MIPS: Alchemy: Rewrite GPIO support.

The current in-kernel Alchemy GPIO support is far too inflexible for
all my use cases.  To address this, the following changes are made:

* create generic functions which deal with manipulating the on-chip
  GPIO1/2 blocks.  Such functions are universally useful.
* Macros for GPIO2 shared interrupt management and block control.
* support for both built-in CONFIG_GPIOLIB and fast, inlined GPIO macros.

  If CONFIG_GPIOLIB is not enabled, provide linux gpio framework
  compatibility by directly inlining the GPIO1/2 functions.  GPIO access
  is limited to on-chip ones and they can be accessed as documented in
  the datasheets (GPIO0-31 and 200-215).

  If CONFIG_GPIOLIB is selected, two (2) gpio_chip-s, one for GPIO1 and
  one for GPIO2, are registered.  GPIOs can still be accessed by using
  the numberspace established in the databooks.

  However this is not yet flexible enough for my uses:  My Alchemy
  systems have a documented "external" gpio interface (fixed, different
  numberspace) and can support a variety of baseboards, some of which
  are equipped with I2C gpio expanders.  I want to be able to provide
  the default 16 GPIOs of the CPU board numbered as 0..15 and also
  support gpio expanders, if present, starting as gpio16.

  To achieve this, a new Kconfig symbol for Alchemy is introduced,
  CONFIG_ALCHEMY_GPIO_INDIRECT, which boards can enable to signal
  that they don't want the Alchemy numberspace exposed to the outside
  world, but instead want to provide their own.  Boards are now respon-
  sible for providing the linux gpio interface glue code (either in a
  custom gpio.h header (in board include directory) or with gpio_chips).

  To make the board-specific inlined gpio functions work, the MIPS
  Makefile must be changed so that the mach-au1x00/gpio.h header is
  included _after_ the board headers, by moving the inclusion of
  the mach-au1x00/ to the end of the header list.

  See arch/mips/include/asm/mach-au1x00/gpio.h for more info.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Acked-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -183,7 +183,6 @@ load-$(CONFIG_MACH_JAZZ)	+= 0xffffffff80080000
 # Common Alchemy Au1x00 stuff
 #
 core-$(CONFIG_SOC_AU1X00)	+= arch/mips/alchemy/common/
-cflags-$(CONFIG_SOC_AU1X00)	+= -I$(srctree)/arch/mips/include/asm/mach-au1x00
 
 #
 # AMD Alchemy Pb1000 eval board
@@ -281,6 +280,10 @@ load-$(CONFIG_MIPS_MTX1)	+= 0xffffffff80100000
 libs-$(CONFIG_MIPS_XXS1500)	+= arch/mips/alchemy/xxs1500/
 load-$(CONFIG_MIPS_XXS1500)	+= 0xffffffff80100000
 
+# must be last for Alchemy systems for GPIO to work properly
+cflags-$(CONFIG_SOC_AU1X00)	+= -I$(srctree)/arch/mips/include/asm/mach-au1x00
+
+
 #
 # Cobalt Server
 #

arch/mips/alchemy/Kconfig

@@ -1,3 +1,14 @@
+# au1000-style gpio
+config ALCHEMY_GPIO_AU1000
+	bool
+
+# select this in your board config if you don't want to use the gpio
+# namespace as documented in the manuals.  In this case however you need
+# to create the necessary gpio_* functions in your board code/headers!
+# see arch/mips/include/asm/mach-au1x00/gpio.h   for more information.
+config ALCHEMY_GPIO_INDIRECT
+	def_bool n
+
 choice
 	prompt "Machine type"
 	depends on MACH_ALCHEMY
@@ -108,22 +119,27 @@ endchoice
 config SOC_AU1000
 	bool
 	select SOC_AU1X00
+	select ALCHEMY_GPIO_AU1000
 
 config SOC_AU1100
 	bool
 	select SOC_AU1X00
+	select ALCHEMY_GPIO_AU1000
 
 config SOC_AU1500
 	bool
 	select SOC_AU1X00
+	select ALCHEMY_GPIO_AU1000
 
 config SOC_AU1550
 	bool
 	select SOC_AU1X00
+	select ALCHEMY_GPIO_AU1000
 
 config SOC_AU1200
 	bool
 	select SOC_AU1X00
+	select ALCHEMY_GPIO_AU1000
 
 config SOC_AU1X00
 	bool
@@ -134,4 +150,5 @@ config SOC_AU1X00
 	select SYS_HAS_CPU_MIPS32_R1
 	select SYS_SUPPORTS_32BIT_KERNEL
 	select SYS_SUPPORTS_APM_EMULATION
-	select ARCH_REQUIRE_GPIOLIB
+	select GENERIC_GPIO
+	select ARCH_WANT_OPTIONAL_GPIOLIB

arch/mips/alchemy/common/Makefile

@@ -7,7 +7,14 @@
 
 obj-y += prom.o irq.o puts.o time.o reset.o \
 	clocks.o platform.o power.o setup.o \
-	sleeper.o dma.o dbdma.o gpio.o
+	sleeper.o dma.o dbdma.o
+
+# optional gpiolib support
+ifeq ($(CONFIG_ALCHEMY_GPIO_INDIRECT),)
+ ifeq ($(CONFIG_GPIOLIB),y)
+  obj-$(CONFIG_ALCHEMY_GPIO_AU1000) += gpiolib-au1000.o
+ endif
+endif
 
 obj-$(CONFIG_PCI)		+= pci.o