Re: How to use an ACPI declared GPIO in a userspace ...

Andy Shevchenko
2020-09-30T15:55:31Z

On Wed, Sep 30, 2020 at 6:39 PM Flavio Suligoi <f.suligoi@asem.it> wrote:
> > I guess you simply didn't get. The "gpio-line-names" property of GPIO
> > *controller* (provider!) and you are trying to do something with the
> > *consumer*
> > if I got it right.
> >
> > And of course GPIO line, which has name, has no difference in use from
> > another
> > w/o name assigned. You will need to request it by *consumer* either in
> > kernel
> > or in user space.
> >
> > To be more precise we have to look at your DSDT.

^^^^^^^ **DSDT**.

> My SSDT table is:

^^^^ See the difference? I can't help here.

> DefinitionBlock ("gpio_button.aml", "SSDT", 5, "ASEMsp", "GPIO_BTN", 1)
> {
> External (_SB_.GPO1, DeviceObj)
>
> Scope (\_SB.GPO1)
> {
> Device (BTNS)
> {
> Name (_HID, "PRP0001")
> Name (_DDN, "GPIO buttons device")
>
> Name (_CRS, ResourceTemplate ()
> {
> GpioIo (
> Exclusive, // Not shared
> PullNone, // No need for pulls
> 0, // Debounce timeout
> 0, // Drive strength
> IoRestrictionInputOnly, // Only used as input
> "\\_SB.GPO1", // GPIO controller
> 0, ResourceConsumer, , ) // Must be 0
> {
> 1, // GPIO number
> }
> })
>
> Name (_DSD, Package () {
> ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> Package () {
> Package () {
> "gpio-line-names",
> Package () {
> "USER_PUSH_BUTTON",
> }
> },
> }
> })
> }
> }
> }
>
> And the kernel messages, after loading the table, are:
>
> ACPI: Host-directed Dynamic ACPI Table Load:
> ACPI: SSDT 0xFFFF908274285200 0000E8 (v05 ASEMsp GPIO_BTN 00000001 INTL 20200717)
> ACPI: \_SB_.GPO1.BTNS: PRP0001 requires 'compatible' property
>
> So I need a "consumer", but I don't want to export the GPIO using its number...
> If you have any suggestion ...

Define "gpio-line-names" property in the *provider* (controller)
device node _DSD().

--
With Best Regards,
Andy Shevchenko