svn commit: r364148 - head/sys/arm/allwinner

[Andriy Gapon]

Author: avg
Date: Wed Aug 12 09:56:21 2020
New Revision: 364148
URL: https://svnweb.freebsd.org/changeset/base/364148

Log:
  aw_cir: lower activation threshold to support NECx protocol
  
  In NECx the leading mark has length of 8T as opposed to 16T in NEC,
  where T is  562.5 us.  So, 4.5 ms.
  Our threshold was set to 128 * 42.7 us (derived from the sampling
  frequency of 3/128 MHz).  So, ~5.5 ms.
  
  The new threshold is set to AW_IR_L1_MIN.  I think that's a good enough
  lower bound for detecting the leading pulse.
  
  Also, calculations of active_delay (which is activation delay) are fixed.
  Previously they would be wrong if AW_IR_ACTIVE_T was anything but zero,
  because the value was already bit-shifted.
  
  Finally, I am not sure why the activation delay was divided by two when
  calculating the initial pulse length.  I have not found anything that
  would explain or justify it.  So, I removed that division.
  
  MFC after:	3 weeks

Modified:
  head/sys/arm/allwinner/aw_cir.c

Modified: head/sys/arm/allwinner/aw_cir.c
==============================================================================
--- head/sys/arm/allwinner/aw_cir.c	Wed Aug 12 09:52:39 2020	(r364147)
+++ head/sys/arm/allwinner/aw_cir.c	Wed Aug 12 09:56:21 2020	(r364148)
@@ -126,8 +126,10 @@ __FBSDID("$FreeBSD$");
 #define	AW_IR_DMAX			53
 
 /* Active Thresholds */
-#define	AW_IR_ACTIVE_T			((0 & 0xff) << 16)
-#define	AW_IR_ACTIVE_T_C		((1 & 0xff) << 23)
+#define	AW_IR_ACTIVE_T_VAL		AW_IR_L1_MIN
+#define	AW_IR_ACTIVE_T			(((AW_IR_ACTIVE_T_VAL - 1) & 0xff) << 16)
+#define	AW_IR_ACTIVE_T_C_VAL		0
+#define	AW_IR_ACTIVE_T_C		((AW_IR_ACTIVE_T_C_VAL & 0xff) << 23)
 
 /* Code masks */
 #define	CODE_MASK			0x00ff00ff
@@ -209,9 +211,9 @@ aw_ir_decode_packets(struct aw_ir_softc *sc)
 		device_printf(sc->dev, "sc->dcnt = %d\n", sc->dcnt);
 
 	/* Find Lead 1 (bit separator) */
-	active_delay = (AW_IR_ACTIVE_T + 1) * (AW_IR_ACTIVE_T_C != 0 ? 128 : 1);
-	len = 0;
-	len += (active_delay >> 1);
+	active_delay = AW_IR_ACTIVE_T_VAL *
+	    (AW_IR_ACTIVE_T_C_VAL != 0 ? 128 : 1);
+	len = active_delay;
 	if (bootverbose)
 		device_printf(sc->dev, "Initial len: %ld\n", len);
 	for (i = 0;  i < sc->dcnt; i++) {