Demo: Add walking one/walking zero pattern

src/hardware/demo/api.c

@@ -40,6 +40,8 @@ static const char *logic_pattern_str[] = {
 	"sigrok",
 	"random",
 	"incremental",
+	"walking one",
+	"walking zero",
 	"all-low",
 	"all-high",
 	"squid",

src/hardware/demo/protocol.c

@@ -279,6 +279,35 @@ static void logic_generator(struct sr_dev_inst *sdi, uint64_t size)
 			devc->step++;
 		}
 		break;
+	case PATTERN_WALKING_ONE:
+		/* j contains the value of the highest bit */
+	        j = 1 << (devc->num_logic_channels - 1);
+		for (i = 0; i < size; i++) {
+			devc->logic_data[i] = devc->step;
+			if (devc->step == 0)
+				devc->step = 1;
+			else
+				if (devc->step == j)
+					devc->step = 0;
+				else
+					devc->step <<= 1;
+		}
+		break;
+	case PATTERN_WALKING_ZERO:
+		/* Same as walking one, only with inverted output */
+		/* j contains the value of the highest bit */
+	        j = 1 << (devc->num_logic_channels - 1);
+		for (i = 0; i < size; i++) {
+			devc->logic_data[i] = ~devc->step;
+			if (devc->step == 0)
+				devc->step = 1;
+			else
+				if (devc->step == j)
+					devc->step = 0;
+				else
+					devc->step <<= 1;
+		}
+		break;
 	case PATTERN_ALL_LOW:
 	case PATTERN_ALL_HIGH:
 		/* These were set when the pattern mode was selected. */

src/hardware/demo/protocol.h

@@ -75,6 +75,16 @@ enum {
 	 */
 	PATTERN_INC,
 
+	/**
+	 * Single bit "walking" across all logic channels by being
+	 * shifted across data lines, restarting after the last line
+	 * was used. An all-zero (all-one) state is inserted to prevent
+	 * repetitive patterns (e.g. with 8 data lines, every 8th state
+	 * would show the same line state)
+	 */
+	PATTERN_WALKING_ONE,
+	PATTERN_WALKING_ZERO,
+
 	/** All channels have a low logic state. */
 	PATTERN_ALL_LOW,