On Fri, 2017-01-06 at 10:26 -0600, Rob Herring wrote:

Here goes another attempt at a serial device bus (aka uart slaves, tty
slaves, etc.).

After some discussions with Dmitry at LPC, I decided to move away from
extending serio and moved back to making a new bus type instead. He
didn't
think using serio was a good fit, and serio has a number of
peculiarities
in regards to sysfs and it's driver model. I don't think we want to
inherit
those for serial slave devices.

This version sits on top of tty_port rather than uart_port as Alan
requested. Once I created a struct tty rather than moving everything
needed to tty_port, it became a lot easier and less invasive to the
tty
core code.

I have hacked up versions of the BT ldisc and TI ST drivers moved over
to
use the serdev bus. I have BT working on the HiKey board which has TI
BT.
With the serdev bus support, it eliminates the need for the TI
userspace
UIM daemon.

This series and the mentioned drivers can be found here[1].

For patches 1-4:
Reviewed-by: Andy Shevchenko <andriy.shevchenko-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

Regarding to naming. Why can't we just name bus "serial"? If you are
worrying about folder name under drivers/tty, I can propose at lease
couple of options serialdev, serialbus.

Rob

[1] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git
serial-bus-v2

Alan Cox (1):
  tty_port: allow a port to be opened with a tty that has no file
handle

Rob Herring (8):
  tty: move the non-file related parts of tty_release to new
    tty_release_struct
  tty_port: make tty_port_register_device wrap
    tty_port_register_device_attr
  tty: constify tty_ldisc_receive_buf buffer pointer
  tty_port: Add port client functions
  dt/bindings: Add a serial/UART attached device binding
  serdev: Introduce new bus for serial attached devices
  serdev: add a tty port controller driver
  tty_port: register tty ports with serdev bus

 .../devicetree/bindings/serial/slave-device.txt    |  34 ++
 MAINTAINERS                                        |   8 +
 drivers/char/Kconfig                               |   1 +
 drivers/tty/Makefile                               |   1 +
 drivers/tty/serdev/Kconfig                         |  16 +
 drivers/tty/serdev/Makefile                        |   5 +
 drivers/tty/serdev/core.c                          | 388
+++++++++++++++++++++
 drivers/tty/serdev/serdev-ttyport.c                | 244
+++++++++++++
 drivers/tty/tty_buffer.c                           |  19 +-
 drivers/tty/tty_io.c                               |  44 ++-
 drivers/tty/tty_port.c                             |  60 +++-
 include/linux/serdev.h                             | 227 ++++++++++++
 include/linux/tty.h                                |  12 +-
 13 files changed, 1017 insertions(+), 42 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/serial/slave-
device.txt
 create mode 100644 drivers/tty/serdev/Kconfig
 create mode 100644 drivers/tty/serdev/Makefile
 create mode 100644 drivers/tty/serdev/core.c
 create mode 100644 drivers/tty/serdev/serdev-ttyport.c
 create mode 100644 include/linux/serdev.h

-- 
Andy Shevchenko [off-list ref]
Intel Finland Oy