tty slave device support - version 3.

Hi again,
here is version 3 of support for tty-slaves.

This version introduces a new bus-type for tty-slaves, and causes a tty-slave device to appear in /sys/devices between the uart and the tty.
It effectively intercepts and calls from the tty to the uart (i.e. any tty_operations) and applies extra functionality at that point.

Currently the only driver intercepts open and close. It powers on the device on open, and powers off at last-close.

Power can be controlled by a regulator or by toggling a GPIO.

I think I've incorporated most of the feed back I received from previous versions, but if I missed something - I apologize. If this approach is structurally acceptable then I can fix up all the smaller issues.

Thanks for your review,
NeilBrown

---

NeilBrown (3):
TTY: use class_find_device to find port in uart_suspend/resume.
TTY: add support for tty_slave devices.
tty/slaves: add a driver to power on/off UART attached devices.

 .../bindings/tty_slave/wi2wi,w2cbw003.txt          |   19 +
 .../bindings/tty_slave/wi2wi,w2sg0004.txt          |   37 +
 .../devicetree/bindings/vendor-prefixes.txt        |    1 
 drivers/tty/Kconfig                                |    1 
 drivers/tty/Makefile                               |    1 
 drivers/tty/serial/serial_core.c                   |   21 -
 drivers/tty/slave/Kconfig                          |   21 +
 drivers/tty/slave/Makefile                         |    4 
 drivers/tty/slave/serial-power-manager.c           |  510 ++++++++++++++++++++
 drivers/tty/slave/tty_slave_core.c                 |  136 +++++
 drivers/tty/tty_io.c                               |   60 ++
 include/linux/tty.h                                |    2 
 include/linux/tty_slave.h                          |   26 +
 13 files changed, 813 insertions(+), 26 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/tty_slave/wi2wi,w2cbw003.txt
 create mode 100644 Documentation/devicetree/bindings/tty_slave/wi2wi,w2sg0004.txt
 create mode 100644 drivers/tty/slave/Kconfig
 create mode 100644 drivers/tty/slave/Makefile
 create mode 100644 drivers/tty/slave/serial-power-manager.c
 create mode 100644 drivers/tty/slave/tty_slave_core.c
 create mode 100644 include/linux/tty_slave.h

--
Signature