Re: [PATCH] HISI LPC: Add Kconfig MFD_CORE dependency

[John Garry <john.garry@huawei.com>]

On 19/04/2018 14:29, Arnd Bergmann wrote:
> On Thu, Apr 19, 2018 at 3:08 PM, John Garry <john.garry@huawei.com> wrote:
>> On 19/04/2018 13:00, Arnd Bergmann wrote:
>>>
>>> On Thu, Apr 19, 2018 at 1:55 PM, John Garry <john.garry@huawei.com> wrote:
>>>>
>>>> For ACPI support of the HiSilicon LPC driver we depend
>>>> on MFD_CORE config.
>>>>
>>>> Currently the HiSi LPC Kconfig entry does not define this
>>>> dependency, so add it.
>>>>
>>>> Fixes: e0aa1563f894 ("HISI LPC: Add ACPI support")
>>>> Reported-and-tested-by: Tan Xiaojun <tanxiaojun@huawei.com>
>>>> Signed-off-by: John Garry <john.garry@huawei.com>
>>>
>>>
>>> Can you explain the specific dependency? Normally MFD_CORE gets
>>> selected by an MFD driver but not other drivers.
>>>
>>
>> For each device on the LPC bus we create an MFD.
>>
>> The reason we do this is that we need to set the resources of the derived
>> MFD, as we should not modify the original ACPI device created in ACPI scan.
>> Details are in the log for e0aa1563f894.
>>
>> Shall I update commit message updated with this info? Or were you just
>> interested in the motivation for using MFD?
>
> I think it would be good to update the description. I had missed the part
> where an LPC device becomes a platform_device through an mfd_cell
> rather than becoming a device with bus_type=&isa_bus_type as I think
> was the case in earlier versions of your patch series.
>

OK, fine. FYI, this was originally discussed here: 
https://lkml.org/lkml/2017/6/13/602

BTW, as for merging patches for this driver, it would seem the right 
place for it to go through arm/soc tree (obviously depending on 
dependencies). Since xuwei is away this week, could you kindly pick up 
v2 for fixes?

Thanks,
John


>      Arnd
>
> .
>