serial: allow callback setting to be exclusive

Both the IRQ API and Asynchronous API support callback.
However, since they are both interrupt driven, having
callbacks on both API would interfere with each other
in almost all cases. So this adds a kconfig to signal
that the callbacks should be exclusive to each other.
In other words, if one is set, the other should not
be active. Drivers implementing both APIs have been
updated to remove the callbacks from the other API.
Though, this still leaves the option to disable
the kconfig and allows both APIs to have callbacks
if one desires.

Fixes zephyrproject-rtos#48606

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

doc/hardware/peripherals/uart.rst

@@ -28,6 +28,15 @@ The Asynchronous API allows to read and write data in the background using DMA
 without interrupting the MCU at all. However, the setup is more complex
 than the other methods.
 
+.. warning::
+
+   Interrupt-driven API and the Asynchronous API should NOT be used at
+   the same time, since both APIs require hardware interrupts to function
+   properly, using the callbacks for both APIs would result in interference
+   between each other. :kconfig:option:`CONFIG_UART_EXCLUSIVE_API_CALLBACKS`
+   is enabled by default so that only the callbacks associated with one API
+   is active at a time.
+
 
 Configuration Options
 *********************

drivers/serial/Kconfig

@@ -76,6 +76,21 @@ config UART_INTERRUPT_DRIVEN
 	  This option enables interrupt support for UART allowing console
 	  input and other UART based drivers.
 
+config UART_EXCLUSIVE_API_CALLBACKS
+	bool "Use exclusive callbacks for multiple APIs"
+	depends on UART_ASYNC_API && UART_INTERRUPT_DRIVEN
+	default y
+	help
+	  When multiple set of APIs support callbacks, enabling this
+	  option will result in only the callbacks of one set of API
+	  being active at a time. Setting a new callback to one set of
+	  API will remove callbacks to other set of APIs. For example,
+	  calling uart_callback_set() would disable the callback
+	  previously set via uart_irq_callback_set().
+
+	  Says yes unless you are absolutely sure you know what you are
+	  doing and promise not to file bug when things do not work out.
+
 config UART_LINE_CTRL
 	bool "Serial Line Control API"
 	help

drivers/serial/uart_esp32.c

@@ -435,6 +435,11 @@ static void uart_esp32_irq_callback_set(const struct device *dev, uart_irq_callb
 
 	data->irq_cb = cb;
 	data->irq_cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async.cb = NULL;
+	data->async.user_data = NULL;
+#endif
 }
 
 #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
@@ -662,6 +667,11 @@ static int uart_esp32_async_callback_set(const struct device *dev, uart_callback
 	data->async.cb = callback;
 	data->async.user_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->irq_cb = NULL;
+	data->irq_cb_data = NULL;
+#endif
+
 	return 0;
 }
 

drivers/serial/uart_mcux_flexcomm.c

@@ -279,6 +279,11 @@ static void mcux_flexcomm_irq_callback_set(const struct device *dev,
 
 	data->irq_callback = cb;
 	data->irq_cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async_callback = NULL;
+	data->async_cb_data = NULL;
+#endif
 }
 #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
 
@@ -400,6 +405,12 @@ static int mcux_flexcomm_uart_callback_set(const struct device *dev,
 	data->async_callback = callback;
 	data->async_cb_data = user_data;
 
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->irq_callback = NULL;
+	data->irq_cb_data = NULL;
+#endif
+
 	return 0;
 }
 

drivers/serial/uart_mcux_lpuart.c

@@ -370,6 +370,11 @@ static void mcux_lpuart_irq_callback_set(const struct device *dev,
 
 	data->callback = cb;
 	data->cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async.user_callback = NULL;
+	data->async.user_data = NULL;
+#endif
 }
 
 #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
@@ -661,6 +666,11 @@ static int mcux_lpuart_callback_set(const struct device *dev, uart_callback_t ca
 	data->async.user_callback = callback;
 	data->async.user_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->callback = NULL;
+	data->cb_data = NULL;
+#endif
+
 	return 0;
 }
 

drivers/serial/uart_nrfx_uart.c

@@ -405,6 +405,11 @@ static int uart_nrfx_callback_set(const struct device *dev,
 	uart0_cb.callback = callback;
 	uart0_cb.user_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	irq_callback = NULL;
+	irq_cb_data = NULL;
+#endif
+
 	return 0;
 }
 
@@ -923,6 +928,11 @@ static void uart_nrfx_irq_callback_set(const struct device *dev,
 	(void)dev;
 	irq_callback = cb;
 	irq_cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	uart0_cb.callback = NULL;
+	uart0_cb.user_data = NULL;
+#endif
 }
 
 /**

drivers/serial/uart_nrfx_uarte.c

@@ -937,6 +937,11 @@ static int uarte_nrfx_callback_set(const struct device *dev,
 	data->async->user_callback = callback;
 	data->async->user_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->int_driven->cb = NULL;
+	data->int_driven->cb_data = NULL;
+#endif
+
 	return 0;
 }
 
@@ -1675,6 +1680,11 @@ static void uarte_nrfx_irq_callback_set(const struct device *dev,
 
 	data->int_driven->cb = cb;
 	data->int_driven->cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async->user_callback = NULL;
+	data->async->user_data = NULL;
+#endif
 }
 #endif /* UARTE_INTERRUPT_DRIVEN */
 

drivers/serial/uart_sam0.c

@@ -935,6 +935,11 @@ static void uart_sam0_irq_callback_set(const struct device *dev,
 
 	dev_data->cb = cb;
 	dev_data->cb_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	dev_data->async_cb = NULL;
+	dev_data->async_cb_data = NULL;
+#endif
 }
 #endif
 
@@ -949,6 +954,11 @@ static int uart_sam0_callback_set(const struct device *dev,
 	dev_data->async_cb = callback;
 	dev_data->async_cb_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	dev_data->cb = NULL;
+	dev_data->cb_data = NULL;
+#endif
+
 	return 0;
 }
 

drivers/serial/uart_stm32.c

@@ -904,6 +904,11 @@ static void uart_stm32_irq_callback_set(const struct device *dev,
 
 	data->user_cb = cb;
 	data->user_data = cb_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async_cb = NULL;
+	data->async_user_data = NULL;
+#endif
 }
 
 #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
@@ -1125,6 +1130,11 @@ static int uart_stm32_async_callback_set(const struct device *dev,
 	data->async_cb = callback;
 	data->async_user_data = user_data;
 
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->user_cb = NULL;
+	data->user_data = NULL;
+#endif
+
 	return 0;
 }
 

drivers/serial/uart_xmc4xxx.c

@@ -360,6 +360,11 @@ static void uart_xmc4xxx_irq_callback_set(const struct device *dev,
 
 	data->user_cb = cb;
 	data->user_data = user_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->async_cb = NULL;
+	data->async_user_data = NULL;
+#endif
 }
 
 #define NVIC_ISPR_BASE 0xe000e200u
@@ -599,6 +604,12 @@ static int uart_xmc4xxx_async_callback_set(const struct device *dev, uart_callba
 
 	data->async_cb = callback;
 	data->async_user_data = user_data;
+
+#if defined(CONFIG_UART_EXCLUSIVE_API_CALLBACKS)
+	data->user_cb = NULL;
+	data->user_data = NULL;
+#endif
+
 	return 0;
 }