Re: [PATCH 2/5] gpio: davinci: Use dev name for label and automatic base selection

David Lechner
2018-09-10T17:03:28Z

On 09/10/2018 02:37 AM, Sekhar Nori wrote:
> On Monday 10 September 2018 12:55 PM, Linus Walleij wrote:
>> On Sat, Sep 8, 2018 at 9:41 PM Grygorii Strashko
>> <grygorii.strashko@ti.com> wrote:
>>> On 09/06/2018 09:16 AM, Keerthy wrote:
>>
>>>> Okay now its numbered differently:
>>>>
>>>> cat /sys/class/gpio/gpiochip340/ngpio
>>>> 144
>>>>
>>>> cat /sys/class/gpio/gpiochip272/ngpio
>>>> 68
>> (...)
>>
>> So:
>>
>>>>> Are there applications that rely on the sysfs ABI on DaVinci?
>>>>>
>>>>> In that case base needs to be prerseved.
>>>
>>> Not only base, but label also - /sys/class/gpio/gpiochip0/label, as this is
>>> the way to find proper GPIO chip in sysfs using legacy GPIO ABI.
>>>
>>> Linus, this platform is old and most of the users do not use new ABI (chardev),
>>> so we could try change this, but need to be prepared for regressions reports.
>>
>> So what I'm trying to ask you guys is if there are applications that you
>> are aware of that use the old ABI, and who will upgrade their
>> kernels and be upset.
>>
>> We must not break userspace, but as you know if a tree falls in the
>> forest and nobody is there to hear it, it doesn't make a sound.
>>
>> If you're not aware of any such applications I guess we should try
>> changing this.
>
> Personally I am not really aware of any application which relies on the
> ABI. I may have some scripts, but I can adjust them. I am also copying
> some frequent users of DaVinci in mainline for any comments from them.
>
> Thanks,
> Sekhar
>

It won't break anything that I am aware of.