[nrf fromlist] drivers: serial: nrfx_uarte: Add support for device deinit

Add device deinit function. Support is optional as it is not widely
used and it enables pinctrl sleep state so it impacts memory footprint.

Upstream PR #: 93273

Signed-off-by: Krzysztof Chruściński <[email protected]>

Author: nordic-krch

drivers/serial/Kconfig.nrfx

@@ -43,6 +43,13 @@ config UART_NRFX_UARTE_NO_IRQ
 	  When enabled, then interrupt handler is not used at all and it is possible
 	  to get to the lowest power state after uart_poll_out if receiver is not used.
 
+config UART_NRFX_UARTE_DEINIT
+	bool "Support deinit"
+	depends on UART_NRFX_UARTE
+	imply PINCTRL_KEEP_SLEEP_STATE
+	help
+	  When enabled then UART driver support device_deinit.
+
 config UART_NRFX_UARTE_LEGACY_SHIM
 	bool "Legacy UARTE shim"
 	depends on UART_NRFX_UARTE

drivers/serial/uart_nrfx_uarte.c

@@ -2603,6 +2603,22 @@ static int uarte_instance_init(const struct device *dev,
 	return pm_device_driver_init(dev, uarte_nrfx_pm_action);
 }
 
+static int uarte_instance_deinit(const struct device *dev)
+{
+	if (IS_ENABLED(CONFIG_PM_DEVICE)) {
+		enum pm_device_state state;
+
+		/* PM must have suspended the device before driver can be deinitialized. */
+		(void)pm_device_state_get(dev, &state);
+		return (state == PM_DEVICE_STATE_SUSPENDED) || (state == PM_DEVICE_STATE_OFF) ?
+		       0 : -EBUSY;
+	}
+
+	uarte_pm_suspend(dev);
+
+	return 0;
+}
+
 #define UARTE_GET_ISR(idx) \
 	COND_CODE_1(CONFIG_UART_##idx##_ASYNC, (uarte_nrfx_isr_async), (uarte_nrfx_isr_int))
 
@@ -2793,8 +2809,10 @@ static int uarte_instance_init(const struct device *dev,
 	PM_DEVICE_DT_DEFINE(UARTE(idx), uarte_nrfx_pm_action,		       \
 			    UARTE_PM_ISR_SAFE(idx));			       \
 									       \
-	DEVICE_DT_DEFINE(UARTE(idx),					       \
+	DEVICE_DT_DEINIT_DEFINE(UARTE(idx),				       \
 		      uarte_##idx##_init,				       \
+		      IS_ENABLED(CONFIG_UART_NRFX_UARTE_DEINIT) ?	       \
+		       uarte_instance_deinit : NULL,			       \
 		      PM_DEVICE_DT_GET(UARTE(idx)),			       \
 		      &uarte_##idx##_data,				       \
 		      &uarte_##idx##z_config,				       \