meowth: Only power base when AP is on.

Previously, the base power was enabled when the base was detected by the
lid.  However, we should only power the base when the AP is on since it
just wastes power otherwise.  This commit adds a pair of chipset hooks
to kick the state machine on startup and disable it on shutdown.

BUG=None
BRANCH=None
TEST=Flash meowth, attach base with AP off, verify that base power is
not enabled.
TEST=Remove base and attach base, verify that base power is disabled
when removed and enabled when attached.
TEST=Shut AP down, verify that base power is disabled.
TEST=Remove base and attach base, verify that base power remains
disabled.
TEST=Power on AP with base detached, verify that base power remains off.

Change-Id: I4379789987dbe91c72d699c4d184b5c5cc812e5f
Signed-off-by: Aseda Aboagye <aaboagye@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1020525
Commit-Ready: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>

1 files changed, 46 insertions, 16 deletions

diff --git a/board/zoombini/base_detect.c b/board/zoombini/base_detect.c
index 3d6f0a8015..86df4a2c8b 100644
--- a/board/zoombini/base_detect.c
+++ b/board/zoombini/base_detect.c
@@ -17,6 +17,7 @@
  */
 
 #include "adc.h"
+#include "chipset.h"
 #include "common.h"
 #include "console.h"
 #include "gpio.h"
@@ -57,13 +58,23 @@ enum base_detect_state {
 static int debug;
 static enum base_detect_state state;
 
-static void base_detect_changed(void)
+static void base_power_enable(int enable)
 {
-	switch (state) {
-	case BASE_DETACHED:
-		/* Indicate that we are in tablet mode. */
-		tablet_set_mode(1);
+	/* Nothing to do if the state is the same. */
+	if (gpio_get_level(GPIO_BASE_PWR_EN) == enable)
+		return;
 
+	if (enable) {
+		/* Apply power to the base only if the AP is on or sleeping. */
+		if (chipset_in_state(CHIPSET_STATE_ON |
+				     CHIPSET_STATE_ANY_SUSPEND)) {
+			gpio_set_level(GPIO_BASE_PWR_EN, 1);
+			/* Allow time for the fault line to rise. */
+			msleep(1);
+			/* Monitor for base power faults. */
+			gpio_enable_interrupt(GPIO_BASE_PWR_FLT_L);
+		}
+	} else {
 		/*
 		 * Disable power fault interrupt.  It will read low when base
 		 * power is removed.
@@ -71,6 +82,18 @@ static void base_detect_changed(void)
 		gpio_disable_interrupt(GPIO_BASE_PWR_FLT_L);
 		/* Now, remove power to the base. */
 		gpio_set_level(GPIO_BASE_PWR_EN, 0);
+	}
+
+	CPRINTS("BP: %d", enable);
+}
+
+static void base_detect_changed(void)
+{
+	switch (state) {
+	case BASE_DETACHED:
+		/* Indicate that we are in tablet mode. */
+		tablet_set_mode(1);
+		base_power_enable(0);
 		break;
 
 	case BASE_ATTACHED:
@@ -79,13 +102,7 @@ static void base_detect_changed(void)
 		 * now, but we may have to revisit this.
 		 */
 		tablet_set_mode(0);
-
-		/* Apply power to the base. */
-		gpio_set_level(GPIO_BASE_PWR_EN, 1);
-		/* Allow time for the fault line to rise. */
-		msleep(1);
-		/* Monitor for base power faults. */
-		gpio_enable_interrupt(GPIO_BASE_PWR_FLT_L);
+		base_power_enable(1);
 		break;
 
 	default:
@@ -188,11 +205,24 @@ static void base_detect_deferred(void)
 		break;
 	};
 
-	/* Check again in the appropriate time. */
-	hook_call_deferred(&base_detect_deferred_data, timeout);
+	/* Check again in the appropriate time only if the AP is on. */
+	if (chipset_in_state(CHIPSET_STATE_ON | CHIPSET_STATE_ANY_SUSPEND))
+		hook_call_deferred(&base_detect_deferred_data, timeout);
 };
 DECLARE_HOOK(HOOK_INIT, base_detect_deferred, HOOK_PRIO_INIT_ADC + 1);
 
+static void power_on_base(void)
+{
+	hook_call_deferred(&base_detect_deferred_data, 0);
+}
+DECLARE_HOOK(HOOK_CHIPSET_STARTUP, power_on_base, HOOK_PRIO_DEFAULT);
+
+static void power_off_base(void)
+{
+	base_power_enable(0);
+}
+DECLARE_HOOK(HOOK_CHIPSET_SHUTDOWN, power_off_base, HOOK_PRIO_DEFAULT);
+
 static uint8_t base_power_on_attempts;
 static void clear_base_power_on_attempts_deferred(void)
 {
@@ -207,7 +237,7 @@ static void check_and_reapply_base_power_deferred(void)
 
 	if (base_power_on_attempts < POWER_FAULT_MAX_RETRIES) {
 		CPRINTS("Reapply base pwr");
-		gpio_set_level(GPIO_BASE_PWR_EN, 1);
+		base_power_enable(1);
 		base_power_on_attempts++;
 
 		hook_call_deferred(&clear_base_power_on_attempts_deferred_data,
@@ -225,7 +255,7 @@ void base_pwr_fault_interrupt(enum gpio_signal s)
 	if (fault_detected) {
 		/* Turn off base power. */
 		CPRINTS("Base Pwr Flt!");
-		gpio_set_level(GPIO_BASE_PWR_EN, 0);
+		base_power_enable(0);
 
 		/*
 		 * Try and apply power in a bit if maybe it was just a temporary