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gpiolib: allow user-selection

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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>
This commit is contained in:
Michael Buesch
2008-07-25 01:46:11 -07:00
committed by Linus Torvalds
parent ff1d5c2f02
commit 7444a72eff
18 changed files with 116 additions and 23 deletions
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33
drivers/gpio/Kconfig
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@ -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.
menu "GPIO Support"
depends on HAVE_GPIO_LIB
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.
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