tty: add SPDX identifiers to Kconfig and Makefiles

There were a few Kconfig and Makefiles under drivers/tty/ that were
missing a SPDX identifier. Fix that up so that automated tools can
properly classify all kernel source files.

Cc: Jiri Slaby <jslaby@suse.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serdev: enable TTY port controller support by default

Amend the Serial device bus Kconfig entries to clarify that you most
likely also want to enable TTY port controller support, and make
SERIAL_DEV_CTRL_TTYPORT default to Y (when bus support is enabled).

Note that the TTY port controller is currently the only in-kernel
serdev controller implementation.

Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serdev: add a tty port controller driver

Add a serdev controller driver for tty ports.

The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

serdev: Introduce new bus for serial attached devices

The serdev bus is designed for devices such as Bluetooth, WiFi, GPS
and NFC connected to UARTs on host processors. Tradionally these have
been handled with tty line disciplines, rfkill, and userspace glue such
as hciattach. This approach has many drawbacks since it doesn't fit
into the Linux driver model. Handling of sideband signals, power control
and firmware loading are the main issues.

This creates a serdev bus with controllers (i.e. host serial ports) and
attached devices. Typically, these are point to point connections, but
some devices have muxing protocols or a h/w mux is conceivable. Any
muxing is not yet supported with the serdev bus.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-By: Sebastian Reichel <sre@kernel.org>
Tested-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>