it8xxx2/shi: wrap pm policy state get/put

When CONFIG_ASSERT is enabled, assertion for unbalanced state lock
get/put is triggered. This commit leverages shi drivers from other
SoCs to resolve the assertion.

Signed-off-by: Dino Li <[email protected]>

Author: Dino-Li

subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_ite.c

@@ -63,23 +63,64 @@ struct shi_it8xxx2_cfg {
 	const struct gpio_dt_spec cs;
 };
 
+enum shi_ite_pm_policy_state_flag {
+	SHI_ITE_PM_POLICY_FLAG,
+	SHI_ITE_PM_POLICY_FLAG_COUNT,
+};
+
 struct shi_it8xxx2_data {
 	/* Peripheral data */
 	struct ec_host_cmd_rx_ctx *rx_ctx;
 	struct ec_host_cmd_tx_buf *tx;
 	struct gpio_callback cs_cb;
+	struct k_work_delayable cs_off_put;
 	/* Current state */
 	enum shi_state_machine shi_state;
 	/* Buffers */
 	uint8_t in_msg[SPI_RX_MAX_FIFO_SIZE] __aligned(4);
 	uint8_t out_msg[SPI_TX_MAX_FIFO_SIZE] __aligned(4);
+	ATOMIC_DEFINE(pm_policy_state_flag, SHI_ITE_PM_POLICY_FLAG_COUNT);
 };
 
 struct ec_host_cmd_shi_ite_ctx {
 	/* SHI device instance */
 	const struct device *dev;
 };
 
+static void shi_ite_pm_policy_state_lock_get(struct shi_it8xxx2_data *data,
+					     enum shi_ite_pm_policy_state_flag flag)
+{
+	if (atomic_test_and_set_bit(data->pm_policy_state_flag, flag) == 0) {
+		pm_policy_state_lock_get(PM_STATE_STANDBY, PM_ALL_SUBSTATES);
+		k_work_reschedule(&data->cs_off_put, K_SECONDS(3));
+	}
+}
+
+static void shi_ite_pm_policy_state_lock_put(struct shi_it8xxx2_data *data,
+					     enum shi_ite_pm_policy_state_flag flag)
+{
+	if (atomic_test_and_clear_bit(data->pm_policy_state_flag, flag) == 1) {
+		pm_policy_state_lock_put(PM_STATE_STANDBY, PM_ALL_SUBSTATES);
+		k_work_cancel_delayable(&data->cs_off_put);
+	}
+}
+
+/*
+ * When AP is In S0 state, AP assert CS of SPI for a new command transaction.
+ * Under the condition, SoC will not enter deep sleep until AP de-assert the CS.
+ * But If AP is powered off (G3 state) CS will go low (assert CS).
+ * This assertion will prevent SoC from entering deep sleep but the assertion
+ * is not for starting a new command transaction.
+ * This handler is used to resolve the situation.
+ */
+static void cs_off_put_handler(struct k_work *item)
+{
+	struct k_work_delayable *dwork = k_work_delayable_from_work(item);
+	struct shi_it8xxx2_data *data = CONTAINER_OF(dwork, struct shi_it8xxx2_data, cs_off_put);
+
+	shi_ite_pm_policy_state_lock_put(data, SHI_ITE_PM_POLICY_FLAG);
+}
+
 static const uint8_t out_preamble[EC_SHI_PREAMBLE_LENGTH] = {
 	EC_SHI_PROCESSING,
 	EC_SHI_PROCESSING,
@@ -293,7 +334,7 @@ static void shi_ite_int_handler(const struct device *dev)
 		/* CS# is deasserted, so write clear all slave status */
 		IT83XX_SPI_ISR = 0xff;
 		/* Allow the MCU to go into lower power mode */
-		pm_policy_state_lock_put(PM_STATE_STANDBY, PM_ALL_SUBSTATES);
+		shi_ite_pm_policy_state_lock_put(data, SHI_ITE_PM_POLICY_FLAG);
 	}
 
 	/*
@@ -319,7 +360,7 @@ void shi_ite_cs_callback(const struct device *port, struct gpio_callback *cb, gp
 	}
 
 	/* Prevent the MCU from sleeping during the transmission */
-	pm_policy_state_lock_get(PM_STATE_STANDBY, PM_ALL_SUBSTATES);
+	shi_ite_pm_policy_state_lock_get(data, SHI_ITE_PM_POLICY_FLAG);
 
 	/* Move to processing state */
 	shi_ite_set_state(data, SHI_STATE_PROCESSING);
@@ -436,6 +477,8 @@ static int shi_ite_init(const struct device *dev)
 		return -EINVAL;
 	}
 
+	k_work_init_delayable(&data->cs_off_put, cs_off_put_handler);
+
 	pm_device_init_suspended(dev);
 	return pm_device_runtime_enable(dev);
 }