GPIO Enablement with ACPI

Status

Added ACPI support for I.MX GPIO controller.
- [Linux] https://gitlab.com/LinaroLtd/clientpc/linux/-/merge_requests/4
- [EDK2] https://gitlab.com/LinaroLtd/clientpc/edk2-platforms/-/merge_requests/2
- Depend on the ACPI pinctrl subsystem - https://linaro.atlassian.net/wiki/spaces/CLIENTPC/pages/28831285713

AML Code Snippet

Device (GPI1)
{
    Name (_HID, "NXP0103")
    Name (_UID, 0x0)
    ...
  
    Method (_CRS, 0x0, NotSerialized) {
        Name (RBUF, ResourceTemplate () {
                MEMORY32FIXED(ReadWrite, 0x30200000, 0x50000, )  // GPIO1
                MEMORY32FIXED(ReadWrite, 0x30330000, 0x10000, )  // IOMUXC
                Interrupt(ResourceConsumer, Level, ActiveHigh, Exclusive) { 96, 97 }
        })
        Return(RBUF)
    }
    Name (_DSD, Package () {
        ToUUID ("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
        Package () {
            Package (2) {"gpio-base", 0},
            Package (2) {"num-maps", 1},
            Package (2) {"pin-controller-0", "\\_SB.PINC"},
            Package (2) {"gpio-range-0", Package() { 0, 5, 30 } }
        }
    })
}

I.MX GPIO driver requires a few extra data like GPIO to PIN number mapping and the pin-controller device node etc. they are provided through _DSD methods.

Note: Later discussion with a kernel maintainer suggested we should use the DT properties for GPIO to PIN number mapping in _DSD. We haven’t investigated this yet.