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Subject: Re: [PATCH] i2c: virtio: add a virtio i2c frontend driver
To:     "Michael S. Tsirkin" <mst@redhat.com>
Cc:     linux-i2c@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
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References: <0efc2605c8c06b4b1bf68cbad5536c4a900dc019.1599110284.git.jie.deng@intel.com>
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From:   Jie Deng <jie.deng@intel.com>
Message-ID: <158c9601-d38c-47b4-9493-43fd89a85398@intel.com>
Date:   Fri, 4 Sep 2020 13:28:59 +0800
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On 2020/9/3 17:58, Michael S. Tsirkin wrote:
> On Thu, Sep 03, 2020 at 01:34:45PM +0800, Jie Deng wrote:
>> 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.
>>
>> The virtio device ID 34 is used for this I2C adpter since IDs
>> before 34 have been reserved by other virtio devices.
> Please reserve the ID with the virtio tc so no one conflicts.
>
Sure. I will send a patch to request the ID.


>
> +
> +/**
> + * struct virtio_i2c_hdr - the virtio I2C message header structure
> + * @addr: i2c_msg addr, the slave address
> + * @flags: i2c_msg flags
> + * @len: i2c_msg len
> + */
> +struct virtio_i2c_hdr {
> +	__virtio16 addr;
> +	__virtio16 flags;
> +	__virtio16 len;
> +} __packed;
> virtio16 is for legacy devices, modern ones should be __le.
> and  we don't really need to pack it I think.

Right. I will fix these. Thanks.