This is the bulk of GPIO changes for the v4.12 kernel cycle: Core changes - Return NULL from gpiod_get_optional() when GPIOLIB is disabled. This was a much discussed change. It affects use cases where people write drivers that might or might not be using GPIO resources. I have decided that this is the lesser evil right now. - Make gpiod_count() behave consistently across different hardware descriptions. - Fix the syntax around open drain/open source to not infer active high/low semantics. New drivers - A new single-register fixed-direction framework driver for hardware that have lines controlled by a single register that just work in one direction (out or in), including IRQ support. - Support the Fintek F71889A GPIO SuperIO controller. - Support the National NI 169445 MMIO GPIO. - Support for the X-Gene derivative of the DWC GPIO controller - Support for the Rohm BD9571MWV-M PMIC GPIO controller. - Refactor the Gemini GPIO driver to a generic Faraday FTGPIO driver and replace both the Gemini and the Moxa ART custom drivers with this driver. Driver improvements - A whole slew of drivers have their spinlocks chaned to raw spinlocks as they provide irqchips, and thus we are progressing on realtime compliance. - Use devm_irq_alloc_descs() in a slew of drivers, getting managed resources. - Support for the embedded PWM controller inside the MVEBU driver. - Debounce, open source and open drain support for the Aspeed driver. - Misc smaller fixes like spelling and syntax and whatnot.