Set up a named device MMIO memory mapping in the GPIO controller's
parent device, map the virtual memory in the init function of the
parent device.
Once the controller's register space has been successfully mapped,
propagate the mapped virtual address to all child (= GPIO bank)
devices. While it is possible to add a named mapping to every
single GPIO bank device and initialize it in the respective bank
device's init function, this would result in multiple virtual
address mappings all pointing to the same 4k of physical memory.
I assume that, although all those mappings having the same attri-
butes, such a setup is at least discouraged.
Signed-off-by: Immo Birnbaum <mail@birnbaum.immo>
Driver implementation for the Xilinx Processor System MIO / EMIO GPIO
controller as contained in the Zynq-7000 and ZynqMP (UltraScale) SoCs.
The driver is split up into source and header for a parent controller
device and source and header for 1..n child GPIO pin bank devices.
The parent device driver takes care of IRQ handling, the GPIO pin bank
driver provides pin / bank access according to the API defined by the
GPIO subsystem.
More than one device for this type of GPIO controller is required as
it provides access to a number of GPIO pins well in excess of the 32
pins addressable by the current GPIO API (whereever parameters or
return values come in the form of a bit mask):
- Zynq-7000: 54 MIO GPIO pins, 64 EMIO GPIO pins in 4 banks.
- ZynqMP: 78 MIO GPIO pins, 96 EMIO GPIO pins in 6 banks.
Signed-off-by: Immo Birnbaum <Immo.Birnbaum@weidmueller.com>
