ap_pwrseq: Add ADC interrupt enable/disable

Add interrupt enable/disable to the ADC power signal
handling, so that the ADC can be turned off when the
CPU is off, to save power.

BUG=b:228535753
TEST=zmake build nivviks; flash & run
BRANCH=none

Signed-off-by: Andrew McRae <amcrae@google.com>
Change-Id: If1cc4b52e215115d2a0eb3b30dae29a7a0fa8833
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3577313
Reviewed-by: Peter Marheine <pmarheine@chromium.org>

3 files changed, 114 insertions, 36 deletions

diff --git a/zephyr/subsys/ap_pwrseq/include/signal_adc.h b/zephyr/subsys/ap_pwrseq/include/signal_adc.h
index 92570beef1..294a3455a3 100644
--- a/zephyr/subsys/ap_pwrseq/include/signal_adc.h
+++ b/zephyr/subsys/ap_pwrseq/include/signal_adc.h
@@ -41,6 +41,30 @@ DT_FOREACH_STATUS_OKAY(intel_ap_pwrseq_adc, PWR_ADC_ENUM)
 int power_signal_adc_get(enum pwr_sig_adc adc);
 
 /**
+ * @brief Enable the ADC interrupt
+ *
+ * This will not only enable the interrupt driven update
+ * of this signal, but will also enable the ADC itself.
+ *
+ * @param signal The pwr_sig_adc to enable.
+ * @return 0 if successful
+ * @return -error if failed
+ */
+int power_signal_adc_enable_int(enum pwr_sig_adc adc);
+
+/**
+ * @brief Disable the ADC interrupt
+ *
+ * This will disable the interrupt updating of this signal, and will
+ * also disable the ADC from running.
+ *
+ * @param signal The pwr_sig_adc to disable.
+ * @return 0 if successful
+ * @return -error if failed
+ */
+int power_signal_adc_disable_int(enum pwr_sig_adc adc);
+
+/**
  * @brief Initialize the ADCs for the power signals.
  */
 void power_signal_adc_init(void);
diff --git a/zephyr/subsys/ap_pwrseq/power_signals.c b/zephyr/subsys/ap_pwrseq/power_signals.c
index e6bdb05954..d103c4c56b 100644
--- a/zephyr/subsys/ap_pwrseq/power_signals.c
+++ b/zephyr/subsys/ap_pwrseq/power_signals.c
@@ -246,6 +246,10 @@ int power_signal_enable_interrupt(enum power_signal signal)
 	case PWR_SIG_SRC_GPIO:
 		return power_signal_gpio_enable_int(cp->src_enum);
 #endif
+#if HAS_ADC_SIGNALS
+	case PWR_SIG_SRC_ADC:
+		return power_signal_adc_enable_int(cp->src_enum);
+#endif
 	}
 }
 
@@ -265,6 +269,10 @@ int power_signal_disable_interrupt(enum power_signal signal)
 	case PWR_SIG_SRC_GPIO:
 		return power_signal_gpio_disable_int(cp->src_enum);
 #endif
+#if HAS_ADC_SIGNALS
+	case PWR_SIG_SRC_ADC:
+		return power_signal_adc_disable_int(cp->src_enum);
+#endif
 	}
 }
 
diff --git a/zephyr/subsys/ap_pwrseq/signal_adc.c b/zephyr/subsys/ap_pwrseq/signal_adc.c
index 9f07b73964..7ee394a623 100644
--- a/zephyr/subsys/ap_pwrseq/signal_adc.c
+++ b/zephyr/subsys/ap_pwrseq/signal_adc.c
@@ -33,42 +33,70 @@ static const struct adc_config config[] = {
 DT_FOREACH_STATUS_OKAY(MY_COMPAT, INIT_ADC_CONFIG)
 };
 
-static atomic_t value[ARRAY_SIZE(config)];
+/*
+ * Bit allocations for atomic state
+ */
+enum {
+	ADC_BIT_VALUE = 0,
+	ADC_BIT_LOW_ENABLED = 1,
+	ADC_BIT_HIGH_ENABLED = 2
+};
+
+atomic_t adc_state[ARRAY_SIZE(config)];
+
+static void set_trigger(const struct device *dev,
+			atomic_t *state,
+			int bit,
+			bool enable)
+{
+	/*
+	 * Only enable or disable if the trigger is not
+	 * already enabled or disabled.
+	 */
+	if (enable
+		? !atomic_test_and_set_bit(state, bit)
+		: atomic_test_and_clear_bit(state, bit)) {
+		struct sensor_value val;
+
+		val.val1 = enable;
+		sensor_attr_set(dev,
+				SENSOR_CHAN_VOLTAGE,
+				SENSOR_ATTR_ALERT,
+				&val);
+	}
+}
+
+static void set_low_trigger(enum pwr_sig_adc adc, bool enable)
+{
+	set_trigger(config[adc].dev_trig_low,
+		    &adc_state[adc],
+		    ADC_BIT_LOW_ENABLED,
+		    enable);
+
+}
+
+static void set_high_trigger(enum pwr_sig_adc adc, bool enable)
+{
+	set_trigger(config[adc].dev_trig_high,
+		    &adc_state[adc],
+		    ADC_BIT_HIGH_ENABLED,
+		    enable);
+}
 
