Monitor video detachment with ADC watchdog

This eliminates a per-second hook and removes a duplicated ADC read per
second. Also, TSU6721 is now reset after every detachment. This way, we
don't suffer from TSU6721 dirty state (most commonly seen after OTG
dongle detached.)

BUG=chrome-os-partner:17928
TEST=1. Test plugging/unplugging video dongle.
     2. Test Toad cable mode switching.
     3. Test charging with 200K charger.
BRANCH=spring

Change-Id: Ic035b7332e07ca385d766c735ce39efd31e46034
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/49578
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 72 insertions, 41 deletions

diff --git a/common/extpower_usb.c b/common/extpower_usb.c
index 98200542e0..895406861f 100644
--- a/common/extpower_usb.c
+++ b/common/extpower_usb.c
@@ -86,7 +86,8 @@ static int nominal_pwm_duty;
 static int current_pwm_duty;
 static int user_pwm_duty = -1;
 
-static int pending_tsu6721_reset;
+static int pending_toad_redetect;
+static int pending_video_detach;
 
 static enum {
 	LIMIT_NORMAL,
@@ -96,6 +97,7 @@ static enum {
 static enum {
 	ADC_WATCH_NONE,
 	ADC_WATCH_TOAD,
+	ADC_WATCH_VIDEO,
 } current_watchdog = ADC_WATCH_NONE;
 
 struct {
@@ -331,6 +333,34 @@ static void adc_watch_toad(void)
 	current_watchdog = ADC_WATCH_TOAD;
 }
 
+static void adc_watch_video(void)
+{
+	int retry_count = 10;
+
+	/*
+	 * Let DP_SNS voltage settle so that we don't trigger watchdog
+	 * unintentionally.
+	 */
+	while (retry_count-- &&
+	       adc_read_channel(ADC_CH_USB_DP_SNS) > VIDEO_ID_THRESHOLD)
+		msleep(20);
+
+	/* DP_SNS kept high. Assuming dongle detached already. */
+	if (retry_count <= 0) {
+		pending_video_detach = 1;
+		return;
+	}
+
+	/*
+	 * Watch DP_SNS and interrupt if voltage goes above
+	 * VIDEO_ID_THRESHOLD
+	 */
+	adc_enable_watchdog(STM32_AIN(2), VIDEO_ID_THRESHOLD * 4096 / 3300, 0);
+	task_clear_pending_irq(STM32_IRQ_ADC_1);
+	task_enable_irq(STM32_IRQ_ADC_1);
+	current_watchdog = ADC_WATCH_VIDEO;
+}
+
 static int usb_has_power_input(int dev_type)
 {
 	if (dev_type & TSU6721_TYPE_JIG_UART_ON)
@@ -457,7 +487,6 @@ static void usb_log_dev_type(int dev_type)
 
 static void usb_device_change(int dev_type)
 {
-
 	if (current_dev_type == dev_type)
 		return;
 
@@ -483,6 +512,8 @@ static void usb_device_change(int dev_type)
 	if ((dev_type & TOAD_DEVICE_TYPE) &&
 	    (dev_type & TSU6721_TYPE_VBUS_DEBOUNCED))
 		adc_watch_toad();
+	else if (dev_type & TSU6721_TYPE_JIG_UART_ON)
+		adc_watch_video();
 
 	usb_log_dev_type(dev_type);
 
@@ -532,15 +563,33 @@ void extpower_charge_init(void)
 void extpower_charge_update(int force_update)
 {
 	int int_val = 0;
+	int want_reset = 0;
 
