rambi: Leave 5V rail on in S3 if USB ports are powered

Previously, the 5V rail was disabled unconditionally in the S0->S3
transition.  Now, the rail is left powered if one or both of the USB
ports are powered.

BUG=chrome-os-partner:25178
BRANCH=rambi
TEST=Modify the OS to leave USB ports powered in S3.  Then suspend.  On
     the EC console, 'gpioget pp5000_en' should be 1.

Change-Id: I3c73f3fe228e940317c0da7330f117c7ab0a6d0c
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/183548
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

5 files changed, 43 insertions, 0 deletions

diff --git a/board/rambi/board.h b/board/rambi/board.h
index 62c0784ffe..bebe44e570 100644
--- a/board/rambi/board.h
+++ b/board/rambi/board.h
@@ -36,6 +36,7 @@
 #define CONFIG_SCI_GPIO GPIO_PCH_SCI_L
 #define CONFIG_TEMP_SENSOR
 #define CONFIG_TEMP_SENSOR_TMP432
+#define CONFIG_USB_PORT_POWER_IN_S3
 #define CONFIG_USB_PORT_POWER_SMART
 #define CONFIG_USB_PORT_POWER_SMART_SIMPLE
 #define CONFIG_VBOOT_HASH
diff --git a/common/usb_port_power_smart.c b/common/usb_port_power_smart.c
index 9a47d78326..89f72c7339 100644
--- a/common/usb_port_power_smart.c
+++ b/common/usb_port_power_smart.c
@@ -85,6 +85,19 @@ static void usb_charge_all_ports_off(void)
 	usb_charge_set_mode(1, USB_CHARGE_MODE_DISABLED);
 }
 
+int usb_charge_ports_enabled(void)
+{
+	int mask = 0;
+
+	if (gpio_get_level(GPIO_USB1_ENABLE))
+		mask |= (1 << 0);
+
+	if (gpio_get_level(GPIO_USB2_ENABLE))
+		mask |= (1 << 1);
+
+	return mask;
+}
+
 int usb_charge_set_mode(int port_id, enum usb_charge_mode mode)
 {
 	CPRINTF("[%T USB charge p%d m%d]\n", port_id, mode);
diff --git a/include/config.h b/include/config.h
index abf183151c..58f68e2b33 100644
--- a/include/config.h
+++ b/include/config.h
@@ -728,6 +728,12 @@
 #undef CONFIG_USB_PORT_POWER_DUMB
 
 /*
+ * Support supplying USB power in S3, if the host leaves the port enabled when
+ * entering S3.
+ */
+#undef CONFIG_USB_PORT_POWER_IN_S3
+
+/*
  * Support smart power control to the device's USB ports, using
  * dedicated power control chips.  This potentially enables automatic
  * negotiation of supplying more power to peripherals.
diff --git a/include/usb_charge.h b/include/usb_charge.h
index 66e6611985..e67aba482e 100644
--- a/include/usb_charge.h
+++ b/include/usb_charge.h
@@ -34,4 +34,12 @@ enum usb_charge_mode {
  */
 int usb_charge_set_mode(int usb_port_id, enum usb_charge_mode mode);
 
+/**
+ * Return a bitmask of which USB ports are enabled.
+ *
+ * If bit (1 << i) is set, port <i> is enabled.  If it is clear, port <i> is
+ * in USB_CHARGE_MODE_DISABLED.
+ */
+int usb_charge_ports_enabled(void);
+
 #endif  /* __CROS_EC_USB_CHARGE_H */
diff --git a/power/baytrail.c b/power/baytrail.c
index e938f9298e..8615964705 100644
--- a/power/baytrail.c
+++ b/power/baytrail.c
@@ -16,6 +16,7 @@
 #include "power.h"
 #include "system.h"
 #include "timer.h"
+#include "usb_charge.h"
 #include "util.h"
 #include "wireless.h"
 
@@ -315,13 +316,27 @@ enum power_state power_handle_state(enum power_state state)
 
 		/* Turn off power rails */
 		gpio_set_level(GPIO_PP3300_DX_EN, 0);
+
+#ifdef CONFIG_USB_PORT_POWER_IN_S3
+		/*
+		 * Disable the 5V rail if all USB ports are disabled.  Else
+		 * leave 5V enabled so the ports will continue to work in S3.
+		 */
+		if (!usb_charge_ports_enabled())
+			gpio_set_level(GPIO_PP5000_EN, 0);
+#else
 		gpio_set_level(GPIO_PP5000_EN, 0);
+#endif
+
 		return POWER_S3;
 
 	case POWER_S3S5:
 		/* Call hooks before we remove power rails */
 		hook_notify(HOOK_CHIPSET_SHUTDOWN);
 
+		/* Turn off 5V rail (if it wasn't turned off in S3) */
+		gpio_set_level(GPIO_PP5000_EN, 0);
+
 		/* Disable wireless */
 		wireless_enable(0);