On Tue, Feb 23, 2016 at 7:30 AM, Peter Hung [off-list ref] wrote:

This driver is GPIOLIB driver for F81504/508/512, it'll handle the
GPIOLIB operation of this device. This module will depend on
MFD_FINTEK_F81504_CORE.

IC function list:
    F81504: Max 2x8 GPIOs and max 4 serial ports
        port2/3 are multi-function
    F81508: Max 6x8 GPIOs and max 8 serial ports
        port2/3 are multi-function, port8/9/10/11 are gpio only
    F81512: Max 6x8 GPIOs and max 12 serial ports
        port2/3/8/9/10/11 are multi-function

GPIO register:
PCI Configuration space:
    F0h: bit0~5: Enable GPIO0~5
         bit6~7: Reserve
    F3h: bit0~5: Multi-Functional Flag (0:GPIO/1:UART)
         bit0: UART2 pin out for UART2 / GPIO0
         bit1: UART3 pin out for UART3 / GPIO1
         bit2: UART8 pin out for UART8 / GPIO2
         bit3: UART9 pin out for UART9 / GPIO3
         bit4: UART10 pin out for UART10 / GPIO4
         bit5: UART11 pin out for UART11 / GPIO5
         bit6~7: Reserve
    F1h: IO address (LSB)
    F2h: IO address (MSB)
    F8h + 8 * set: Direction control (bitwise)
         bitx: 0 - Input mode
         bitx: 1 - Output mode
    F9h + 8 * set: Drive ability control (bitwise)
         bitx: 0 - Open drain (default)
         bitx: 1 - Push Pull
         In this driver, we only implements open drain mode.

IO space:
    (IO base + 0~5): GPIO-0x~5x in/out value (bitwise)

Suggested-by: One Thousand Gnomes <redacted>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Peter Hung <redacted>

I assume this must do in through the MFD or TTY tree with the rest.
There is a new devm_gpiochip_add_data() coming into the GPIO tree
but we can patch it to use that later. (Note to Laxman to revisit...)

Acked-by: Linus Walleij <redacted>

Yours,
Linus Walleij