Fizz: Pulse LED

This change makes the power LEDs pulse using PWM.
S0: solid green.
S3: pulsing amber (= mix of green and red)
S5: off

BUG=b:64975836
BRANCH=none
TEST=Verify LED behavior described above on Proto3

Change-Id: I696cf8279dd762236b7b7f000a316820d58916bf
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/669773
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

5 files changed, 101 insertions, 31 deletions

diff --git a/board/fizz/board.c b/board/fizz/board.c
index 0fd6e6dd76..b57a0fa58f 100644
--- a/board/fizz/board.c
+++ b/board/fizz/board.c
@@ -23,6 +23,7 @@
 #include "driver/tcpm/ps8xxx.h"
 #include "driver/tcpm/tcpci.h"
 #include "driver/tcpm/tcpm.h"
+#include "espi.h"
 #include "extpower.h"
 #include "gpio.h"
 #include "hooks.h"
@@ -32,6 +33,8 @@
 #include "pi3usb9281.h"
 #include "power.h"
 #include "power_button.h"
+#include "pwm.h"
+#include "pwm_chip.h"
 #include "spi.h"
 #include "switch.h"
 #include "system.h"
@@ -44,7 +47,6 @@
 #include "usb_pd.h"
 #include "usb_pd_tcpm.h"
 #include "util.h"
-#include "espi.h"
 
 #define CPRINTS(format, args...) cprints(CC_USBCHARGE, format, ## args)
 #define CPRINTF(format, args...) cprintf(CC_USBCHARGE, format, ## args)
@@ -461,3 +463,9 @@ int board_has_working_reset_flags(void)
 	/* All other board versions should have working reset flags */
 	return 1;
 }
+
+const struct pwm_t pwm_channels[] = {
+	[PWM_CH_LED_RED]   = { 3, PWM_CONFIG_DSLEEP, 100 },
+	[PWM_CH_LED_GREEN] = { 5, PWM_CONFIG_DSLEEP, 100 },
+};
+BUILD_ASSERT(ARRAY_SIZE(pwm_channels) == PWM_CH_COUNT);
diff --git a/board/fizz/board.h b/board/fizz/board.h
index 723df09813..1259dea23d 100644
--- a/board/fizz/board.h
+++ b/board/fizz/board.h
@@ -31,6 +31,7 @@
 #define CONFIG_I2C_MASTER
 #undef  CONFIG_LID_SWITCH
 #define CONFIG_POWER_BUTTON_IGNORE_LID
+#define CONFIG_PWM
 #define CONFIG_LTO
 #define CONFIG_CHIP_PANIC_BACKUP
 #define CONFIG_SPI_FLASH_REGS
@@ -206,6 +207,12 @@ enum button {
 	BUTTON_COUNT
 };
 
+enum pwm_channel {
+	PWM_CH_LED_RED,
+	PWM_CH_LED_GREEN,
+	PWM_CH_COUNT
+};
+
 /* TODO(crosbug.com/p/61098): Verify the numbers below. */
 /*
  * delay to turn on the power supply max is ~16ms.
diff --git a/board/fizz/ec.tasklist b/board/fizz/ec.tasklist
index b60ae990a7..58d509ebbd 100644
--- a/board/fizz/ec.tasklist
+++ b/board/fizz/ec.tasklist
@@ -22,6 +22,7 @@
 
 #define CONFIG_TASK_LIST \
 	TASK_ALWAYS(HOOKS, hook_task, NULL, 2048) \
+	TASK_ALWAYS(LED, led_task, NULL, TASK_STACK_SIZE) \
 	/* Larger stack for RW verification (i.e. sha256, rsa) */ \
 	TASK_NOTEST(CHIPSET, chipset_task, NULL, TASK_STACK_SIZE) \
 	TASK_NOTEST(PDCMD, pd_command_task, NULL, TASK_STACK_SIZE) \
diff --git a/board/fizz/gpio.inc b/board/fizz/gpio.inc
index 4640e3c4da..da1fbcab25 100644
--- a/board/fizz/gpio.inc
+++ b/board/fizz/gpio.inc
@@ -44,8 +44,6 @@ GPIO(PMIC_INT_L,		PIN(6, 0), GPIO_INPUT)				/* PMIC interrupt */
 