 static void trigger_high(enum pwr_sig_adc adc)
 {
-	struct sensor_value val;
-
-	atomic_set_bit(&value[adc], 0);
-	val.val1 = false;
-	sensor_attr_set(config[adc].dev_trig_high,
-			SENSOR_CHAN_VOLTAGE,
-			SENSOR_ATTR_ALERT,
-			&val);
-	val.val1 = true;
-	sensor_attr_set(config[adc].dev_trig_low,
-			SENSOR_CHAN_VOLTAGE,
-			SENSOR_ATTR_ALERT,
-			&val);
+	atomic_set_bit(&adc_state[adc], ADC_BIT_VALUE);
+	set_low_trigger(adc, true);
+	set_high_trigger(adc, false);
 	LOG_DBG("power signal adc%d is HIGH", adc);
 	power_signal_interrupt(config[adc].signal, 1);
 }
 
 static void trigger_low(enum pwr_sig_adc adc)
 {
-	struct sensor_value val;
-
-	atomic_clear_bit(&value[adc], 0);
-	val.val1 = false;
-	sensor_attr_set(config[adc].dev_trig_low,
-			SENSOR_CHAN_VOLTAGE,
-			SENSOR_ATTR_ALERT,
-			&val);
-	val.val1 = true;
-	sensor_attr_set(config[adc].dev_trig_high,
-			SENSOR_CHAN_VOLTAGE,
-			SENSOR_ATTR_ALERT,
-			&val);
+	atomic_clear_bit(&adc_state[adc], ADC_BIT_VALUE);
+	set_low_trigger(adc, false);
+	set_high_trigger(adc, true);
 	LOG_DBG("power signal adc%d is LOW", adc);
 	power_signal_interrupt(config[adc].signal, 0);
 }
@@ -78,7 +106,32 @@ int power_signal_adc_get(enum pwr_sig_adc adc)
 	if (adc < 0 || adc >= ARRAY_SIZE(config)) {
 		return -EINVAL;
 	}
-	return !!value[adc];
+	return atomic_test_bit(&adc_state[adc], ADC_BIT_VALUE);
+}
+
+int power_signal_adc_enable_int(enum pwr_sig_adc adc)
+{
+	if (adc < 0 || adc >= ARRAY_SIZE(config)) {
+		return -EINVAL;
+	}
+
+	/* Only need to enable relevant trigger depending on current state */
+	if (atomic_test_bit(&adc_state[adc], ADC_BIT_VALUE)) {
+		set_low_trigger(adc, true);
+	} else {
+		set_high_trigger(adc, true);
+	}
+	return 0;
+}
+
+int power_signal_adc_disable_int(enum pwr_sig_adc adc)
+{
+	if (adc < 0 || adc >= ARRAY_SIZE(config)) {
+		return -EINVAL;
+	}
+	set_low_trigger(adc, false);
+	set_high_trigger(adc, false);
+	return 0;
 }
 
 /*
@@ -110,7 +163,6 @@ void power_signal_adc_init(void)
 		.type = SENSOR_TRIG_THRESHOLD,
 		.chan = SENSOR_CHAN_VOLTAGE
 	};
-	struct sensor_value val;
 	sensor_trigger_handler_t low_cb[] = {
 		DT_FOREACH_STATUS_OKAY_VARGS(MY_COMPAT, ADC_CB_COMMA, low)
 	};
@@ -123,13 +175,7 @@ void power_signal_adc_init(void)
 		/* Set high and low trigger callbacks */
 		sensor_trigger_set(config[i].dev_trig_high, &trig, high_cb[i]);
 		sensor_trigger_set(config[i].dev_trig_low, &trig, low_cb[i]);
-
-		/* Enable high trigger callback only */
-		val.val1 = true;
-		sensor_attr_set(config[i].dev_trig_high,
-				SENSOR_CHAN_VOLTAGE,
-				SENSOR_ATTR_ALERT,
-				&val);
+		power_signal_adc_enable_int(i);
 	}
 }