Clean up power LED state machine on link

The power LED now has its own tick-based handler which knows how to
blink the LED and resend the desired LED state to work around the
flaky 1-wire connection.

Removes a bunch of LED state code from charge_state.c.

No user-visible impact.  Does not need to go into link branch.

BUG=chromium-os:18256
BRANCH=none
TEST=manual

1) Discharge battery to <97%
2) Plug in AC.  LED=yellow
3) 'ectool chargeforceidle 1' from root shell.  LED=blinking green/off.
4) 'ectool chargeforceidle 0' from root shell.  LED=yellow.
5) Wait for battery >= 97% (or 'battfake 98' from EC console).  LED=green.
6) Unplug battery.  LED=red (may take 10 sec).
7) Replug battery.  LED=green.

Change-Id: I999ee3e1abe269bb3f737bbc75e0b872316605ce
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/45469
Reviewed-by: Vic Yang <victoryang@chromium.org>

4 files changed, 91 insertions, 76 deletions

diff --git a/common/charge_state.c b/common/charge_state.c
index 5cbea09aa6..8c93595d15 100644
--- a/common/charge_state.c
+++ b/common/charge_state.c
@@ -15,7 +15,6 @@
 #include "gpio.h"
 #include "hooks.h"
 #include "host_command.h"
-#include "power_led.h"
 #include "printf.h"
 #include "smart_battery.h"
 #include "switch.h"
@@ -31,9 +30,6 @@
 /* Voltage debounce time */
 #define DEBOUNCE_TIME (10 * SECOND)
 
-/* Time period between setting power LED */
-#define SET_LED_PERIOD (10 * SECOND)
-
 /* Timeout after AP battery shutdown warning before we kill the AP */
 #define LOW_BATTERY_SHUTDOWN_TIMEOUT_US (30 * SECOND)
 
@@ -577,6 +573,16 @@ enum power_state charge_get_state(void)
 	return task_ctx.curr.state;
 }
 
+uint32_t charge_get_flags(void)
+{
+	uint32_t flags = 0;
+
+	if (state_machine_force_idle)
+		flags |= CHARGE_FLAG_FORCE_IDLE;
+
+	return flags;
+}
+
 int charge_get_percent(void)
 {
 	return task_ctx.curr.batt.state_of_charge;
@@ -603,18 +609,6 @@ static int exit_force_idle_mode(void)
 	return EC_SUCCESS;
 }
 
-static enum powerled_color force_idle_led_blink(void)
-{
-	static enum powerled_color last = POWERLED_GREEN;
-
-	if (last == POWERLED_GREEN)
-		last = POWERLED_OFF;
-	else
-		last = POWERLED_GREEN;
-
-	return last;
-}
-
 /**
  * Battery charging task
  */
@@ -625,9 +619,6 @@ void charge_state_machine_task(void)
 	int sleep_usec = POLL_PERIOD_SHORT, diff_usec, sleep_next;
 	enum power_state new_state;
 	uint8_t batt_flags;
-	enum powerled_color led_color = POWERLED_OFF;
-	int rv_setled = 0;
-	uint64_t last_setled_time = 0;
 
 	while (1) {
 		state_common(ctx);
@@ -724,10 +715,6 @@ void charge_state_machine_task(void)
 			*ctx->memmap_batt_flags = batt_flags;
 
 			/* Charge done */
-			led_color = POWERLED_GREEN;
-			rv_setled = powerled_set(POWERLED_GREEN);
-			last_setled_time = get_time().val;
-
 			sleep_usec = (new_state == PWR_STATE_IDLE ?
 				      POLL_PERIOD_LONG : POLL_PERIOD_CHARGE);
 			break;
@@ -745,36 +732,14 @@ void charge_state_machine_task(void)
 			*ctx->memmap_batt_flags = batt_flags;
 
 			/* Charging */
-			led_color = POWERLED_YELLOW;
-			rv_setled = powerled_set(POWERLED_YELLOW);
-			last_setled_time = get_time().val;
-
 			sleep_usec = POLL_PERIOD_CHARGE;
 			break;
 		case PWR_STATE_ERROR:
 			/* Error */
-			led_color = POWERLED_RED;
-			rv_setled = powerled_set(POWERLED_RED);
-			last_setled_time = get_time().val;
-
 			sleep_usec = POLL_PERIOD_CHARGE;
 			break;
 		case PWR_STATE_UNCHANGE:
 			/* Don't change sleep duration */
-			if (state_machine_force_idle)
-				powerled_set(force_idle_led_blink());
-			else if (rv_setled || get_time().val - last_setled_time
-					> SET_LED_PERIOD) {
-				/*
-				 * Power LED may go off if AC adapter is
-				 * partially removed, even though AC power is
-				 * still provided.  Update the power LED
-				 * periodically so it will come back on in this
-				 * case.
-				 */
-				rv_setled = powerled_set(led_color);
-				last_setled_time = get_time().val;
-			}
 			break;
 		default:
 			/* Other state; poll quickly and hope it goes away */
diff --git a/common/power_led.c b/common/power_led.c
index 1e4b89505b..25af303421 100644
--- a/common/power_led.c
+++ b/common/power_led.c
@@ -1,18 +1,28 @@
-/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* Power LED control for Chrome EC */
 
