gpio: add driver for basic memory-mapped GPIO controllers

The basic GPIO controllers may be found in various on-board FPGA and ASIC
solutions that are used to control board's switches, LEDs, chip-selects,
Ethernet/USB PHY power, etc.

These controllers may not provide any means of pin setup
(in/out/open drain).

The driver supports:
- 8/16/32/64 bits registers;
- GPIO controllers with clear/set registers;
- GPIO controllers with a single "data" register;
- Big endian bits/GPIOs ordering (mostly used on PowerPC).

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>,
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fc6019d..3ff0651 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -10,6 +10,7 @@
 
 obj-$(CONFIG_GPIO_ADP5520)	+= adp5520-gpio.o
 obj-$(CONFIG_GPIO_ADP5588)	+= adp5588-gpio.o
+obj-$(CONFIG_GPIO_BASIC_MMIO)	+= basic_mmio_gpio.o
 obj-$(CONFIG_GPIO_LANGWELL)	+= langwell_gpio.o
 obj-$(CONFIG_GPIO_MAX730X)	+= max730x.o
 obj-$(CONFIG_GPIO_MAX7300)	+= max7300.o