[PATCH] RFC: let gpiod_get_optional et all return NULL when GPIOLIB is not enabled

Linus Walleij linus.walleij at linaro.org
Fri Mar 6 00:26:26 PST 2015


On Thu, Feb 12, 2015 at 10:03 AM, Uwe Kleine-König
<u.kleine-koenig at pengutronix.de> wrote:

> I wonder if gpiod_get_optional et all should be changed to return NULL
> instead.

This is actually the norm in most subsystems returning cookie
pointers, clk, regulator, pinctrl... a NULL pointer is a functional
noop. But normally then NULL is returned from all stubs, not
just optional.

Alexandre, what do you say?

> The obvious downside is that if the device tree specifies a
> reset-gpio and the kernel just fails to use it because there is some
> code missing, this should better be an error. (The adau1977 code has
> this problem already know, but when changing devm_gpiod_get_optional all
> callers are affected.)

Device Tree-specific problems is not something we design
subsystems for, we try to just accomodate them. I'm not
sure I fully understand what you mean here.

Yours,
Linus Walleij



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