drivers uart_native_posix: rename to native_pty and support N instances

Rename the driver from uart_native_posix to uart_native_pty.
Including renaming the DTS compatible, and kconfig options, deprecating
the old ones.

And refactor the driver, generalizing it, so we can have any number of
instances.
Note that, unfortunately generalizing to N instances cannot be done
without a degree of backwards compatibility breakage: This driver was
born with all its configuration and selection of the instances based on
kconfig.
When the driver was made to use DT, it was done in a way that required
both DT and kconfig needing to manually coherently enable the 2nd UART.
This has now been fixed, which it means only DT is used to decide how
many instances are avaliable, and UART_NATIVE_POSIX_PORT_1_ENABLE is
just ignored.

Including:
* Deprecate UART_NATIVE_WAIT_PTS_READY_ENABLE: the options is always on
  now as it has no practical drawbacks.
* Deprecate UART_NATIVE_POSIX_PORT_1_ENABLE: DTS intanciation defines it
  being available now.
* Rename a few functions and in general shorten pseudo-tty/pseudo-
  terminal to PTY instead of PTTY.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

Author: aescolar

boards/native/native_sim/doc/index.rst

@@ -310,10 +310,10 @@ The following peripherals are currently provided with this board:
 **UART/Serial**
    Two optional native UART drivers are available:
 
-   **PTTY driver (UART_NATIVE_POSIX)**
-      With this driver, one or two Zephyr UART devices can be created. These
+   **PTY driver (UART_NATIVE_PTY)**
+      With this driver, Zephyr UART devices can be created. These
       can be connected to the Linux process stdin/stdout or a newly created
-      pseudo-tty. For more information refer to the section `PTTY UART`_.
+      pseudo-tty. For more information refer to the section `PTY UART`_.
 
    **TTY driver (UART_NATIVE_TTY)**
       An UART driver for interacting with host-attached serial port devices
@@ -510,44 +510,46 @@ The following peripherals are currently provided with this board:
 
 .. _native_ptty_uart:
 
-PTTY UART
+PTY UART
 =========
 
-This driver can be configured with :kconfig:option:`CONFIG_UART_NATIVE_POSIX`
-to instantiate up to two UARTs. By default only one UART is enabled.
-With :kconfig:option:`CONFIG_UART_NATIVE_POSIX_PORT_1_ENABLE`
-you can enable the second one.
-
-For the first UART, it can link it to a new
-pseudoterminal (i.e. :file:`/dev/pts{<nbr>}`), or map the UART input and
-output to the executable's ``stdin`` and ``stdout``.
-This is chosen by selecting either
-:kconfig:option:`CONFIG_NATIVE_UART_0_ON_OWN_PTY` or
-:kconfig:option:`CONFIG_NATIVE_UART_0_ON_STDINOUT`
-For interactive use with the :ref:`shell_api`, choose the first (OWN_PTY) option.
-The second (STDINOUT) option can be used with the shell for automated
-testing, such as when piping other processes' output to control it.
-This is because the shell subsystem expects access to a raw terminal,
+This driver is automatically enabled when devicetree contains nodes with the
+``"zephyr,native-pty-uart"`` compatible property and ``okay`` status and
+:kconfig:option:`CONFIG_SERIAL` is set.
+By default one ready UART of this type is setup in DTS, but any number can be enabled as desired.
+
+Normally these UARTs are connected to new pseudoterminals PTYs, i.e. :file:`/dev/pts{<nbr>}`,
+but it is also possible to map one of them to the executable's ``stdin`` and ``stdout``.
+This can be done in two ways, either with the command line option ``--<uart_name>_stdinout``
+(where ``<uart_name>`` is the UART DTS node name), or, for the first PTY UART instance by chosing
+:kconfig:option:`CONFIG_UART_NATIVE_PTY_0_ON_STDINOUT` instead of the default
+:kconfig:option:`CONFIG_UART_NATIVE_PTY_0_ON_OWN_PTY`.
+For interactive use with the :ref:`shell_api`, it is recommended to choose the PTY option.
+The ``STDINOUT`` option can be used for automated testing, such as when piping other processes'
+output to control it. This is because the shell subsystem expects access to a raw terminal,
 which (by default) a normal Linux terminal is not.
 
