Re: [PATCH v5] i2c: virtio: add a virtio i2c frontend driver

Jason Wang
2021-03-02T08:24:35Z

On 2021/3/2 1:16 下午, Viresh Kumar wrote:
> On 02-03-21, 13:06, Jie Deng wrote:
>> Yeah. Actually, the backend only needs "struct virtio_i2c_out_hdr out_hdr"
>> and "struct virtio_i2c_in_hdr in_hdr" for communication. So we only need to
>> keep
>> the first two in uapi and move "struct virtio_i2c_req" into the driver.
>>
>> But Jason wanted to include "struct virtio_i2c_req" in uapi. He explained in
>> this link
>> https://lists.linuxfoundation.org/pipermail/virtualization/2020-October/050222.html.
>> Do you agree with that explanation ?
> I am not sure I understood his reasoning well, but it doesn't make any
> sense to keep this in uapi header if this is never going to get
> transferred over the wire.

I think I was wrong. It should be sufficient have in_hdr and out_hdr in
uAPI.

Thanks

>
> Moreover, the struct virtio_i2c_req in spec is misleading to me and
> rather creates unnecessary confusion. There is no structure like this
> which ever get passed here, but rather there are multiple vq
> transactions which take place, one with just the out header, then one
> with buffer and finally one with in header.
>
> I am not sure what's the right way of documenting it or if this is a
> standard virtio world follows.
>