[PATCH] backlight: lms283gf05: Convert to GPIO descriptors

[Linus Walleij]

On Wed, Apr 29, 2020 at 1:33 PM Daniel Thompson
<daniel.thompson at linaro.org> wrote:
> On Wed, Apr 29, 2020 at 10:26:31AM +0200, Linus Walleij wrote:

> > -     if (pdata != NULL) {
> > -             ret = devm_gpio_request_one(&spi->dev, pdata->reset_gpio,
> > -                             GPIOF_DIR_OUT | (!pdata->reset_inverted ?
> > -                             GPIOF_INIT_HIGH : GPIOF_INIT_LOW),
> > -                             "LMS283GF05 RESET");
> > -             if (ret)
> > -                     return ret;
> > -     }
> > +     st->reset = gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_HIGH);
>
> Isn't this a change of behaviour w.r.t. to the initial state of the pin?

Yeah you're right. The original author intended reset to be
de-asserted here so it should be GPIOD_OUT_LOW.

> To be honest I suspect it is harmless because we launch into the reset
> sequence shortly after anyway. More that that I think I prefer it this
> way since it is better aligned with the behaviour of
> lms283gf05_power_set().
>
> However if it is an intentional change of behaviour then it would be
> good to spell that out in the description for the benefit of future
> archaeologists.

Hm I'd rather not change semantics actually, you never know.
I'll switch it back. If we decide to change it I'd use GPIOD_ASIS
and not touch the hardware here.

Yours,
Linus Walleij