This is the bulk of GPIO changes for the v4.20 series: Core changes: - A patch series from Hans Verkuil to make it possible to enable/disable IRQs on a GPIO line at runtime and drive GPIO lines as output without having to put/get them from scratch. The irqchip callbacks have been improved so that they can use only the fastpatch callbacks to enable/disable irqs like any normal irqchip, especially the gpiod_lock_as_irq() has been improved to be callable in fastpath context. A bunch of rework had to be done to achieve this but it is a big win since I never liked to restrict this to slowpath. The only call requireing slowpath was try_module_get() and this is kept at the .request_resources() slowpath callback. In the GPIO CEC driver this is a big win sine a single line is used for both outgoing and incoming traffic, and this needs to use IRQs for incoming traffic while actively driving the line for outgoing traffic. - Janusz Krzysztofik improved the GPIO array API to pass a "cookie" (struct gpio_array) and a bitmap for setting or getting multiple GPIO lines at once. This improvement orginated in a specific need to speed up an OMAP1 driver and has led to a much better API and real performance gains when the state of the array can be used to bypass a lot of checks and code when we want things to go really fast. The previous code would minimize the number of calls down to the driver callbacks assuming the CPU speed was orders of magnitude faster than the I/O latency, but this assumption was wrong on several platforms: what we needed to do was to profile and improve the speed on the hot path of the array functions and this change is now completed. - Clean out the painful and hard to grasp BNF experiments from the device tree bindings. Future approaches are looking into using JSON schema for this purpose. (Rob Herring is floating a patch series.) New drivers: - The RCAR driver now supports r8a774a1 (RZ/G2M). - Synopsys GPIO via CREGs driver. Major improvements: - Modernization of the EP93xx driver to use irqdomain and other contemporary concepts. - The ingenic driver has been merged into the Ingenic pin control driver and removed from the GPIO subsystem. - Debounce support in the ftgpio010 driver.