- Return -ENOTSUP if the requested state is not supported
- Remove redundant "noop style" functions.
- Use switch everywhere to handle requested state (not necessary in all
drivers, but better take off with consistency in place after current
changes).
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The verb tense for the suspended state was not consistent with other
states. The likely reason: state was being used as a command/action.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The difference between low power and suspend states is a thin blur line
that is is not clear and most drivers have used indistinctly. This patch
converges to the usage of the suspend state for low power, since
contrary to the low power state, it is used by both system and runtime
device PM. The low power state is still kept, but its future is unclear
and needs some discussion.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The device PM control function will only be called if the requested
state is different from the current one. A significant amount of drivers
were checking for state changes, now unnecessary. This patch removes all
this redundant logic.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Since the state is no longer modified by the device PM callback, just
use the state value.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The callback is now invoked to set the device PM state in all cases, so
the usage of ctrl_command is redundant.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The device PM subsystem already holds the device state, so there is no
need to keep duplicates inside the device. The pm_device_state_get has
been refactored to just return the device state. Note that this is still
not safe, but the same applied to the previous implementation. This
problem will be addressed later.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
based on uart rom functions, also enable console driver
on top if this driver enabling logging
Signed-off-by: Felipe Neves <felipe.neves@espressif.com>
Add Atmel sam0 sercom[uart] pinctrl bindings and implements pinctrl at
driver level. It changes all sam0 boards to use new feature and remove
pinmux driver dependency for sercom[uart]. The samples that require a
binding were update to keep consistency and avoid errors.
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
The following device busy APIs:
- device_busy_set()
- device_busy_clear()
- device_busy_check()
- device_any_busy_check()
were used for device PM, so they have been moved to the pm subsystem.
This means they are now prefixed with `pm_` and are defined in
`pm/device.h`.
If device PM is not enabled dummy functions are now provided that do
nothing or return `-ENOSYS`, meaning that the functionality is not
available.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
All the macro for dma-cells are now in the
include/drivers/dma/dma_stm32.h header file.
So the include/dt-bindings/dma/stm32_dma.h is no more
useful and removed from #include.
Signed-off-by: Francois Ramu <francois.ramu@st.com>
The macro to set the element of the dma-cells for each peripheral
are defined in the dma_stm32 header file
and used in the periph driver (as dma client)
Signed-off-by: Francois Ramu <francois.ramu@st.com>
This is the dma V2bis which is particular DMA V2 instance for
stm32F1 and STM32L1 soc series. This DMA does not use the dma slot
Otherwise it is similar to version V2.
Signed-off-by: Francois Ramu <francois.ramu@st.com>
When DMA switches from one buffer to another ENDRX followed by
RXSTARTED is generated. Code flow assumes that ENDRX will be
handled before RXSTARTED but this may not be the case if there
is a short between ENDRX and RXSTARTED and event occurs after
ENDRX event check but before RXSTARTED event check. In that case,
RXSTARTED event is handled first. Such case may happen if there
is a higher priority interrupt that may preempt UARTE interrupt
handler.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
This commit adds a serial dummy driver compatible to vnd,serial.
This is needed that devices can access the uart device in tests
like tests/drivers/build_all/... .
Add myself as codeowner to avoid complicance check failure.
Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>
This commit add the support of "Interrupt driven UART"
to the R-Car UART driver and enable it in the related
Kconfig.
The driver is supporting nearly all the methods that are
described in the "Interrupt driven UART" part of the
uart_driver_api.
This new version of the driver has been tested on
H3ULCB board by running "uart_basic_api" test suite.
Signed-off-by: Aymeric Aillet <aymeric.aillet@iot.bzh>
The callback is not used anymore, so just delete it from the pm_control
callback signature.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
the device PM callback is not used anymore by the device PM subsystem,
so remove it from all drivers/tests using it.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
hal_espressif repository was updated from esp-idf v4.2
to esp-idf v4.3 to allow latest Espressif chips integration.
As a consequence, it added a few changes in drivers
and peripherals. To maintain bisectability, changes in this
PR cannot be split. Here are some details:
wifi: update linker script by adding libphy and new attributes.
spi: update some APIs and fixed missing wait_idle check
west.yml: esp32: update hal to new version
Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>
Move all PM_DEVICE_STATE_* definitions to an enum. The
PM_DEVICE_STATE_SET and PM_DEVICE_STATE_GET definitions have been kept
out of the enum since they do not represent any state. However, their
name has not been changed since they will be removed soon.