 /* Fizz specific pins */
 GPIO(LAN_PWR_EN,		PIN(8, 3), GPIO_OUT_HIGH)			/* Ethernet power enabled */
-GPIO(PWR_RED_LED,		PIN(8, 0), GPIO_OUT_HIGH)			/* Power Red LED */
-GPIO(PWR_GRN_LED,		PIN(B, 7), GPIO_OUT_HIGH)			/* Power Green LED */
 
 /* TODO(crosbug.com/p/61098): Make use of these GPIOs */
 GPIO(PP3300_USB_PD,		PIN(6, 7), GPIO_OUTPUT)
@@ -104,3 +102,6 @@ ALTERNATE(PIN_MASK(9, 0x06), 1, MODULE_I2C, 0)		/* GPIO91-92 */		/* EC_I2C2_PMIC
 ALTERNATE(PIN_MASK(B, 0x30), 1, MODULE_I2C, 0)		/* GPIOB4-B5 */		/* EC_I2C0_0_USBC_3V3_SDA/SCL */
 ALTERNATE(PIN_MASK(B, 0x0C), 1, MODULE_I2C, 0)		/* GPOPB2-B3 */		/* EC_I2C0_1_3V3_SDA/SCL */
 ALTERNATE(PIN_MASK(D, 0x03), 1, MODULE_I2C, 0)		/* GPIOD0-D1 */		/* EC_I2C3_SENSOR_1V8_SDA/SCL */
+/* Alternate functions for LED PWM */
+ALTERNATE(PIN_MASK(8, 0x01), 1, MODULE_PWM, 0)		/* GPIO80 PWM3 Red*/
+ALTERNATE(PIN_MASK(B, 0x80), 1, MODULE_PWM, 0)		/* GPOB7 PWM5 Green*/
diff --git a/board/fizz/led.c b/board/fizz/led.c
index e6f336968a..0227f8498f 100644
--- a/board/fizz/led.c
+++ b/board/fizz/led.c
@@ -11,6 +11,8 @@
 #include "gpio.h"
 #include "hooks.h"
 #include "led_common.h"
+#include "pwm.h"
+#include "timer.h"
 #include "util.h"
 
 static int led_debug;
@@ -25,11 +27,14 @@ enum led_color {
 	LED_COLOR_COUNT
 };
 
-static int led_set_color_power(enum led_color color)
+static int set_color_power(enum led_color color, int duty)
 {
 	int green = 0;
 	int red = 0;
 
+	if (duty < 0 || 100 < duty)
+		return EC_ERROR_UNKNOWN;
+
 	switch (color) {
 	case LED_OFF:
 		break;
@@ -47,49 +52,93 @@ static int led_set_color_power(enum led_color color)
 		return EC_ERROR_UNKNOWN;
 	}
 
-	gpio_set_level(GPIO_PWR_GRN_LED, green);
-	gpio_set_level(GPIO_PWR_RED_LED, red);
+	if (red)
+		pwm_set_duty(PWM_CH_LED_RED, duty);
+	else
+		pwm_set_duty(PWM_CH_LED_RED, 0);
+
+	if (green)
+		pwm_set_duty(PWM_CH_LED_GREEN, duty);
+	else
+		pwm_set_duty(PWM_CH_LED_GREEN, 0);
 
 	return EC_SUCCESS;
 }
 
-static int led_set_color(enum ec_led_id id, enum led_color color)
+static int set_color(enum ec_led_id id, enum led_color color, int duty)
 {
 	switch (id) {
 	case EC_LED_ID_POWER_LED:
-		return led_set_color_power(color);
+		return set_color_power(color, duty);
 	default:
 		return EC_ERROR_UNKNOWN;
 	}
 }
 
