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>

18 files changed, 116 insertions, 23 deletions

diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 8b69811a9642..18022e249c53 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -389,11 +389,21 @@ either NULL or the label associated with that GPIO when it was requested.
 
 Platform Support
 ----------------
-To support this framework, a platform's Kconfig will "select HAVE_GPIO_LIB"
+To support this framework, a platform's Kconfig will "select" either
+ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB
 and arrange that its <asm/gpio.h> includes <asm-generic/gpio.h> and defines
 three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep().
 They may also want to provide a custom value for ARCH_NR_GPIOS.
 
+ARCH_REQUIRE_GPIOLIB means that the gpio-lib code will always get compiled
+into the kernel on that architecture.
+
+ARCH_WANT_OPTIONAL_GPIOLIB means the gpio-lib code defaults to off and the user
+can enable it and build it into the kernel optionally.
+
+If neither of these options are selected, the platform does not support
+GPIOs through GPIO-lib and the code cannot be enabled by the user.
+
 Trivial implementations of those functions can directly use framework
 code, which always dispatches through the gpio_chip:
 
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 6fb4f03369f2..dabb015aa40b 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -268,7 +268,7 @@ config ARCH_EP93XX
         select GENERIC_GPIO
         select HAVE_CLK
         select HAVE_CLK
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         help
           This enables support for the Cirrus EP93xx series of CPUs.
 
@@ -447,7 +447,7 @@ config ARCH_PXA
         select ARCH_MTD_XIP
         select GENERIC_GPIO
         select HAVE_CLK
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         select GENERIC_TIME
         select GENERIC_CLOCKEVENTS
         select TICK_ONESHOT
@@ -479,7 +479,7 @@ config ARCH_SA1100
         select GENERIC_CLOCKEVENTS
         select HAVE_CLK
         select TICK_ONESHOT
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         help
           Support for StrongARM 11x0 based boards.
 
@@ -522,7 +522,7 @@ config ARCH_OMAP
         bool "TI OMAP"
         select GENERIC_GPIO
         select HAVE_CLK
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         select GENERIC_TIME
         select GENERIC_CLOCKEVENTS
         help
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index df4adefedb42..7c239a916275 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -88,7 +88,7 @@ config PLATFORM_AT32AP
         select SUBARCH_AVR32B
         select MMU
         select PERFORMANCE_COUNTERS
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         select GENERIC_ALLOCATOR
 
 #
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index b9c754f4070c..b4c4eaa5dd26 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -713,7 +713,7 @@ config CSRC_SB1250
 
 config GPIO_TXX9
         select GENERIC_GPIO
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         bool
 
 config CFE
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index de6b49cd6be8..fe88418167c5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -110,6 +110,7 @@ config PPC
         default y
         select HAVE_DYNAMIC_FTRACE
         select HAVE_FTRACE
+        select ARCH_WANT_OPTIONAL_GPIOLIB
         select HAVE_IDE
         select HAVE_IOREMAP_PROT
         select HAVE_EFFICIENT_UNALIGNED_ACCESS
diff --git a/arch/powerpc/platforms/52xx/Kconfig b/arch/powerpc/platforms/52xx/Kconfig
index d664b1bce381..ccbd4958412e 100644
--- a/arch/powerpc/platforms/52xx/Kconfig
+++ b/arch/powerpc/platforms/52xx/Kconfig
@@ -48,6 +48,6 @@ config PPC_MPC5200_BUGFIX
 config PPC_MPC5200_GPIO
         bool "MPC5200 GPIO support"
         depends on PPC_MPC52xx
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         help
           Enable gpiolib support for mpc5200 based boards
diff --git a/arch/powerpc/sysdev/qe_lib/Kconfig b/arch/powerpc/sysdev/qe_lib/Kconfig
index 4bb18f57901e..1ce546462be5 100644
--- a/arch/powerpc/sysdev/qe_lib/Kconfig
+++ b/arch/powerpc/sysdev/qe_lib/Kconfig
@@ -29,7 +29,7 @@ config QE_GPIO
         bool "QE GPIO support"
         depends on QUICC_ENGINE
         select GENERIC_GPIO
-        select HAVE_GPIO_LIB
+        select ARCH_REQUIRE_GPIOLIB
         help
           Say Y here if you're going to use hardware that connects to the
           QE GPIOs.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 66f3ab05b18c..e3cba0b45600 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -23,6 +23,7 @@ config X86
         select HAVE_OPROFILE
         select HAVE_IOREMAP_PROT
         select HAVE_KPROBES
+        select ARCH_WANT_OPTIONAL_GPIOLIB if !X86_RDC321X
         select HAVE_KRETPROBES
         select HAVE_DYNAMIC_FTRACE
         select HAVE_FTRACE
diff --git a/drivers/Makefile b/drivers/Makefile
index 808e0ae66aa8..54ec5e718c0e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -5,7 +5,7 @@
 # Rewritten to use lists instead of if-statements.
 #
 
