> Date: Sun, 27 Mar 2016 20:29:29 -0700
> From: Philip Guenther <[email protected]>
>
> On Sun, Mar 27, 2016 at 12:28 PM, Mark Kettenis <[email protected]>
> wrote:
> > The diff below is a first stab at adding support for GPIOs as defined
> > in ACPI 5.0. The primary target for this new ACPI feature is hardware
> > reduced platforms like those based on Intel's Bay Trail SoC. The diff
> > adds a bytgpio(4) driver for the hardware found on that SoC. This
> > driver registers itself with the acpi framework by setting the struct
> > acpi_gpio pointer on the AML node for the device. Then this gets used
> > by the acpi sdhc(4) frontend to use the appropriate gpio as the card
> > detect signal. This makes it possible to detectwhether a card is
> > inserted when the kernel boots. Support for GPIO-based interrupts is
> > still missing, so hotplugging SD cards doesn't work yet.
> >
> > There are some debug printfs here that will disappear eventually.
> >
> > ok?
>
> Not really specific to this driver, but should we be using letoh16()
> and similar when accessing the fields like pin_off? We do so in a few
> acpi drivers, but many do not and I'm not aware of any big-endian
> archs that are looking to use ACPI ("here, have another albatross!").
In theory there could be future big-endian ARM systems with ACPI
firmware. Let's worry about those if we ever see one that we want to
support.
> > +/*
> > + * The pads for the pins are randomly ordered.
> > + */
> > +
> > +const int byt_score_pins[] = {
>
> These values from some Intel doc?
I took them from the Linux driver. It is possible to figure out the
mapping from the Intel docs.
> ...
> > + switch (uid) {
> > + case 1:
> > + sc->sc_pins = byt_score_pins;
> > + sc->sc_npins = nitems(byt_score_pins);
>
> ok...
>
> > + break;
> > + case 2:
> > + sc->sc_pins = byt_score_pins;
> > + sc->sc_npins = nitems(byt_ncore_pins);
>
> Uh, mismatch here and on the next. Shouldn't sc_pins be set to
> byt_ncore_pins and byt_sus_pins?
Yes. Fixed.
> > + break;
> > + case 3:
> > + sc->sc_pins = byt_score_pins;
> > + sc->sc_npins = nitems(byt_sus_pins);
Thanks,
Mark
