Re: [Linaro-acpi] example GPIO ASL

On 2013-6-18 1:16, Al Stone wrote:

Sorry I did not send this out sooner -- I rewrote it a several different times over the last week to play with some ideas...

Nonetheless, here's the simple bit of ASL I'm using for GPIO right now:

Scope (_SB) {

// Base Address: 0x11400000
Device (GPA0)            // GPIO controller GPA0
{
    Name (_HID, "LINA0002")
    Name (_UID, 0x00)

    Method (_CRS, 0x0, Serialized)
    {
        Name(RBUF, ResourceTemplate ()
        {
            Memory32Fixed (ReadWrite,
                       0x11400000,
                       0x18)
            GpioIo (Exclusive,
                PullDefault,
                ,    // debounce timeout
                ,    // drive strength
                ,    // IO restriction
                "GPA0")
                {    // pin numbers
                    0x00,
                    0x01,
                    0x02,
                    0x03,
                    0x04,
                    0x05,
                    0x06,
                    0x07
                }
        })
        Return(RBUF)
    }
}

}

This is still not quite working in the Samsung gpiolib code just yet. They never really used FDT before (or at least, not in a way I would consider proper) so I'm having to unwind some partial movement to FDT and their specific data structures.

GPIO interrupts are not going to be much different but I don't have a good example to send out just yet.

Hi Al,

Have you considered about GPIO-signaled ACPI Events in GPIO ASL?

Thanks Hanjun

You should be able to figure out the address from the current FDT. The pin numbers are much better hidden in mach-exynos/include/mach/gpio.h. Sometimes it's easier just to read them from /sys :).

I put this in an SSDT just for grins, but it can also go in the DSDT.