lightbar: bring the TAP sequence in gradually

With only four LED segments, it's confusing to indicate a power
percentage by dimming the top segment unless you can see the
indicator smoothly ramping up from all-off. This does that.
Kind of pretty, if I say so myself.

BUG=chrome-os-partner:29041
BRANCH=ToT, Samus
TEST=make buildall

Run "ectool lightbar demo on", then press the T key to invoke the
pattern and the arrow keys to fake the charge state.

Change-Id: Ib6a56aea56078b8c1fc9edddda469d7f41735ff7
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/223300
Reviewed-by: Alec Berg <alecaberg@chromium.org>

4 files changed, 20 insertions, 2 deletions

diff --git a/common/lightbar.c b/common/lightbar.c
index cd6595bb21..f8dce75c50 100644
--- a/common/lightbar.c
+++ b/common/lightbar.c
@@ -76,7 +76,8 @@ static const struct lightbar_params_v1 default_params = {
 	.s3_ramp_up = 2500,
 	.s3_ramp_down = 10000,
 	.tap_tick_delay = 5000,			/* oscillation step time */
-	.tap_display_time = 5 * SECOND,		/* total sequence time */
+	.tap_gate_delay = 200 * MSEC,		/* segment gating delay */
+	.tap_display_time = 3 * SECOND,		/* total sequence time */
 
 	.tap_pct_red = 10,			/* below this is red */
 	.tap_pct_green = 97,			/* above this is green */
@@ -804,8 +805,10 @@ static uint32_t sequence_TAP_inner(void)
 {
 	enum { RED, YELLOW, GREEN } base_color;
 	timestamp_t start, now;
+	uint32_t elapsed_time = 0;
 	int i, ci, max_led;
 	int f_min, f_delta, f_osc, f_power, f_mult;
+	int gi, gr, gate[NUM_LEDS] = {0, 0, 0, 0};
 	uint8_t w = 0;
 
 	f_min = st.p.tap_seg_min_on * FP_SCALE / 100;
@@ -826,6 +829,14 @@ static uint32_t sequence_TAP_inner(void)
 		ci = st.p.tap_idx[base_color];
 		max_led = st.battery_percent / CUT;
 
+		/* Enable the segments gradually */
+		gi = elapsed_time / st.p.tap_gate_delay;
+		gr = elapsed_time % st.p.tap_gate_delay;
+		if (gi < NUM_LEDS)
+			gate[gi] = FP_SCALE * gr / st.p.tap_gate_delay;
+		if (gi && gi <= NUM_LEDS)
+			gate[gi - 1] = FP_SCALE;
+
 		for (i = 0; i < NUM_LEDS; i++) {
 
 			if (max_led > i) {
@@ -849,6 +860,8 @@ static uint32_t sequence_TAP_inner(void)
 				f_mult = f_min + f_power * f_delta / FP_SCALE;
 			}
 
+			f_mult = f_mult * gate[i] / FP_SCALE;
+
 			/* Pulse when charging */
 			if (st.battery_is_charging) {
 				int scale = (FP_SCALE -
@@ -865,7 +878,8 @@ static uint32_t sequence_TAP_inner(void)
 
 		/* Return after some time has elapsed */
 		now = get_time();
-		if (now.le.lo - start.le.lo > st.p.tap_display_time)
+		elapsed_time = now.le.lo - start.le.lo;
+		if (elapsed_time > st.p.tap_display_time)
 			break;
 	}
 	return 0;
diff --git a/extra/lightbar/main.c b/extra/lightbar/main.c
index a0da1a28ba..897a58d518 100644
--- a/extra/lightbar/main.c
+++ b/extra/lightbar/main.c
@@ -209,6 +209,7 @@ int lb_read_params_from_file(const char *filename,
 	READ(1); p->s3_ramp_up = val[0];
 	READ(1); p->s3_ramp_down = val[0];
 	READ(1); p->tap_tick_delay = val[0];
+	READ(1); p->tap_gate_delay = val[0];
 	READ(1); p->tap_display_time = val[0];
 
 	READ(1); p->tap_pct_red = val[0];
diff --git a/include/ec_commands.h b/include/ec_commands.h
index 5987c46568..14abf48c09 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -1018,6 +1018,7 @@ struct lightbar_params_v1 {
 	int32_t s3_ramp_up;
 	int32_t s3_ramp_down;
 	int32_t tap_tick_delay;
+	int32_t tap_gate_delay;
 	int32_t tap_display_time;
 
 	/* Tap-for-battery params */
diff --git a/util/ectool.c b/util/ectool.c
index 7410c6f6db..b166e11f64 100644
--- a/util/ectool.c
+++ b/util/ectool.c
@@ -1951,6 +1951,7 @@ static int lb_read_params_v1_from_file(const char *filename,
 	READ(1); p->s3_ramp_up = val[0];
 	READ(1); p->s3_ramp_down = val[0];
 	READ(1); p->tap_tick_delay = val[0];
+	READ(1); p->tap_gate_delay = val[0];
 	READ(1); p->tap_display_time = val[0];
 
 	READ(1); p->tap_pct_red = val[0];
@@ -2049,6 +2050,7 @@ static void lb_show_params_v1(const struct lightbar_params_v1 *p)
 	printf("%d\t\t# .s3_ramp_up\n", p->s3_ramp_up);
 	printf("%d\t\t# .s3_ramp_down\n", p->s3_ramp_down);
 	printf("%d\t\t# .tap_tick_delay\n", p->tap_tick_delay);
+	printf("%d\t\t# .tap_gate_delay\n", p->tap_gate_delay);
 	printf("%d\t\t# .tap_display_time\n", p->tap_display_time);
 	printf("%d\t\t# .tap_pct_red\n", p->tap_pct_red);
 	printf("%d\t\t# .tap_pct_green\n", p->tap_pct_green);