rw6xx: Add Support for Standby Power Mode

drivers/serial/uart_mcux_flexcomm.c

@@ -14,7 +14,9 @@
 #include <zephyr/device.h>
 #include <zephyr/drivers/uart.h>
 #include <zephyr/drivers/clock_control.h>
+#include <zephyr/pm/policy.h>
 #include <zephyr/irq.h>
+#include <zephyr/pm/device.h>
 #include <fsl_usart.h>
 #include <soc.h>
 #include <fsl_device_registers.h>
@@ -86,8 +88,33 @@ struct mcux_flexcomm_data {
 #ifdef CONFIG_UART_USE_RUNTIME_CONFIGURE
 	struct uart_config uart_config;
 #endif
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+	bool pm_policy_state_lock;
+#endif
 };
 
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+static void mcux_flexcomm_pm_policy_state_lock_get(const struct device *dev)
+{
+	struct mcux_flexcomm_data *data = dev->data;
+
+	if (!data->pm_policy_state_lock) {
+		data->pm_policy_state_lock = true;
+		pm_policy_device_power_lock_get(dev);
+	}
+}
+
+static void mcux_flexcomm_pm_policy_state_lock_put(const struct device *dev)
+{
+	struct mcux_flexcomm_data *data = dev->data;
+
+	if (data->pm_policy_state_lock) {
+		data->pm_policy_state_lock = false;
+		pm_policy_device_power_lock_put(dev);
+	}
+}
+#endif
+
 static int mcux_flexcomm_poll_in(const struct device *dev, unsigned char *c)
 {
 	const struct mcux_flexcomm_config *config = dev->config;
@@ -179,6 +206,14 @@ static void mcux_flexcomm_irq_tx_enable(const struct device *dev)
 	const struct mcux_flexcomm_config *config = dev->config;
 	uint32_t mask = kUSART_TxLevelInterruptEnable;
 
+	/* Indicates that this device started a transaction that should
+	 * not be interrupted by putting the SoC in states that would
+	 * interfere with this transfer.
+	 */
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+	mcux_flexcomm_pm_policy_state_lock_get(dev);
+#endif
+
 	USART_EnableInterrupts(config->base, mask);
 }
 
@@ -187,6 +222,10 @@ static void mcux_flexcomm_irq_tx_disable(const struct device *dev)
 	const struct mcux_flexcomm_config *config = dev->config;
 	uint32_t mask = kUSART_TxLevelInterruptEnable;
 
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+	mcux_flexcomm_pm_policy_state_lock_put(dev);
+#endif
+
 	USART_DisableInterrupts(config->base, mask);
 }
 
@@ -467,11 +506,19 @@ static int mcux_flexcomm_uart_tx(const struct device *dev, const uint8_t *buf,
 	/* Enable TX DMA requests */
 	USART_EnableTxDMA(config->base, true);
 
+	/* Do not allow the system to suspend until the transmission has completed */
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+	mcux_flexcomm_pm_policy_state_lock_get(dev);
+#endif
+
 	/* Trigger the DMA to start transfer */
 	ret = dma_start(config->tx_dma.dev, config->tx_dma.channel);
 	if (ret) {
 		irq_unlock(key);
-		return ret;
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+		mcux_flexcomm_pm_policy_state_lock_put(dev);
+#endif
+	return ret;
 	}
 
 	/* Schedule a TX abort for @param timeout */
@@ -993,15 +1040,18 @@ static void mcux_flexcomm_isr(const struct device *dev)
 			data->tx_data.xfer_buf = NULL;
 
 			async_user_callback(dev, &tx_done_event);
+
+#ifdef CONFIG_PM_POLICY_DEVICE_CONSTRAINTS
+			mcux_flexcomm_pm_policy_state_lock_put(dev);
+#endif
 		}
 
 	}
 #endif /* CONFIG_UART_ASYNC_API */
 }
 #endif /* CONFIG_UART_MCUX_FLEXCOMM_ISR_SUPPORT */
 
-
-static int mcux_flexcomm_init(const struct device *dev)
+static int mcux_flexcomm_init_common(const struct device *dev)
 {
 	const struct mcux_flexcomm_config *config = dev->config;
 #ifdef CONFIG_UART_USE_RUNTIME_CONFIGURE
@@ -1067,6 +1117,42 @@ static int mcux_flexcomm_init(const struct device *dev)
 	return 0;
 }
 
