From 7444a72effa632fcd8edc566f880d96fe213c73b Mon Sep 17 00:00:00 2001
From: Michael Buesch <mb@bu3sch.de>
Date: Fri, 25 Jul 2008 01:46:11 -0700
Subject: gpiolib: allow user-selection

This patch adds functionality to the gpio-lib subsystem to make it
possible to enable the gpio-lib code even if the architecture code didn't
request to get it built in.

The archtitecture code does still need to implement the gpiolib accessor
functions in its asm/gpio.h file.  This patch adds the implementations for
x86 and PPC.

With these changes it is possible to run generic GPIO expansion cards on
every architecture that implements the trivial wrapper functions.  Support
for more architectures can easily be added.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: David Brownell <david-b@pacbell.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Samuel Ortiz <sameo@openedhand.com>
Cc: Kumar Gala <galak@gate.crashing.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/gpio/Kconfig  | 33 +++++++++++++++++++++++++++++----
 drivers/gpio/Makefile |  2 +-
 2 files changed, 30 insertions(+), 5 deletions(-)

(limited to 'drivers/gpio')

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index de202dbe530..5a355f82916 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -2,15 +2,40 @@
 # GPIO infrastructure and expanders
 #
 
-config HAVE_GPIO_LIB
+config ARCH_WANT_OPTIONAL_GPIOLIB
 	bool
+	help
+	  Select this config option from the architecture Kconfig, if
+	  it is possible to use gpiolib on the architecture, but let the
+	  user decide whether to actually build it or not.
+	  Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does
+	  not depend on GPIOs being available, but rather let the user
+	  decide whether he needs it or not.
+
+config ARCH_REQUIRE_GPIOLIB
+	bool
+	select GPIOLIB
 	help
 	  Platforms select gpiolib if they use this infrastructure
 	  for all their GPIOs, usually starting with ones integrated
 	  into SOC processors.
+	  Selecting this from the architecture code will cause the gpiolib
+	  code to always get built in.
+
+
+
+menuconfig GPIOLIB
+	bool "GPIO Support"
+	depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB
+	select GENERIC_GPIO
+	help
+	  This enables GPIO support through the generic GPIO library.
+	  You only need to enable this, if you also want to enable
+	  one or more of the GPIO expansion card drivers below.
+
+	  If unsure, say N.
 
-menu "GPIO Support"
-	depends on HAVE_GPIO_LIB
+if GPIOLIB
 
 config DEBUG_GPIO
 	bool "Debug GPIO calls"
@@ -116,4 +141,4 @@ config GPIO_MCP23S08
 	  SPI driver for Microchip MCP23S08 I/O expander.  This provides
 	  a GPIO interface supporting inputs and outputs.
 
-endmenu
+endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index eeb2f2b2028..8c45948d1fe 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,7 +2,7 @@
 
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 
-obj-$(CONFIG_HAVE_GPIO_LIB)	+= gpiolib.o
+obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 
 obj-$(CONFIG_GPIO_MAX7301)	+= max7301.o
 obj-$(CONFIG_GPIO_MCP23S08)	+= mcp23s08.o
-- 
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