Re: [PATCH V2] virtio: i2c: Allow zero-length transactions

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Sep 01, 2021 at 11:52:31AM +0530, Viresh Kumar wrote:
> On 31-08-21, 20:03, Michael S. Tsirkin wrote:
> > But if you are doing it like this, then I think we should
> > have conformance clauses that require that the flag
> > is consistent with the buffer.
> 
> Something like this will work ?
> 
> diff --git a/virtio-i2c.tex b/virtio-i2c.tex
> index ae344b2bc822..c7335372a8bb 100644
> --- a/virtio-i2c.tex
> +++ b/virtio-i2c.tex
> @@ -145,6 +145,12 @@ \subsubsection{Device Operation: Operation Status}\label{sec:Device Types / I2C
>  A driver MUST NOT use \field{buf}, for a read request, if the final
>  \field{status} returned from the device is VIRTIO_I2C_MSG_ERR.
> 
> +A driver MUST set the \field{VIRTIO_I2C_FLAGS_M_RD} flag for a read operation,
> +where the buffer is write-only for the device.
> +
> +A driver MUST NOT set the \field{VIRTIO_I2C_FLAGS_M_RD} flag for a write
> +operation, where the buffer is read-only for the device.
> +
>  A driver MUST queue the requests in order if multiple requests are going to
>  be sent at a time.
> 
> -- 
> viresh

Something like this, yes.

-- 
MST