tree 1bd2803a26323aed1ac5e67cfe63956f2349a1d9
parent 311695c35e32d33a4182e44ea67f78237c98d1b0
author Mike Voydanoff <voydanoff@google.com> 1520865188 -0700
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1521076848 +0000

[ddk][serial] Move serial protocol support out of platform bus driver

Instead of implementing UARTs as platform device resources in platform bus,
We now have a generic serial driver that implements ZX_PROTOCOL_SERIAL
on top of the lower level ZX_PROTOCOL_SERIAL_IMPL protocol.
This allows the possibility of using the generic seral protocol support
on x86 as well as SOC based platforms.

In order to make this work, we add some new generic device properties to our binding rules:
BIND_DEVICE_VID, BIND_DEVICE_PID and BIND_DEVICE_CLASS.
In this CL we use BIND_DEVICE_CLASS to specify the serial port type
(for example Bluetooth HCI versus generic serial port)
and BIND_DEVICE_VID and BIND_DEVICE_PID to specify which Bluetooth firmware
to use in the case of HCI.

We also simplify the serial protocols by eliminating port numbers from the APIs.
Now serial drivers support only one serial port each, so we now have separate
driver instances per serial port.
This is necessary to maintain the flexibility of running serial port clients
in separate devhosts after decoupling from the platform bus.

Change-Id: Ife2c611a1340ec99440595e45d79bdcf63979644