+/* led task increments brightness by <duty_inc> every <task_frequency_us> to go
+ * from 0% to 100% in <LED_PULSE_US>. Then it decreases brightness likewise in
+ * <LED_PULSE_US>. So, total time for one cycle is <LED_PULSE_US> x 2. */
+#define LED_PULSE_US	(2 * SECOND)
+static uint32_t task_frequency_us;
+static int duty_inc;
+
+static void set_task_frequency(uint32_t usec)
+{
+	task_frequency_us = usec;
+	duty_inc = 100 / (LED_PULSE_US / task_frequency_us);
+}
+
 static void led_set_power(void)
 {
-	static uint8_t suspend_ticks;
+	static int duty = 0;
 
 	if (chipset_in_state(CHIPSET_STATE_ON))
-		led_set_color(EC_LED_ID_POWER_LED, LED_GREEN);
+		set_color(EC_LED_ID_POWER_LED, LED_GREEN, 100);
 	else if (chipset_in_state(
 			CHIPSET_STATE_SUSPEND | CHIPSET_STATE_STANDBY))
-		/* Blink once every four seconds. */
-		led_set_color(EC_LED_ID_POWER_LED,
-			      (suspend_ticks % 4) ? LED_OFF : LED_GREEN);
+		set_color(EC_LED_ID_POWER_LED, LED_AMBER, duty);
 	else
-		led_set_color(EC_LED_ID_POWER_LED, LED_OFF);
+		set_color(EC_LED_ID_POWER_LED, LED_OFF, 0);
 
-	suspend_ticks++;
+	if (duty + duty_inc > 100)
+		duty_inc = duty_inc * -1;
+	else if (duty + duty_inc < 0)
+		duty_inc = duty_inc * -1;
+	duty += duty_inc;
 }
 
-/**
- * Called by hook task every 250 ms
- */
-static void led_tick(void)
+void led_task(void *u)
+{
+	uint32_t interval;
+	uint32_t start;
+
+	while (1) {
+		start = get_time().le.lo;
+		if (!led_debug)
+			led_set_power();
+		interval = get_time().le.lo - start;
+		if (task_frequency_us > interval)
+			usleep(task_frequency_us - interval);
+	}
+}
+
+static void led_init(void)
 {
-	if (led_debug)
-		return;
-	led_set_power();
+	/*
+	 * Enable PWMs and set to 0% duty cycle.  If they're disabled,
+	 * seems to ground the pins instead of letting them float.
+	 */
+	pwm_enable(PWM_CH_LED_RED, 1);
+	pwm_enable(PWM_CH_LED_GREEN, 1);
+
+	/* 40 msec for nice and smooth transition */
+	set_task_frequency(40 * MSEC);
+
+	/* From users' perspective, system-on means AP-on */
+	set_color(EC_LED_ID_POWER_LED, LED_OFF, 0);
 }
-DECLARE_HOOK(HOOK_SECOND, led_tick, HOOK_PRIO_DEFAULT);
+/* After pwm_pin_init() */
+DECLARE_HOOK(HOOK_INIT, led_init, HOOK_PRIO_DEFAULT);
 
 static int command_led(int argc, char **argv)
 {
@@ -102,19 +151,23 @@ static int command_led(int argc, char **argv)
 		led_debug ^= 1;
 		ccprintf("led_debug %s\n", led_debug ? "on" : "off");
 	} else if (!strcasecmp(argv[1], "off")) {
-		led_set_color(id, LED_OFF);
+		set_color(id, LED_OFF, 0);
 	} else if (!strcasecmp(argv[1], "red")) {
-		led_set_color(id, LED_RED);
+		set_color(id, LED_RED, 100);
 	} else if (!strcasecmp(argv[1], "green")) {
-		led_set_color(id, LED_GREEN);
+		set_color(id, LED_GREEN, 100);
 	} else if (!strcasecmp(argv[1], "amber")) {
-		led_set_color(id, LED_AMBER);
+		set_color(id, LED_AMBER, 100);
 	} else {
-		/* maybe handle charger_discharge_on_ac() too? */
-		return EC_ERROR_PARAM1;
+		char *e;
+		uint32_t msec = strtoi(argv[1], &e, 0);
+		if (*e)
+			return EC_ERROR_PARAM1;
+		set_task_frequency(msec * MSEC);
 	}
 	return EC_SUCCESS;
 }
 DECLARE_CONSOLE_COMMAND(led, command_led,
-			"[debug|red|green|amber|off]",
-			"Turn on/off LED");
+			"[debug|red|green|amber|off|num]",
+			"Turn on/off LED. If a number is given, it changes led"
+			"task frequency (msec).");