[RFC v2 dev-5.1 4/5] i2c: aspeed: add buffer mode transfer support

[Jae Hyun Yoo]

Hi Joel,

On 7/17/2019 10:58 PM, Joel Stanley wrote:
> Hey Jae,
> 
> On Tue, 2 Jul 2019 at 16:05, Jae Hyun Yoo <jae.hyun.yoo at linux.intel.com> wrote:
>>> Do you want we to merge this series into the openbmc tree for further testing?
>>
>> Yes please. It would be good if it gets tested on more various platforms
>> before upstreaming it.
> 
> I did this and hit some issues.
> 
> The first one is that we don't support this with the qemu model yet
> and so kernel crashes when probing i2c. This is bad, as we gate
> commits to the openbmc yocto tree on them passing a qemu boot test.

I see. Actually, it's one of reasons why I submit this series as an RFC
with CC'ing Cedric. It should be resolved before upstreaming it to linux
tree.

> Secondly, the changes you have made to the driver are incompatible
> with the old device tree. I thought I could revert the device tree
> change in order to get the old behavior, but the driver fails to
> probe. In general we strive to make kernel changes compatible with old
> versions of the device tree. I think that can be achieved here with
> some thought.

Okay. I'll change the resource getting logic using index instead of
'reg-names' then this driver could be probed even with an old device
tree.

> Cedric will try to resolve the qemu issue. If you could create a
> version of the patch that makes the driver compatible with the old
> device tree that would be appreciated.

Thanks a lot Joel and Cedric. I'll submit a new spin soon after adding
the device tree compatibility issue fix. Please update me the qemu side
resolving status.

Regards,
Jae

> Cheers,
> 
> Joel
>