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Subject: Re: [PATCH] i2c: virtio: add a virtio i2c frontend driver
To:     Jie Deng <jie.deng@intel.com>, linux-i2c@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
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        jdelvare@suse.de, Sergey.Semin@baikalelectronics.ru,
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        tali.perry1@gmail.com, bjorn.andersson@linaro.org,
        shuo.a.liu@intel.com, conghui.chen@intel.com, yu1.wang@intel.com
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 <c9be298b-c51b-f7f3-994b-b7bd9ae53b99@intel.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <f89142e6-a92d-b417-5e1c-bbe813636023@redhat.com>
Date:   Wed, 9 Sep 2020 16:54:36 +0800
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On 2020/9/8 上午9:40, Jie Deng wrote:
>
>
> On 2020/9/7 13:40, Jason Wang wrote:
>>
>>>
>>>
>>>>
>>>>>
>>>>> +struct virtio_i2c_msg {
>>>>> +    struct virtio_i2c_hdr hdr;
>>>>> +    char *buf;
>>>>> +    u8 status;
>>>>
>>>>
>>>> Any reason for separating status out of virtio_i2c_hdr?
>>>>
>>> The status is not from i2c_msg. 
>>
>>
>> You meant ic2_hdr? You embed status in virtio_i2c_msg anyway.
>>
>>
> The "i2c_msg" structure defined in i2c.h.
>
>>> So I put it out of virtio_i2c_hdr.
>>
>>
>> Something like status or response is pretty common in virtio request 
>> (e.g net or scsi), if no special reason, it's better to keep it in 
>> the hdr.
>>
> Mainly based on IN or OUT.
>
> The addr, flags and len are from "i2c_msg". They are put in one 
> structure as an OUT**scatterlist.
> The buf can be an OUT**or an IN scatterlist depending on write or read.
> The status is a result from the backend  which is defined as an IN 
> scatterlis. 


Ok. I get this.

Thanks