-obj-$(CONFIG_HAVE_GPIO_LIB)     += gpio/
+obj-y                           += gpio/
 obj-$(CONFIG_PCI)               += pci/
 obj-$(CONFIG_PARISC)            += parisc/
 obj-$(CONFIG_RAPIDIO)           += rapidio/
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index de202dbe5300..5a355f829167 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 eeb2f2b20282..8c45948d1fe7 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
diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 50e0a4653741..a95cb9465d65 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -126,7 +126,7 @@ config ISP1301_OMAP
 
 config TPS65010
         tristate "TPS6501x Power Management chips"
-        depends on HAVE_GPIO_LIB
+        depends on GPIOLIB
         default y if MACH_OMAP_H2 || MACH_OMAP_H3 || MACH_OMAP_OSK
         help
           If you say yes here you get support for the TPS6501x series of
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index bac9e973ece0..1f57a99fd968 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -36,7 +36,7 @@ config MFD_ASIC3
 
 config HTC_EGPIO
         bool "HTC EGPIO support"
-        depends on GENERIC_HARDIRQS && HAVE_GPIO_LIB && ARM
+        depends on GENERIC_HARDIRQS && GPIOLIB && ARM
         help
             This driver supports the CPLD egpio chip present on
             several HTC phones.  It provides basic support for input
@@ -52,7 +52,7 @@ config HTC_PASIC3
 
 config MFD_TC6393XB
         bool "Support Toshiba TC6393XB"
-        depends on HAVE_GPIO_LIB
+        depends on GPIOLIB
         select MFD_CORE
         help
           Support for Toshiba Mobile IO Controller TC6393XB
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 3a7a11a75fb4..1d7ec3129349 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -4,7 +4,7 @@ config OF_DEVICE
 
 config OF_GPIO
         def_bool y
-        depends on OF && PPC_OF && HAVE_GPIO_LIB
+        depends on OF && PPC_OF && GPIOLIB
         help
           OpenFirmware GPIO accessors
 
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 1beff5166e53..a3034d20ebd5 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -3,7 +3,7 @@
 
 #include <linux/types.h>
 
-#ifdef CONFIG_HAVE_GPIO_LIB
+#ifdef CONFIG_GPIOLIB
 
 #include <linux/compiler.h>
 
diff --git a/include/asm-mips/mach-generic/gpio.h b/include/asm-mips/mach-generic/gpio.h
index e6b376bd9d06..b4e70208da64 100644
--- a/include/asm-mips/mach-generic/gpio.h
+++ b/include/asm-mips/mach-generic/gpio.h
@@ -1,7 +1,7 @@
 #ifndef __ASM_MACH_GENERIC_GPIO_H
 #define __ASM_MACH_GENERIC_GPIO_H
 
-#ifdef CONFIG_HAVE_GPIO_LIB
+#ifdef CONFIG_GPIOLIB
 #define gpio_get_value  __gpio_get_value
 #define gpio_set_value  __gpio_set_value
 #define gpio_cansleep   __gpio_cansleep
diff --git a/include/asm-powerpc/gpio.h b/include/asm-powerpc/gpio.h
index 77ad3a890f30..ea04632399d8 100644
--- a/include/asm-powerpc/gpio.h
+++ b/include/asm-powerpc/gpio.h
@@ -17,7 +17,7 @@
 #include <linux/errno.h>
 #include <asm-generic/gpio.h>
 
-#ifdef CONFIG_HAVE_GPIO_LIB
+#ifdef CONFIG_GPIOLIB
 
 /*
  * We don't (yet) implement inlined/rapid versions for on-chip gpios.
@@ -51,6 +51,6 @@ static inline int irq_to_gpio(unsigned int irq)
         return -EINVAL;
 }
 
-#endif /* CONFIG_HAVE_GPIO_LIB */
+#endif /* CONFIG_GPIOLIB */
 
 #endif /* __ASM_POWERPC_GPIO_H */
diff --git a/include/asm-x86/gpio.h b/include/asm-x86/gpio.h
index ff87fca0caf9..116e9147fe66 100644
--- a/include/asm-x86/gpio.h
+++ b/include/asm-x86/gpio.h
@@ -1,6 +1,62 @@
+/*
+ * Generic GPIO API implementation for x86.
+ *
+ * Derived from the generic GPIO API for powerpc:
+ *
+ * Copyright (c) 2007-2008  MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
 #ifndef _ASM_I386_GPIO_H
 #define _ASM_I386_GPIO_H
 
+#ifdef CONFIG_X86_RDC321X
 #include <gpio.h>
+#else /* CONFIG_X86_RDC321X */
+
+#include <asm-generic/gpio.h>
+
+#ifdef CONFIG_GPIOLIB
+
+/*
+ * Just call gpiolib.
+ */
+static inline int gpio_get_value(unsigned int gpio)
+{
+        return __gpio_get_value(gpio);
+}
+
+static inline void gpio_set_value(unsigned int gpio, int value)
+{
+        __gpio_set_value(gpio, value);
+}
+
+static inline int gpio_cansleep(unsigned int gpio)
+{
+        return __gpio_cansleep(gpio);
+}
+
+/*
+ * Not implemented, yet.
+ */
+static inline int gpio_to_irq(unsigned int gpio)
+{
+        return -ENOSYS;
+}
+
+static inline int irq_to_gpio(unsigned int irq)
+{
+        return -EINVAL;
+}
+
+#endif /* CONFIG_GPIOLIB */
+
+#endif /* CONFIG_X86_RDC321X */
 
 #endif /* _ASM_I386_GPIO_H */