Add the pxa25x architecture, which is a pxa2xx with 85 pins. The
registers spacing, and pins logic is common to pxa2xx, only the pins and
their alternate function are specific to pxa25x.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Add the pxa27x architecture, which is a pxa2xx with 128 pins. The
registers spacing, and pins logic is common to pxa2xx, only the pins and
their alternate function are specific to pxa27x.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Add a pincontrol driver for pxa2xx architecture, encompassing all pxa25x
and pxa27x variants. This is only the pin muxing part of the driver.

One specific consideration is also the memory space (MMIO), which is
intertwined with the GPIO registers. To make things worse, the GPIO
direction register also affect pin muxing, as it chooses the "kind" of
pin, ie. the 4 output functions or 4 input functions.

The mapping between pinctrl notions and PXA Technical Reference Manual
is as follows :
 - a pin is obviously a pin
 - a group is also a pin, ie. group P101 is the pin 101
 - a mux function is an alternate function
   (ie. gpio-in, gpio-out, MMCLK, BTRTS, etc ...)

The individual architecture (pxa27x, pxa25x) instantiate a pin control
by providing a table of pins, each pin being provided a list of
PXA_FUNCTION (alternate functions).

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>