Re: [PATCH] ARM: mvebu: switch to using gpiod API in pm-board code

Andrew Lunn
2022-11-16T02:03:16Z

On Tue, Nov 15, 2022 at 05:40:35PM -0800, Dmitry Torokhov wrote:
> On Wed, Nov 16, 2022 at 02:10:29AM +0100, Andrew Lunn wrote:
> > > - ret = gpio_direction_output(pic_gpios[i], 0);
> > > - if (ret < 0) {
> > > - gpio_free(pic_gpios[i]);
> > > + pic_gpios[i] = fwnode_gpiod_get_index(of_fwnode_handle(np),
> > > + "ctrl", i, GPIOD_OUT_HIGH,
> > > + name);
> >
> > The old code passes value=0 to gpio_direction_output(). For
> > fwnode_gpiod_get_index() you pass GPIOD_OUT_HIGH. Is this correct?
>
> Yes, gpiod API works on logical states, whereas old gpio API used signal
> levels. In arch/arm/boot/dts/armada-xp-gp.dts ctrl-gpios are described
> as "active low":
>
> cpus {
> pm_pic {
> ctrl-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>,
> <&gpio0 17 GPIO_ACTIVE_LOW>,
> <&gpio0 18 GPIO_ACTIVE_LOW>;
> };
> };
>
> so gpiolib will translate GPIOD_OUT_HIGH to 0 when setting final state
> of the pin.

Ah, yes. I knew that once, but it has gotten forgotten.

Thanks for the explanation and reminder.

Andrew