gru: Add battery status LED control

Implement the standard LED control scheme for gru, using a single PWM to
set the battery status LED color rather than the traditional GPIOs.

BUG=chrome-os-partner:54379
BRANCH=None
TEST=Manual on gru. Verify LED is green when charging w/ nearly full
battery, off when discharging w/ nearly full battery, amber when
charging otherwise.
Also verify LED control host commands work as expected:
ectool led battery green=1  // green
ectool led battery amber=1  // amber
ectool led battery red=1    // red
ectool led battery red=0    // off

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I184e72c552e6d2196aef2724af9292806e0ea8c0
Reviewed-on: https://chromium-review.googlesource.com/352520
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: David Schneider <dnschneid@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>

3 files changed, 132 insertions, 3 deletions

diff --git a/board/kevin/board.h b/board/kevin/board.h
index 9b51328b2d..4e456260a4 100644
--- a/board/kevin/board.h
+++ b/board/kevin/board.h
@@ -14,12 +14,10 @@
 #define CONFIG_HOSTCMD_SPS
 #define CONFIG_I2C
 #define CONFIG_I2C_MASTER
+#define CONFIG_LED_COMMON
 #define CONFIG_POWER_COMMON
 #define CONFIG_PWM
 #define CONFIG_PWM_DISPLIGHT
-#ifdef BOARD_KEVIN
-#define CONFIG_LED_COMMON
-#endif
 #define CONFIG_SPI
 #define CONFIG_SPI_MASTER
 
diff --git a/board/kevin/build.mk b/board/kevin/build.mk
index e441c412f9..cf5289d541 100644
--- a/board/kevin/build.mk
+++ b/board/kevin/build.mk
@@ -11,4 +11,5 @@ CHIP:=npcx
 CHIP_VARIANT:=npcx5m5g
 
 board-y=battery.o board.o usb_pd_policy.o
+board-$(BOARD_GRU)+=led_gru.o
 board-$(BOARD_KEVIN)+=led_kevin.o
diff --git a/board/kevin/led_gru.c b/board/kevin/led_gru.c
new file mode 100644
index 0000000000..cbe59a2ad8
--- /dev/null
+++ b/board/kevin/led_gru.c
@@ -0,0 +1,130 @@
+/* Copyright 2016 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.
+ *
+ * gru battery LED control - derived from standard policy with PWM
+ * color control rather than GPIO.
+ */
+
+#include "battery.h"
+#include "charge_state.h"
+#include "chipset.h"
+#include "hooks.h"
+#include "led_common.h"
+#include "lid_switch.h"
+#include "pwm.h"
+#include "util.h"
+
+#define GRU_BAT_LED_PWM PWM_CH_LED_RED
+
+const enum ec_led_id supported_led_ids[] = { EC_LED_ID_BATTERY_LED };
+
+const int supported_led_ids_count = ARRAY_SIZE(supported_led_ids);
+
+enum led_color {
+	LED_OFF = 0,
+	LED_RED,
+	LED_AMBER,
+	LED_GREEN,
+	LED_COLOR_COUNT  /* Number of colors, not a color itself */
+};
+
+/* One LED active at a time. PWM low period determines which LED is active. */
+static const int led_color_to_pwm_duty[LED_COLOR_COUNT] = {
+	[LED_OFF] =   100,
+	[LED_RED] =   0,
+	[LED_AMBER] = 80,
+	[LED_GREEN] = 85,
+};
+
+static int bat_led_set_color(enum led_color color)
+{
+	pwm_set_duty(GRU_BAT_LED_PWM, led_color_to_pwm_duty[color]);
+	return EC_SUCCESS;
+}
+
+void led_get_brightness_range(enum ec_led_id led_id, uint8_t *brightness_range)
+{
+	switch (led_id) {
+	case EC_LED_ID_BATTERY_LED:
+		brightness_range[EC_LED_COLOR_RED] = 1;
+		brightness_range[EC_LED_COLOR_AMBER] = 1;
+		brightness_range[EC_LED_COLOR_GREEN] = 1;
+		break;
+	default:
+		/* ignore */
+		break;
+	}
+}
+
+int led_set_brightness(enum ec_led_id led_id, const uint8_t *brightness)
+{
+	switch (led_id) {
+	case EC_LED_ID_BATTERY_LED:
+		if (brightness[EC_LED_COLOR_RED] != 0)
+			bat_led_set_color(LED_RED);
+		else if (brightness[EC_LED_COLOR_AMBER] != 0)
+			bat_led_set_color(LED_AMBER);
+		else if (brightness[EC_LED_COLOR_GREEN] != 0)
+			bat_led_set_color(LED_GREEN);
+		else
+			bat_led_set_color(LED_OFF);
+		break;
+	default:
+		return EC_ERROR_UNKNOWN;
+	}
+	return EC_SUCCESS;
+}
+
+static void gru_led_set_battery(void)
+{
+	static int battery_second;
+	uint32_t chflags = charge_get_flags();
+
+	battery_second++;
+
+	/*
+	 * BAT LED behavior: Follow chromeos specification.
+	 * Green/Amber for CHARGE_FLAG_FORCE_IDLE
+	 */
+	switch (charge_get_state()) {
+	case PWR_STATE_CHARGE:
+		bat_led_set_color(LED_AMBER);
+		break;
+	case PWR_STATE_DISCHARGE:
+		if (charge_get_percent() < 3)
+			bat_led_set_color((battery_second & 1)
+					? LED_OFF : LED_AMBER);
+		else if (charge_get_percent() < 10)
+			bat_led_set_color((battery_second & 3)
+					? LED_OFF : LED_AMBER);
+		else
+			bat_led_set_color(LED_OFF);
+		break;
+	case PWR_STATE_ERROR:
+		bat_led_set_color((battery_second & 1) ? LED_OFF : LED_RED);
+		break;
+	case PWR_STATE_CHARGE_NEAR_FULL:
+		bat_led_set_color(LED_GREEN);
+		break;
+	case PWR_STATE_IDLE: /* External power connected in IDLE. */
+		if (chflags & CHARGE_FLAG_FORCE_IDLE)
+			bat_led_set_color(
+				(battery_second & 0x2) ? LED_GREEN : LED_AMBER);
+		else
+			bat_led_set_color(LED_GREEN);
+		break;
+	default:
+		/* Other states don't alter LED behavior */
+		break;
+	}
+}
+
+/* Called by hook task every 1 sec */
+static void led_second(void)
+{
+	if (led_auto_control_is_enabled(EC_LED_ID_BATTERY_LED))
+		gru_led_set_battery();
+}
+DECLARE_HOOK(HOOK_SECOND, led_second, HOOK_PRIO_DEFAULT);
+