-When :kconfig:option:`CONFIG_NATIVE_UART_0_ON_OWN_PTY` is chosen, the name of the
-newly created UART pseudo-terminal will be displayed in the console.
-If you want to interact with it manually, you should attach a terminal emulator
-to it. This can be done, for example with the command:
+When a UART is connected to a new PTY, the name of the newly created UART pseudo-terminal will be
+displayed in the console.
+If you want to interact with it manually, you should attach a terminal emulator to it.
+This can be done, for example with the command:
 
 .. code-block:: console
 
-   $ xterm -e screen /dev/<ttyn> &
+   $ xterm -e screen /dev/<ptyn> &
+   # Or if you prefer gnome-terminal:
+   $ gnome-terminal -- screen /dev/<ptyn> &
 
-where :file:`/dev/tty{<n>}` should be replaced with the actual TTY device.
+where :file:`/dev/{<ptyn>}` should be replaced with the actual PTY device.
 
-You may also chose to automatically attach a terminal emulator to the first UART
-by passing the command line option ``-attach_uart`` to the executable.
-The command used for attaching to the new shell can be set with the command line
-option ``-attach_uart_cmd=<"cmd">``. Where the default command is given by
-:kconfig:option:`CONFIG_NATIVE_UART_AUTOATTACH_DEFAULT_CMD`.
-Note that the default command assumes both ``xterm`` and ``screen`` are
-installed in the system.
+You may also chose to automatically attach a terminal emulator to any of these UARTs.
+To automatically attach one to all these UARTs, pass the command line option ``-attach_uart`` to the
+executable. To automatically attach one to a single UART use ``-<uart_name>_attach_uart``
+The command used for attaching to the new shell can be set for all UARTs with the command line
+option ``-attach_uart_cmd=<"cmd">``, or for each individual UART with
+``-<uart_name>_attach_uart_cmd``. Where the default command is given by
+:kconfig:option:`CONFIG_UART_NATIVE_PTY_AUTOATTACH_DEFAULT_CMD`.
+Note that the default command assumes both ``xterm`` and ``screen`` are installed in the system.
 
 This driver only supports poll mode. Interrupt and async mode are not supported.
 Neither runtime configuration or line control are supported.
@@ -713,7 +715,7 @@ host libC (:kconfig:option:`CONFIG_EXTERNAL_LIBC`):
      Logger backend, :ref:`Native backend <nsim_back_logger>`, :kconfig:option:`CONFIG_LOG_BACKEND_NATIVE_POSIX`, All
      Offloaded sockets, :ref:`nsim_per_offloaded_sockets`, :kconfig:option:`CONFIG_NET_NATIVE_OFFLOADED_SOCKETS`, All
      RTC, RTC emul, :kconfig:option:`CONFIG_RTC_EMUL`, All
-     Serial, :ref:`UART native posix/PTTY <native_ptty_uart>`, :kconfig:option:`CONFIG_UART_NATIVE_POSIX`, All
+     Serial, :ref:`UART native PTY <native_ptty_uart>`, :kconfig:option:`CONFIG_UART_NATIVE_PTY`, All
      Serial, :ref:`UART native TTY <native_tty_uart>`, :kconfig:option:`CONFIG_UART_NATIVE_TTY`, All
      SPI, SPI emul, :kconfig:option:`CONFIG_SPI_EMUL`, All
      System tick, Native_posix timer, :kconfig:option:`CONFIG_NATIVE_POSIX_TIMER`, All

boards/native/native_sim/native_sim.dts

@@ -147,16 +147,16 @@
 
 	uart0: uart {
 		status = "okay";
-		compatible = "zephyr,native-posix-uart";
+		compatible = "zephyr,native-pty-uart";
 		/* Dummy current-speed entry to comply with serial
 		 * DTS binding
 		 */
 		current-speed = <0>;
 	};
 