All drivers and tests have been adjusted accordingly.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
RXTO event is generated always after ENDRX and driver relies
on assumption that ENDRX event is handled before RXTO. However,
when interrupt is preempted after ENDRX check returned false
and RXTO event is already set handling order would be swapped.
Added addtional check to handle RXTO event only if ENDRX is not
set. If ENDRX is set, it means that it is not yet handled. RXTO
event is not cleared and interrupt will be triggered again and
ENDRX event will be handled first.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
UART CR_SIN interrupt enable/disable are invoked when CONFIG_PM enable.
This removes the guard for UART CR_SIN interrupt enable/disable to fix
the build issue.
Fixed#36520
Signed-off-by: Wealian Liao <WHLIAO@nuvoton.com>
Convert the various device_get_binding() calls used to get the device
clock node to use DEVICE_DT_GET. The latter is processed at link time,
so it should be a bit more efficient.
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
NPCX WIMU CR_SIN is used to wake up soc from NPCX sleep power state.
The wake-up IRQ enabled when UART init. It causes the wake-up IRQ to
generate many extra interrupt events, which causes the system too busy
to handle other events. This PR moves the UART wake-up IRQ enabling
from UART init to npcx_power_enter_system_sleep() to avoid the
interrupt storm.
Signed-off-by: Wealian Liao <WHLIAO@nuvoton.com>
Configured UART/UARTE input pins to have pullups. Otherwise when
uart is disconnected pins are floating and generate receiver
errors.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
Fix typo in configuration phase to prepare the driver
for incoming add of Interrupt driven uart mode.
Signed-off-by: Aymeric Aillet <aymeric.aillet@iot.bzh>
The macros are used to get the pin(s) of a given driver instance. Add
_INST prefix to match convention used by the devicetree.h. The original
macros can now be used to obtain pin(s) of an arbitrary device instance
identified by the nodelabel.
Signed-off-by: Piotr Mienkowski <piotr.mienkowski@gmail.com>
Since we removed various series headers, move stm32 driver
under main driver/pinmux folder.
Take this change into account into various drivers.
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
This kconfig option enables runtime configuration of UART
controllers. This allows application to call uart_configure()
to configure the UART controllers and calling uart_config_get()
to retrieve configuration. If this is disabled, UART controllers
rely on UART driver's initialization function to properly
configure the controller. The main use of this option is mainly
code size reduction.
Fixes#16231
Signed-off-by: Daniel Leung <daniel.leung@intel.com>
Currently zephyr has no means to control access to the uart
driver when it is inactive, e.g. shell is not aware of uart
being in idle state and calls asynchronous api. Add early
return to TX starting procedure if device is idle.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Make custom RTT locking configurable and select it where it is needed.
When using RTT for tracing we want to use the default locking.
Update both segger and tracerecorder modules to support that.
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
Function should return -ENOTSUP when asynchronous api is not
supported by the device.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Deadlock may occur when uart device was put to low power state
while uart_poll_out was in progress. Poll out pends until uarte
is ready to send new byte and it is detected by endtx and txstopped
events being set. When uarte was disabled while poll_out was pending
events were never set and that lead to deadlock. Added a step
in going to low power state in which CPU waits for txstopped event
and only after that uarte peripheral is disabled.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
When using the uart driver with interrupt and async api
at the same time (instance for interrupt and instance for async),
the transmission complete interrupt was handled in the async
handling section, even when interrupt driven api is used.
This caused transmission to not work properly in interrupt mode.
The fix is to move the interrupt mode handling to the begginning
of the isr. If async mode is used then interrupt mode code
will not be run.
Signed-off-by: Shlomi Vaknin <shlomi.39sd@gmail.com>
uarte_enable function was not supporting a case when async
api was enabled but instance did not use it. Added runtime
check for async instance presence.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Driver was failing when interrupt mode was enabled for given
instance but interrupt driven TX part was not used. In that
case uart was not disabled after sending a byte which resulted
in continuous interrupt triggering. Added check for
fifo_fill_lock which is set when uart_fifo_fill is used.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Resetting the dma_tx.buffer_length after the dma_tx.counter
calculation, instead of before.
We need to reset the buffer_length when the transmission is finished,
but in order to give the correct value to the uart_event_tx struct,
we use the dma_tx.buffer_length in the calculation of the
dma_tx.counter, used for the len of the event (number of bytes sent).
