Re: [PATCH v2 2/4] da850-evm: add UI Expander pushbuttons

[Kevin Hilman <khilman@deeprootsystems.com>]

"Nori, Sekhar" <nsekhar@ti.com> writes:

> Hi Ben,
>
> On Mon, Nov 22, 2010 at 19:20:48, Ben Gardiner wrote:
>> On Mon, Nov 22, 2010 at 6:49 AM, Nori, Sekhar <nsekhar@ti.com> wrote:
>> > On Fri, Nov 19, 2010 at 21:08:10, Ben Gardiner wrote:
>> >> [...]
>> >> By setting INPUT_POLLDEV default for the da850-evm users will get
>> >> functioning pushbuttons and switches with the default config but they
>> >> will be able to disable INPUT_POLLDEV or gpio-keys drivers in their
>> >> defconfig at their convenience.
>> >
>> > I guess we could also just modify the defconfig to switch on
>> > INPUT_POLLDEV? Since only gpio-keys functionality is affected
>> > by not enabling the correct options in kernel, it should be OK.
>>
>> Yes -- only gpio-keys is affected but enabling the option does
>> introduce an additional .o file:
>>
>> drivers/input/Makefile:obj-$(CONFIG_INPUT_POLLDEV)      += input-polldev.o
>>
>> I agree that in its current state a user couls inadvertently disable
>> the gpio-keys support on da850-evm simply by disabling INPUT_POLLDEV
>> -- which is less than Ideal. How about I replace the current changes
>> to arch/arm/mach-davinci/Kconfig with:
>>
>> config KEYBOARD_GPIO
>>         default MACH_DAVINCI_DA850_EVM
>>         select INPUT_POLLDEV
>>
>> So 1) gpio-keys functionality is default for the da850evm and 2)
>> whenever gpio-keys is enabled so is INPUT_POLLDEV.
>
> This looks better than what was posted earlier, but I am not
> sure if platforms should influence driver configuration this
> way.

Agreed.  In general, we should not have machine/platform specific
conditionals in generic Kconfigs.   Generally, this should be handled in
machine/platform specific Kconfigs.

Kevin


> I guess I am just afraid that this makes a precedent for
> many driver config symbols to get replicated in the platform
> Kconfig files.
>
> Lets see if others have an opinion on this.
>
> Thanks,
> Sekhar