Re: [PATCH v2 1/2] gpio: Add driver for Zynq GPIO controller

From: Linus Walleij
Date: Tue Jul 08 2014 - 05:28:10 EST

On Mon, Jul 7, 2014 at 5:23 PM, Baruch Siach <baruch@xxxxxxxxxx> wrote:
> On Mon, Jul 07, 2014 at 04:51:56PM +0200, Linus Walleij wrote:

>> This needs someone to step in and provide a replacement, my preferred
>> mechanism would be a /dev/gpiochip0/... hierarchy using char devices.
> I really like the ability to control GPIOs from shell, both interactively and
> scripted. I find it useful for quick hardware level debugging,

I would be happy to carry it in the unstable-ABI debugfs for sure.
It's the supported ABI that bothers me.

> and for boot
> time scripting (mainly in initramfs).

What is the usecase here?

> Do you intend to preserve this
> capability in the future? Will I need a special utility (or Busybox applet) to
> do this with char device ioctl?

It is ABI so we have to preserve it. But sometimes people come with
new zuper-complex userspace usecases and want to add this or
that crazy ABI to do stuff in userspace that the kernel can do better.
And all that I intend to just NACK.

Linus Walleij
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