-	if (pending_tsu6721_reset) {
+	if (pending_video_detach || pending_toad_redetect) {
 		current_watchdog = ADC_WATCH_NONE;
 		adc_disable_watchdog();
+		want_reset = 1;
+	}
+
+	if (pending_video_detach) {
+		set_video_power(0);
+		gpio_set_level(GPIO_ID_MUX, 0);
+		msleep(DELAY_ID_MUX_MS);
+		tsu6721_enable_interrupts();
+	}
+
+	pending_video_detach = 0;
+	pending_toad_redetect = 0;
+
+	if (!want_reset) {
+		int_val = tsu6721_get_interrupts();
+		want_reset = (int_val & TSU6721_INT_DETACH);
+	}
+
+	if (want_reset) {
 		tsu6721_reset();
 		force_update = 1;
-		pending_tsu6721_reset = 0;
-	} else
-		int_val = tsu6721_get_interrupts();
+	}
 
 	if (int_val & TSU6721_INT_DETACH)
 		usb_device_change(TSU6721_TYPE_NONE);
@@ -583,11 +632,12 @@ void extpower_interrupt(enum gpio_signal signal)
 
 static void adc_watchdog_interrupt(void)
 {
-	if (current_watchdog == ADC_WATCH_TOAD) {
-		pending_tsu6721_reset = 1;
-		task_disable_irq(STM32_IRQ_ADC_1);
-		task_wake(TASK_ID_CHARGER);
-	}
+	if (current_watchdog == ADC_WATCH_TOAD)
+		pending_toad_redetect = 1;
+	else if (current_watchdog == ADC_WATCH_VIDEO)
+		pending_video_detach = 1;
+	task_disable_irq(STM32_IRQ_ADC_1);
+	task_wake(TASK_ID_CHARGER);
 }
 DECLARE_IRQ(STM32_IRQ_ADC_1, adc_watchdog_interrupt, 2);
 
@@ -603,7 +653,7 @@ static void usb_boost_pwr_off_hook(void)
 }
 DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, usb_boost_pwr_off_hook, HOOK_PRIO_DEFAULT);
 
-static void pwm_tweak(void)
+static void power_tweak(void)
 {
 	int vbus, current;
 
@@ -611,6 +661,15 @@ static void pwm_tweak(void)
 		return;
 
 	vbus = adc_read_channel(ADC_CH_USB_VBUS_SNS);
+
+	/* Check video power input change */
+	if (current_dev_type & TSU6721_TYPE_JIG_UART_ON) {
+		if (get_video_power() && vbus > 4000)
+			set_video_power(0);
+		else if (!get_video_power() && vbus <= 4000)
+			set_video_power(1);
+	}
+
 	if (battery_current(&current))
 		return;
 
@@ -637,35 +696,7 @@ static void pwm_tweak(void)
 		CPRINTF("[%T PWM duty down %d%%]\n", current_pwm_duty);
 	}
 }
-DECLARE_HOOK(HOOK_SECOND, pwm_tweak, HOOK_PRIO_DEFAULT);
-
-/*
- * TODO(victoryang): Get rid of polling loop when ADC watchdog is ready.
- *                   See crosbug.com/p/18171
- */
-static void usb_monitor_detach(void)
-{
-	int vbus;
-
-	if (!(current_dev_type & TSU6721_TYPE_JIG_UART_ON))
-		return;
-
-	if (adc_read_channel(ADC_CH_USB_DP_SNS) > VIDEO_ID_THRESHOLD) {
-		set_video_power(0);
-		gpio_set_level(GPIO_ID_MUX, 0);
-		msleep(DELAY_ID_MUX_MS);
-		tsu6721_enable_interrupts();
-		usb_device_change(TSU6721_TYPE_NONE);
-	}
-
-	/* Check if there is external power */
-	vbus = adc_read_channel(ADC_CH_USB_VBUS_SNS);
-	if (get_video_power() && vbus > 4000)
-		set_video_power(0);
-	else if (!get_video_power() && vbus <= 4000)
-		set_video_power(1);
-}
-DECLARE_HOOK(HOOK_SECOND, usb_monitor_detach, HOOK_PRIO_DEFAULT);
+DECLARE_HOOK(HOOK_SECOND, power_tweak, HOOK_PRIO_DEFAULT);
 
 /*****************************************************************************/
 /*