[PATCH v4 0/2] Add remote I2C device to support external I2C device

[Shengtan Mao]

This patch implements the remote I2C device.  The remote I2C device allows an
external I2C device to communicate with the I2C controller in QEMU through the
remote I2C protocol.  Users no longer have to directly modify QEMU to add new
I2C devices and can instead implement the emulated device externally and
connect it to the remote I2C device.

Previous work by Wolfram Sang
(https://git.kernel.org/pub/scm/virt/qemu/wsa/qemu.git/commit/?h=i2c-passthrough)
was referenced.  It shares the similar idea of redirecting the actual I2C device
functionalities, but Sang focuses on physical devices, and we focus on emulated 
devices.
The work by Sang mainly utilizes file descriptors while ours utilizes character
devices, which offers better support for emulated devices. The work by Sang is
not meant to offer full I2C device support; it only implements the receive
functionality.  Our work implements full support for I2C devices: send, recv,
and event (match_and_add is not applicable for external devices).

v1 -> v2
    fixed terminology errors in the description comments.
v2 -> v3
    corrected patch set emailing errors.
v3 -> v4
    added remote I2C protocol description in docs/specs

Shengtan Mao (2):
  hw/i2c: add remote I2C device
  docs/specs: add remote i2c docs

 docs/specs/index.rst          |   1 +
 docs/specs/remote-i2c.rst     |  51 ++++++++
 hw/arm/Kconfig                |   1 +
 hw/i2c/Kconfig                |   4 +
 hw/i2c/meson.build            |   1 +
 hw/i2c/remote-i2c.c           | 117 ++++++++++++++++++
 tests/qtest/meson.build       |   1 +
 tests/qtest/remote-i2c-test.c | 216 ++++++++++++++++++++++++++++++++++
 8 files changed, 392 insertions(+)
 create mode 100644 docs/specs/remote-i2c.rst
 create mode 100644 hw/i2c/remote-i2c.c
 create mode 100644 tests/qtest/remote-i2c-test.c

-- 
2.32.0.605.g8dce9f2422-goog