On 2020/9/3 14:12, Jason Wang wrote:

On 2020/9/3 下午1:34, Jie Deng wrote:

quoted

Add an I2C bus driver for virtio para-virtualization.

The controller can be emulated by the backend driver in
any device model software by following the virtio protocol.

This driver communicates with the backend driver through a
virtio I2C message structure which includes following parts:

- Header: i2c_msg addr, flags, len.
- Data buffer: the pointer to the i2c msg data.
- Status: the processing result from the backend.

People may implement different backend drivers to emulate
different controllers according to their needs. A backend
example can be found in the device model of the open source
project ACRN. For more information, please refer to
https://projectacrn.org.

May I know the reason why don't you use i2c or virtio directly?

We don't want to add virtio drivers for every I2C devices in the guests.
This bus driver is designed to provide a way to flexibly expose the 
physical
I2C slave devices to the guest without adding or changing the drivers of 
the
I2C slave devices in the guest OS.

quoted

The virtio device ID 34 is used for this I2C adpter since IDs
before 34 have been reserved by other virtio devices.

Is there a link to the spec patch?

Thanks

I haven't submitted the patch to reserve the ID in spec yet.
I write the ID here because I want to see your opinions first.

Thanks


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