+#include "charge_state.h"
 #include "console.h"
+#include "hooks.h"
 #include "onewire.h"
-#include "power_led.h"
+#include "switch.h"
 #include "timer.h"
 #include "util.h"
 
 #define POWERLED_RETRIES 10
 
+enum powerled_color {
+	POWERLED_OFF = 0,
+	POWERLED_RED,
+	POWERLED_YELLOW,
+	POWERLED_GREEN,
+	POWERLED_COLOR_COUNT  /* Number of colors, not a color itself */
+};
+
 static const uint8_t led_masks[POWERLED_COLOR_COUNT] = {0xff, 0xfe, 0xfc, 0xfd};
 static const char * const color_names[POWERLED_COLOR_COUNT] = {
 	"off", "red", "yellow", "green"};
@@ -50,7 +60,7 @@ static int powerled_set_mask(int mask)
 	return EC_SUCCESS;
 }
 
-int powerled_set(enum powerled_color color)
+static int powerled_set(enum powerled_color color)
 {
 	int rv = EC_SUCCESS;
 	int i;
@@ -79,6 +89,64 @@ int powerled_set(enum powerled_color color)
 }
 
 /*****************************************************************************/
+/* Hooks */
+
+static void powerled_tick(void)
+{
+	static enum powerled_color current_color = POWERLED_COLOR_COUNT;
+	static int tick_count;
+	enum powerled_color new_color = POWERLED_OFF;
+
+	tick_count++;
+
+	if (!switch_get_ac_present()) {
+		/* AC isn't present, so the power LED on the AC plug is off */
+		current_color = POWERLED_OFF;
+		return;
+	}
+
+	/* Translate charge state to LED color */
+	switch (charge_get_state()) {
+	case PWR_STATE_IDLE:
+		if (charge_get_flags() & CHARGE_FLAG_FORCE_IDLE)
+			new_color = ((tick_count & 1) ?
+				     POWERLED_GREEN : POWERLED_OFF);
+		else
+			new_color = POWERLED_GREEN;
+		break;
+	case PWR_STATE_CHARGE:
+		new_color = POWERLED_YELLOW;
+		break;
+	case PWR_STATE_CHARGE_NEAR_FULL:
+		new_color = POWERLED_GREEN;
+		break;
+	case PWR_STATE_ERROR:
+		new_color = POWERLED_RED;
+		break;
+	default:
+		/* Other states don't change LED color */
+		break;
+	}
+
+	/*
+	 * The power adapter on link can partially unplug and lose its LED
+	 * state.  There's no way to detect this, so just assume it forgets its
+	 * state every 10 seconds.
+	 */
+	if (!(tick_count % 10))
+		current_color = POWERLED_COLOR_COUNT;
+
+	/* If current color is still correct, leave now */
+	if (new_color == current_color)
+		return;
+
+	/* Update LED */
+	if (!powerled_set(new_color))
+		current_color = new_color;
+}
+DECLARE_HOOK(HOOK_SECOND, powerled_tick, HOOK_PRIO_DEFAULT);
+
+/*****************************************************************************/
 /* Console commands */
 
 static int command_powerled(int argc, char **argv)
diff --git a/include/charge_state.h b/include/charge_state.h
index fcb68be89d..bf6404593e 100644
--- a/include/charge_state.h
+++ b/include/charge_state.h
@@ -62,6 +62,10 @@ enum power_state {
 	PWR_STATE_ERROR
 };
 
+/* Charge state flags */
+/* Forcing idle state */
+#define CHARGE_FLAG_FORCE_IDLE (1 << 0)
+
 /* Debugging constants, in the same order as enum power_state. This string
  * table was moved here to sync with enum above.
  */
@@ -128,6 +132,11 @@ enum power_state trickle_charge(struct power_state_context *ctx);
 enum power_state charge_get_state(void);
 
 /**
+ * Return current charge state flags (CHARGE_FLAG_*)
+ */
+uint32_t charge_get_flags(void);
+
+/**
  * Return current battery charge percentage.
  */
 int charge_get_percent(void);
diff --git a/include/power_led.h b/include/power_led.h
index 2fd7322095..20b3f7793f 100644
--- a/include/power_led.h
+++ b/include/power_led.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
@@ -10,33 +10,6 @@
 
 #include "common.h"
 
-/* Interface for LM4-based boards */
-
-enum powerled_color {
-	POWERLED_OFF = 0,
-	POWERLED_RED,
-	POWERLED_YELLOW,
-	POWERLED_GREEN,
-	POWERLED_COLOR_COUNT  /* Number of colors, not a color itself */
-};
-
-#ifdef CONFIG_POWER_LED
-
-/**
- * Set the power adapter LED
- *
- * @param color		Color to set LED
- *
- * @return EC_SUCCESS, or non-zero if error.
- */
-int powerled_set(enum powerled_color color);
-
-#else
-
-static inline int powerled_set(enum powerled_color color) { return 0; }
-
-#endif
-
 /* Interface for STM32-based boards */
 
 enum powerled_state {