I found this problem, when I wanted to use the uart_event_tx.len for
freeing the used space inside a ring buffer (ring_buf_get_finish),
and it didn't work, I logged the values of the uart_event_tx struct,
and found out it always was 0, because the buffer_length was 0,
and the whole buffer was transmitted (stat.pending_length also 0).
Signed-off-by: Prema Jonathan van Win <jonathanvanwin@gmail.com>
In case of the following sequence of UART events:
- UART_ENDRX
- UART_RXRDY
- TIMER_RXTIMEOUT
The application receives one more byte that was received,
due to RX counter alignment upon ENDRX event.
The proposed fix moves the RX byte counter alignment to the
RX timeout event handler.
Signed-off-by: Tomasz Chyrowicz <tomasz.chyrowicz@nordicsemi.no>
If we try and build the MiV uart driver with interrupt support enabled
we get some errors related to code that hasn't been updated. Fix the
compile errors and add SERIAL_SUPPORT_INTERRUPT to the Kconfig to
hopefully catch these issues in the future
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
The context parameter used across device power management is
actually the power state. Just use it and avoid a lot of
unnecessary casts.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
This patch add support for polling based UART
on the Renesas R-Car SCIF (Serial Communication Interface
with FIFO)
This hardware block can be found on various Renesas R-Car
SoC series.
It allows to get console on R-Car Gen3 H3ULCB board.
Signed-off-by: Aymeric Aillet <aymeric.aillet@iot.bzh>
Avoid calling PPI driver when enhanced poll functionality is
disabled. Fixing a case when driver failed to compile when
enhanced poll is disabled for all instances.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
NRFX UARTE would write to user supplied buffer on IRQ without checking
whether or not the supplied buffer had available space left to write
one char
Signed-off-by: Arne Edholm <arne.edholm@assaabloy.com>
Automatic collision detection for half-duplex mode can be enabled
by setting `collision-detection` proprety for uart hardware
in the dts file. If the transmitted bit does not match the received
bit an error is raised. This is useful in RS-485 half-duplex mode.
Signed-off-by: Arvin Farahmand <arvinf@ip-logix.com>
Current Cypress PSoC-6 serial driver only works using polling mode.
Add serial driver interrupt routines to allow use of interrupts.
Signed-off-by: Gerson Fernando Budke <gerson.budke@atl-electronics.com>
The current serial driver uses hard code configuration. Rework driver
to use pinctrl and enable full configuration from device tree.
Signed-off-by: Gerson Fernando Budke <gerson.budke@atl-electronics.com>
If there is a UARTE receive error (e.g. framing or break), the RXTO
event may never come. Check error event too, to avoid an infinite loop.
Signed-off-by: Jim Paris <jim@jim.sh>
Replace all existing deprecated API with the recommended alternative.
Fixes#34102
Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>
With some additional macro-magic we can remove the CMake-based header
file template feature, and instead take advantage of the usual
DT_INST_FOREACH_STATUS_OKAY() macro.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
There are no boards that need hard-coded interrupts so just remove this
build-time conditional branch. The way going forward is that all PCIe
devices should always use PCIE_IRQ_DETECT.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
The structure is now k_work_delayable.
The init function is now k_work_init_delayable.
The submit function is now the k_work_reschedule.
The cancel function is now the k_work_cancel_delayable.
Signed-off-by: Francois Ramu <francois.ramu@st.com>
If we are building the driver with CONFIG_UART_INTERRUPT_DRIVEN=n
we need to ifdef around the decleration of uart_cmsdk_apb_isr()
or we'll get a compiler warning.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
This CL adds support for console expired mechanism. It implements the
notification to power management module that the module for console is
in use. If the interval that module doesn't receive any input message
exceeds CONFIG_SOC_POWER_CONSOLE_EXPIRED_TIMEOUT, the power management
module is allowed to enter deep sleep mode. This mechanism gives a
window in which the users can organize console input.
Signed-off-by: Mulin Chao <mlchao@nuvoton.com>
On stm32, the M bits defines the length of the frame between the start
bit and the stop bit, eventually including the parity bit when enabled.
Fix configuration of databits to set correct M bits when parity is
enabled.
This commit tries to address issue zephyrproject-rtos/zephyr#33351
Signed-off-by: Nicolas VINCENT <nicolas.vincent@vossloh.com>
The NRF UARTE has an undocumented feature that when you flush the RX
FIFO, the RXAMOUNT register is not cleared to zero if the FIFO is in
fact empty. This fix is correcting something that was most likely a
typo.