+static uint32_t usart_intenset;
+static int mcux_flexcomm_pm_action(const struct device *dev, enum pm_device_action action)
+{
+	const struct mcux_flexcomm_config *config = dev->config;
+
+	usart_intenset = USART_GetEnabledInterrupts(config->base);
+
+	switch (action) {
+	case PM_DEVICE_ACTION_RESUME:
+		break;
+	case PM_DEVICE_ACTION_SUSPEND:
+		break;
+	case PM_DEVICE_ACTION_TURN_OFF:
+		break;
+	case PM_DEVICE_ACTION_TURN_ON:
+		int ret = mcux_flexcomm_init_common(dev);
+
+		if (ret) {
+			return ret;
+		}
+		USART_EnableInterrupts(config->base, usart_intenset);
+		break;
+	default:
+		return -ENOTSUP;
+	}
+	return 0;
+}
+
+static int mcux_flexcomm_init(const struct device *dev)
+{
+	/* Rest of the init is done from the PM_DEVICE_TURN_ON action
+	 * which is invoked by pm_device_driver_init().
+	 */
+	return pm_device_driver_init(dev, mcux_flexcomm_pm_action);
+}
+
 static DEVICE_API(uart, mcux_flexcomm_driver_api) = {
 	.poll_in = mcux_flexcomm_poll_in,
 	.poll_out = mcux_flexcomm_poll_out,
@@ -1202,9 +1288,11 @@ static const struct mcux_flexcomm_config mcux_flexcomm_##n##_config = {		\
 										\
 	static const struct mcux_flexcomm_config mcux_flexcomm_##n##_config;	\
 										\
+	PM_DEVICE_DT_INST_DEFINE(n, mcux_flexcomm_pm_action);			\
+										\
 	DEVICE_DT_INST_DEFINE(n,						\
-			    mcux_flexcomm_init,					\
-			    NULL,						\
+			    &mcux_flexcomm_init,				\
+			    PM_DEVICE_DT_INST_GET(n),				\
 			    &mcux_flexcomm_##n##_data,				\
 			    &mcux_flexcomm_##n##_config,			\
 			    PRE_KERNEL_1,					\

dts/arm/nxp/nxp_rw6xx_common.dtsi

@@ -225,6 +225,7 @@
 		resets = <&rstctl1 NXP_SYSCON_RESET(0, 8)>;
 		dmas = <&dma0 0>, <&dma0 1>;
 		dma-names = "rx", "tx";
+		zephyr,disabling-power-states = <&suspend>;
 		status = "disabled";
 	};
 
@@ -236,6 +237,7 @@
 		resets = <&rstctl1 NXP_SYSCON_RESET(0, 9)>;
 		dmas = <&dma0 2>, <&dma0 3>;
 		dma-names = "rx", "tx";
+		zephyr,disabling-power-states = <&suspend>;
 		status = "disabled";
 	};
 
@@ -247,6 +249,7 @@
 		resets = <&rstctl1 NXP_SYSCON_RESET(0, 10)>;
 		dmas = <&dma0 4>, <&dma0 5>;
 		dma-names = "rx", "tx";
+		zephyr,disabling-power-states = <&suspend>;
 		status = "disabled";
 	};
 
@@ -258,6 +261,7 @@
 		resets = <&rstctl1 NXP_SYSCON_RESET(0, 11)>;
 		dmas = <&dma0 6>, <&dma0 7>;
 		dma-names = "rx", "tx";
+		zephyr,disabling-power-states = <&suspend>;
 		status = "disabled";
 	};
 
@@ -269,6 +273,7 @@
 		resets = <&rstctl1 NXP_SYSCON_RESET(0, 22)>;
 		dmas = <&dma0 26>, <&dma0 27>;
 		dma-names = "rx", "tx";
+		zephyr,disabling-power-states = <&suspend>;
 		status = "disabled";
 	};