 	uart1: uart_1 {
-		status = "okay";
-		compatible = "zephyr,native-posix-uart";
+		status = "disabled";
+		compatible = "zephyr,native-pty-uart";
 		/* Dummy current-speed entry to comply with serial
 		 * DTS binding
 		 */

doc/connectivity/networking/eth_bridge_native_sim_setup.rst

@@ -58,7 +58,7 @@ Then create a sample and enable Ethernet bridging support. In this example we cr
 
    west build -p -b native_sim -d ../build/echo-server \
       samples/net/sockets/echo_server -- \
-      -DCONFIG_NATIVE_UART_AUTOATTACH_DEFAULT_CMD="\"gnome-terminal -- screen %s\"" \
+      -DCONFIG_UART_NATIVE_PTY_AUTOATTACH_DEFAULT_CMD="\"gnome-terminal -- screen %s\"" \
       -DCONFIG_NET_ETHERNET_BRIDGE=y \
       -DCONFIG_NET_ETHERNET_BRIDGE_SHELL=y \
       -DCONFIG_ETH_NATIVE_TAP_INTERFACE_COUNT=2 \

doc/connectivity/networking/network_monitoring.rst

@@ -117,7 +117,7 @@ In terminal #3, type:
    :zephyr-app: samples/net/capture
    :host-os: unix
    :board: native_sim
-   :gen-args: -DCONFIG_NATIVE_UART_AUTOATTACH_DEFAULT_CMD=\""gnome-terminal -- screen %s"\"
+   :gen-args: -DCONFIG_UART_NATIVE_PTY_AUTOATTACH_DEFAULT_CMD=\""gnome-terminal -- screen %s"\"
    :goals: build
    :compact:
 

drivers/serial/CMakeLists.txt

@@ -103,13 +103,13 @@ if (CONFIG_UART_NRFX_UARTE)
   endif()
 endif()
 
-if(CONFIG_UART_NATIVE_POSIX)
+if(CONFIG_UART_NATIVE_PTY)
   zephyr_library_compile_definitions(NO_POSIX_CHEATS)
-  zephyr_library_sources(uart_native_ptty.c)
+  zephyr_library_sources(uart_native_pty.c)
   if (CONFIG_NATIVE_APPLICATION)
-    zephyr_library_sources(uart_native_ptty_bottom.c)
+    zephyr_library_sources(uart_native_pty_bottom.c)
   else()
-    target_sources(native_simulator INTERFACE uart_native_ptty_bottom.c)
+    target_sources(native_simulator INTERFACE uart_native_pty_bottom.c)
   endif()
 endif()
 

drivers/serial/Kconfig

@@ -191,7 +191,7 @@ rsource "Kconfig.mcux_lpuart"
 rsource "Kconfig.mec5"
 rsource "Kconfig.miv"
 rsource "Kconfig.msp432p4xx"
-rsource "Kconfig.native_posix"
+rsource "Kconfig.native_pty"
 rsource "Kconfig.native_tty"
 rsource "Kconfig.neorv32"
 rsource "Kconfig.npcx"