Signed-off-by: Petri Oksanen <petri@iote.ai>
Currently CMSDK uart_irq_is_pending does not use RX and TX interrupt
bits found in INTSTATUS register to check for pending interrutps but
rather it checks for pending interrupts indirectly by checking if RX and
TX buffers are, respectively, full and empty, i.e. it checks bits 0 and
1 in STATE register instead of bits meant for interrupt status found in
INTSTATUS register.
That is particularly problematic because although a RX interrupt implies
a RX buffer full and a TX interrupt implies a TX buffer empty, the
converse is not true. For instance, a TX buffer might be empty for all
data was processed (sent to serial line) already and no further data was
pushed into TX buffer so it remained empty, without generating any
additional TX interrupt. In that case the current uart_irq_is_pending
implementation reports that there are pending interrupts because of the
following logic:
/* Return true if rx buffer full or tx buffer empty */
return (UART_STRUCT(dev)->state & (UART_RX_BF | UART_TX_BF))
!= UART_TX_BF;
which will return 1 (true) if STATE[0] = 0 (TX buffer is empty), since
UART_TX_BF = 1, so STATE[0] != UART_TX_BF, which is true (assuming here
for the sake of simplicity that UART_RX_BF = 0, i.e. RX buffer is empty
too).
One of the common uses of uart_irq_is_pending is in ISR in contructs
like the following:
while (uart_irq_update(dev) && uart_irq_is_pending(dev)) {
if (uart_irq_rx_ready(dev) == 0) { // RX buffer is empty
continue;
}
// RX buffer is full, process RX data
}
So the ISR can be called due to a RX interrupt. Upon finishing
processing the RX data uart_irq_is_pending is called to check for any
pending IRQs and if it happens that TX buffer is empty (like in the case
that TX interrupt is totally disabled) execution gets stuck in the while
loop because TX buffer will never transition to full again, i.e. it will
never have a chance to have STATE[0] = 1, so STATE[0] != UART_TX_BF is
always true.
This commit fixes that undesirable and problematic behavior by making
uart_irq_is_pending use the proper bits in the interrupt status register
(INTSTATUS) to determine if there is indeed any pending interrupts.
That, on the other hand, requires that the pending interrupt flags are
not clearly automatically when calling the ISR, otherwise
uart_irq_is_pending() will return immediatly false on the first call
without any data being really processed inside the ISR. Thus, because
both RX and TX buffer (FIFO) are only 1 byte long, that commit clears
the proper interrupts flags precisely when data is processed (fifo_read
and fifo_fill) or when the interrupts are disabled (irq_rx_disable and
irq_tx_disable).
Finally, that commits also takes the chance to update some comments,
specially regarding the need to "prime" when enabling the TX interrupts
(in uart_cmsdk_apb_irq_tx_enable()). The need to "prime" can be verified
in the CMSDK UART reference implementation in Verilog mentioned in the
"Arm Cortex-M System Design Kit" [0], on p. 4-8, section 4.3,
in cmsdk_apb_uart.v. In that implementation it's also possible to verify
that the FIFO is only 1 byte long, justifying the semantics that if
buffers are not full (STATE[0] or STATE[1] = 0) they are _completly_
empty, holding no data at all.
[0] https://documentation-service.arm.com/static/5e8f1c777100066a414f770b
Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Lowest power consumption can be achieved when uarte peripheral
is disabled when not used. In low power mode, need for both
directions is tracked and if both are no in use peripheral is
disabled. TX disabling is instant but RX requires flushing RX
fifo because data in hardware fifo is lost when peripheral is
re-enabled.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Refactored driver to prepare for low power extension. Functional
change is limited to handling of RX_DISABLED event which is now
generated from RXTO interrupt context after RX is stopped. Previously,
RX was not stopped after the transfer.
Rx flushing function contains hardware limitation workaround.
Workaround is applied only if flushed data is not discarded.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Looking at the data sheet for the npcx section 4.15.5 CR_UART Core
Registers, the UICTRL register that is used in the npcx poll
functions is invalid when running in FIFO mode. Instead, calls to
uart_npcx_poll_in and uart_npcx_poll_out should be redirected to
their respective FIFO read/fill functions (when using interrupts).
Changes:
- When calling uart_poll_in: forward the request to uart_fifo_read.
- When calling uart_poll_out: loop until uart_fifo_fill returns
non-0 (we wrote 1 byte).
