
 /**
  * __ir_nec_decode() - Decode one NEC pulsecode
@@ -36,49 +66,59 @@
  * @evs:        event array with type/duration of pulse/space
  * @len:        length of the array
  * @pos:        position to start seeking for a code
- * This function returns the decoded ircode or -EINVAL if no pulse got decoded
+ * This function returns -EINVAL if no pulse got decoded,
+ * 0 if buffer is empty and 1 if one keycode were handled.
  */
 static int __ir_nec_decode(struct input_dev *input_dev,
                            struct ir_raw_event *evs,
                            int len, int *pos)
 {
+        struct ir_input_dev *ir = input_get_drvdata(input_dev);
         int count = -1;
         int ircode = 0, not_code = 0;
 
         /* Be sure that the first event is an start one and is a pulse */
         for (; *pos < len; (*pos)++) {
-                if (evs[*pos].type & (IR_START_EVENT | IR_PULSE))
+                /* Very long delays are considered as start events */
+                if (evs[*pos].delta.tv_nsec > MAX_NEC_TIME)
                         break;
-        }
-        (*pos)++;       /* First event doesn't contain data */
+                if (evs[*pos].type & IR_START_EVENT)
+                        break;
+                IR_dprintk(1, "%luus: Spurious NEC %s\n",
+                           (evs[*pos].delta.tv_nsec + 500) / 1000,
+                           (evs[*pos].type & IR_SPACE) ? "space" : "pulse");
 
+        }
         if (*pos >= len)
                 return 0;
 
-        /* First space should have 4.5 ms otherwise is not NEC protocol */
-        if ((evs[*pos].delta.tv_nsec < MIN_START_TIME) |
-            (evs[*pos].delta.tv_nsec > MAX_START_TIME) |
-            (evs[*pos].type != IR_SPACE))
+        (*pos)++;       /* First event doesn't contain data */
+
+        if (evs[*pos].type != IR_PULSE)
                 goto err;
 
-        /*
-         * FIXME: need to implement the repeat sequence
-         */
+        /* Check if it is a NEC repeat event */
+        if (is_repeat(evs, len, *pos)) {
+                *pos += 2;
+                if (ir->keypressed) {
+                        mod_timer(&ir->raw->timer_keyup,
+                                jiffies + msecs_to_jiffies(REPEAT_TIME));
+                        IR_dprintk(1, "NEC repeat event\n");
+                        return 1;
+                } else {
+                        IR_dprintk(1, "missing NEC repeat event\n");
+                        return 0;
+                }
+        }
+
+        /* First space should have 4.5 ms otherwise is not NEC protocol */
+        if ((evs[*pos].delta.tv_nsec < MIN_START_TIME) ||
+            (evs[*pos].delta.tv_nsec > MAX_START_TIME))
+                goto err;
 
         count = 0;
         for ((*pos)++; *pos < len; (*pos)++) {
                 int bit;
-
-                if ((evs[*pos].delta.tv_nsec < MIN_PULSE_TIME) |
-                    (evs[*pos].delta.tv_nsec > MAX_PULSE_TIME) |
-                    (evs[*pos].type != IR_PULSE))
-                        goto err;
-
-                if (++*pos >= len)
-                        goto err;
-                if (evs[*pos].type != IR_SPACE)
-                        goto err;
-
                 if ((evs[*pos].delta.tv_nsec > MIN_BIT1_TIME) &&
                     (evs[*pos].delta.tv_nsec < MAX_BIT1_TIME))
                         bit = 1;
@@ -107,6 +147,7 @@ static int __ir_nec_decode(struct input_dev *input_dev,
                 if (++count == 32)
                         break;
         }
+        *pos++;
 
         /*
          * Fixme: may need to accept Extended NEC protocol?
@@ -119,12 +160,15 @@ static int __ir_nec_decode(struct input_dev *input_dev,
 
         IR_dprintk(1, "NEC scancode 0x%04x\n", ircode);
         ir_keydown(input_dev, ircode);
-        ir_keyup(input_dev);
+        mod_timer(&ir->raw->timer_keyup,
+                  jiffies + msecs_to_jiffies(REPEAT_TIME));
 
-        return ircode;
+        return 1;
 err:
-        IR_dprintk(1, "NEC decoded failed at bit %d while decoding %luus time\n",
-                   count, (evs[*pos].delta.tv_nsec + 500) / 1000);
+        IR_dprintk(1, "NEC decoded failed at bit %d (%s) while decoding %luus time\n",
+                   count,
+                   (evs[*pos].type & IR_SPACE) ? "space" : "pulse",
+                   (evs[*pos].delta.tv_nsec + 500) / 1000);
 
         return -EINVAL;
 }
@@ -145,7 +189,7 @@ int ir_nec_decode(struct input_dev *input_dev,
         int rc = 0;
 
         while (pos < len) {
-                if (__ir_nec_decode(input_dev, evs, len, &pos) >= 0)
+                if (__ir_nec_decode(input_dev, evs, len, &pos) > 0)
                         rc++;
         }