drivers/serial/Kconfig.native_posix

@@ -0,0 +1,105 @@
+# Copyright (c) 2025, Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+config UART_NATIVE_PTY
+	bool "PTY based UART driver for native_sim"
+	default y
+	depends on (DT_HAS_ZEPHYR_NATIVE_PTY_UART_ENABLED || DT_HAS_ZEPHYR_NATIVE_POSIX_UART_ENABLED)
+	select SERIAL_HAS_DRIVER
+	help
+	  This enables a PTY based UART driver for the POSIX ARCH with up to 2 UARTs.
+	  For the first UART port, the driver can be configured
+	  to either connect to the terminal from which the executable was run, or into
+	  one dedicated pseudoterminal for that UART.
+
+config UART_NATIVE_POSIX
+	bool "UART driver for native_sim (deprecated)"
+	select SERIAL_HAS_DRIVER
+	select DEPRECATED
+	select UART_NATIVE_PTY
+	help
+	  Deprecated option, use UART_NATIVE_PTY instead
+
+if (UART_NATIVE_PTY || UART_NATIVE_POSIX)
+
+choice UART_NATIVE_PTY_0
+	prompt "Native PTY Port 0 connection"
+	default UART_NATIVE_PTY_0_ON_STDINOUT if NATIVE_UART_0_ON_STDINOUT
+	default UART_NATIVE_PTY_0_ON_OWN_PTY
+
+config UART_NATIVE_PTY_0_ON_OWN_PTY
+	bool "Connect the first PTY UART to its own pseudo terminal"
+	help
+	  Connect this UART to its own pseudoterminal. This is the preferred
+	  option for users who want to use Zephyr's shell.
+	  Moreover this option does not conflict with any other native
+	  backend which may use the invoking shell standard input/output.
+	  Note it can be overridden from command line
+
+config UART_NATIVE_PTY_0_ON_STDINOUT
+	bool "Connect the first PTY UART to the invoking shell stdin/stdout"
+	help
+	  Connect this UART to the stdin & stdout of the calling shell/terminal
+	  which invoked the native executable. This is good enough for
+	  automated testing, or when feeding from a file/pipe.
+	  Note that other, non UART messages, will also be printed to the
+	  terminal.
+	  It is strongly discouraged to try to use this option with the new
+	  shell interactively, as the default terminal configuration is NOT
+	  appropriate for interactive use.
+
+endchoice
+
+choice NATIVE_UART_0
+	prompt "Native UART Port 0 connection (deprecated)"
+	default NATIVE_UART_0_ON_OWN_PTY
+
+config NATIVE_UART_0_ON_OWN_PTY
+	bool "Connect the UART to its own pseudo terminal (deprecated)"
+	help
+	  Deprecated, use UART_NATIVE_PTY_0_ON_OWN_PTY instead.
+
+config NATIVE_UART_0_ON_STDINOUT
+	bool "Connect the UART to the invoking shell stdin/stdout (deprecated)"
+	select DEPRECATED
+	help
+	  Deprecated, use UART_NATIVE_PTY_0_ON_STDINOUT instead.
+
+endchoice
+
+config UART_NATIVE_WAIT_PTS_READY_ENABLE
+	bool "Support waiting for pseudo terminal client readiness (deprecated)"
+	select DEPRECATED
+	help
+	  This option is deprecated and does not do anything anymore. (The command line
+	  option --wait_uart is always available).
+
+config UART_NATIVE_POSIX_PORT_1_ENABLE
+	bool "Second UART port (deprecated)"
+	select DEPRECATED
+	help
+	  This option does not do anything anymore. Use DTS to instantiate as many
+	  "zephyr,native-pty-uart" compatible nodes as you want.
+
+config UART_NATIVE_PTY_AUTOATTACH_DEFAULT_CMD
+	string "Default command to attach a PTY UART to a new terminal"
+	default NATIVE_UART_AUTOATTACH_DEFAULT_CMD
+	help
+	  If the native executable is called with the --attach_uart
+	  command line option, this will be the default command which will be
+	  run to attach a new terminal to the 1st UART.
+	  Note that this command must have one, and only one, '%s' as
+	  placeholder for the pseudoterminal device name (e.g. /dev/pts/35)
+	  This is only applicable if the UART_0 is configured to use its own
+	  PTY with NATIVE_UART_0_ON_OWN_PTY.
+	  The 2nd UART will not be affected by this option.
+	  If you are using GNOME, then you can use this command string
+	  'gnome-terminal -- screen %s'
+
+config NATIVE_UART_AUTOATTACH_DEFAULT_CMD
+	string "Default command to attach the UART to a new terminal (deprecated)"
+	default "xterm -e screen %s &"
+	help
+	  Deprecated. Use UART_NATIVE_PTY_AUTOATTACH_DEFAULT_CMD instead
+
+endif # UART_NATIVE_PTY || UART_NATIVE_POSIX