Signed-off-by: Yuval Peress <peress@chromium.org>
Simple reorg of the function declarations. This change moves
the interrupt driven functions declared at the bottom of the
uart_npcx.c file to the top, clustered under the same ifdef.
Signed-off-by: Yuval Peress <peress@chromium.org>
The stm32 uart driver fails to build on certian platforms due to
changes introduced by:
commit 3c18bcbf77
Author: Francois Ramu <francois.ramu@st.com>
Date: Wed Jan 27 10:27:33 2021 +0100
drivers: serial: stm32 restore uart after lowpower
Fix this by adding some ifdef's around the code that is specific to the
given platforms that the code works on.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Current implementation of uart_npcx_irq_{tx,rx}_ready always returns
false if the respective interrupt enable bit is not set, which means
that the api cannot be used if the interrupts are temporarily disabled
for whatever reasons, breaking patterns such as [1].
Other uart drivers also seems to not have this check, this patch removes
it from the NPCX driver too.
[1] https://github.com/zephyrproject-rtos/zephyr/blob/master/drivers/console/uart_console.c#L549
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
Since the uart device clock will be stopped after ec entered sleep or
deep sleep state and restore its clock automatically, there is no need
to implement code for suspending and resuming devices manually.
The driver still needs to check the current status of uart device when
it wants to change its power state to LOW or SUSPEND power state. It is
crucial to forbid ec enters sleep or deep sleep state when uart device
is busy with transmitting data. Or we will observe broken characters on
the uart console.
Signed-off-by: Mulin Chao <mlchao@nuvoton.com>
This CL introduces power management driver that improves the efficiency
of ec operation by adjusting the chip’s power consumption to the level
of activity required by the application in npcx series.
The following list summarizes the main properties of the various chip
power states. Please refer the power.c file for more detail.
Main power states in npcx series include:
- Active: Core, RAM and modules operate at the clocks generated by PLL.
- Idle: Enter this state when the Core executes WFI or WFE instruction.
- Sleep: clock is stopped for most of modules but PLL is enabled.
- Deep Sleep: As Sleep mode but PLL is disabled.
- Standby: All power rails are turned off besides standby and battery
power rails.
And this CL implements one power state, PM_STATE_SUSPEND_TO_IDLE, with
two sub-states for Zephyr power management system.
Sub-state 0 - "Deep Sleep" mode with “Instant” wake-up if residency
time is greater or equal to 1 ms
Sub-state 1 - "Deep Sleep" mode with "Standard" wake-up if residency
time is greater or equal to 201 ms
Signed-off-by: Mulin Chao <mlchao@nuvoton.com>
The first uart instance was already devicetree based. To be consistent
convert the second instance to also be devicetree based.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Convert from device_get_binding to DEVICE_DT_GET. In doing this we
no longer need the label in the devicetree node so we remove that.
Removed all __ASSERT_NO_MSG(clk) since we'll get a build error if
DEVICE_DT_GET cant be satisfied, and the clock control api's will
handle reporting if the device_is_ready.
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
The CMSDK uart interrupts for TX and RX can either be treated as a
signel interrupt line or distinct interrupts for TX & RX. In the case
that they were distinct we didn't get the ifdef correct based on DTS.
If we have 2 interrupts in DTS we assume they are for TX & RX and thus
build the interrupt support for distinct TX & RX ISRs.
Also, cleanup handling of UART_2..UART_4 to be similar to how
UART_0/UART_1 code is using DT_INST_IRQN(x).
Fixes#30770Fixes#25601
Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
Add posibility to configure UART_X device
based on board dts config.
Enable uart clock only if node is enabled
Signed-off-by: Pavlo Hamov <pasha.gamov@gmail.com>
Fixes: "WARNING:CONSTANT_COMPARISON: Comparisons should place the
constant on the right side of the test"
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
STM32 uart driver doesn't support 9bits transactions in any case,
so remove case were it was declared as supported.
Fixes#31799
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>
If statement was unconditionally reading a field from async struct
while pointer to this struct may be null if asynchronous API is
enabled but given driver instance is not using it.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
Gracefully shutdown the UARTE peripheral when the async API is used.
Failure to do so results in the driver being unusable when powered back
up as the required events (ENDTX & TXSTOPPED) are not set. This also
ensures that the last byte sent out via `poll_out` is properly output
on the serial line before powering down.
Fixes#31930.
Signed-off-by: Jordan Yates <jordan.yates@data61.csiro.au>
