After power on, it is recommended that the driver resets the device.
The reset procedure timing is described in the datasheet and is used
at device init (before writing device configuration) and
for power management. It is a sequence of setting the interrupt
and reset pins high/low at specific timing intervals. This procedure
also includes setting the slave address to the one specified in the
ACPI/device tree.

This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
driver gt9xx.c for Android (publicly available in Android kernel
trees for various devices).

For reset the driver needs to control the interrupt and
reset gpio pins (configured through ACPI/device tree). For devices
that do not have the gpio pins properly declared, the functionality
depending on these pins will not be available, but the device can still
be used with basic functionality.

For both device tree and ACPI, the interrupt gpio pin configuration is
read from the "irq-gpios" property and the reset pin configuration is
read from the "reset-gpios" property. For ACPI 5.1, named properties
can be specified using the _DSD section. This functionality will not be
available for devices that use indexed gpio pins declared in the _CRS
section (we need to provide backward compatibility with devices
that do not support using the interrupt gpio pin as output).

For ACPI, the pins can be specified using ACPI 5.1:
Device (STAC)
{
    Name (_HID, "GDIX1001")
    ...

    Method (_CRS, 0, Serialized)
    {
        Name (RBUF, ResourceTemplate ()
        {
            I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
                AddressingMode7Bit, "\\I2C0",
                0x00, ResourceConsumer, ,
                )

            GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
                "\\I2C0", 0x00, ResourceConsumer, ,
                 )
                 {   // Pin list
                     0
                 }

            GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
                IoRestrictionOutputOnly, "\\I2C0", 0x00,
                ResourceConsumer, ,
                )
                {
                     1
                }
        })
        Return (RBUF)
    }

    Name (_DSD,  Package ()
    {
        ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
        Package ()
        {
            Package (2) {"irq-gpios", Package() {^STAC, 0, 0, 0 }},
            Package (2) {"reset-gpios", Package() {^STAC, 1, 0, 0 }},
            ...
        }
    }
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com>
Signed-off-by: NIrina Tirdea <irina.tirdea@intel.com>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NBastien Nocera <hadess@hadess.net>
Tested-by: NBastien Nocera <hadess@hadess.net>
Tested-by: NAleksei Mamlin <mamlinav@gmail.com>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

This change adds device tree support and binding information for Goodix
GT9xx series touchscreen controller.  It also adds support for 5-finger
chips, like GT911 and GT912, which can be found on ARM tablets, such as
Wexler TAB7200 and MSI Primo73.

Datasheets can be found here:
https://drive.google.com/folderview?id=0BxCVOQS3ZymGfmJyY2RKbE5XbVlKNlktVTlwV0lxNEdxd2dzeWZER094cmJPVnMxN1F0Yzg&usp=sharingSigned-off-by: NAleksei Mamlin <mamlinav@gmail.com>
Reviewed-by: NBastien Nocera <hadess@hadess.net>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>