[U-Boot] [PATCH] dm: gpio: handle GPIO_ACTIVE_LOW flag in DT

Eric Nelson
2016-03-31T20:41:04Z

Hi Peng,

On 03/28/2016 09:57 PM, Peng Fan wrote:
> Hi Eric,
>
> On Fri, Mar 25, 2016 at 01:12:11PM -0700, Eric Nelson wrote:
>> Device tree parsing of GPIO nodes is currently ignoring flags.
>>
>> Add support for GPIO_ACTIVE_LOW by checking for the presence
>> of the flag and setting the desc->flags field to the driver
>> model constant GPIOD_ACTIVE_LOW.
>
> You may need to try this: https://patchwork.ozlabs.org/patch/597363/
>
Thanks for pointing this out.

This patch also works, but it has me confused.

How/why is parsing the ACTIVE_LOW flag specific to MXC?

This is a general-purpose flag in the kernel, not something machine-
specific.

It also appears that there are a bunch of other copies
of this same bit of code in the various mach_xlate() routines:

desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;

If it's done in gpio-uclass, this isn't needed and xlate can
be removed from mxc-gpio and quite a few other architectures.

Please advise,

Eric