[PATCH v3] gpiolib: Allow user-selection

From: Michael Buesch
Date: Thu Jul 10 2008 - 13:18:54 EST

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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@xxxxxxxxx>

---

This patch should be scheduled for the next kernel feature merge window.
This is diffed against current linux-next.

The defconfig patching was removed since the last version of the patch.
defconfigs will automatically get updated.

Index: linux-next/arch/x86/Kconfig
===================================================================
--- linux-next.orig/arch/x86/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/x86/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -27,6 +27,7 @@ config X86
select HAVE_FTRACE
select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64)
select HAVE_ARCH_KGDB if !X86_VOYAGER
+ select ARCH_WANT_OPTIONAL_GPIOLIB if !X86_RDC321X

config ARCH_DEFCONFIG
string
Index: linux-next/include/asm-x86/gpio.h
===================================================================
--- linux-next.orig/include/asm-x86/gpio.h 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/include/asm-x86/gpio.h 2008-07-10 19:01:37.000000000 +0200
@@ -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@xxxxxxxxxxxxx>
+ *
+ * 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 */
Index: linux-next/arch/powerpc/Kconfig
===================================================================
--- linux-next.orig/arch/powerpc/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/powerpc/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -113,6 +113,7 @@ config PPC
select HAVE_LMB
select USE_GENERIC_SMP_HELPERS if SMP
select HAVE_OPROFILE
+ select ARCH_WANT_OPTIONAL_GPIOLIB

config EARLY_PRINTK
bool
Index: linux-next/drivers/gpio/Kconfig
===================================================================
--- linux-next.orig/drivers/gpio/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/gpio/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -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"
@@ -76,4 +101,4 @@ config GPIO_MCP23S08
SPI driver for Microchip MCP23S08 I/O expander. This provides
a GPIO interface supporting inputs and outputs.

-endmenu
+endif
Index: linux-next/drivers/gpio/Makefile
===================================================================
--- linux-next.orig/drivers/gpio/Makefile 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/gpio/Makefile 2008-07-10 19:01:37.000000000 +0200
@@ -2,7 +2,7 @@

ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG

-obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o
+obj-$(CONFIG_GPIOLIB) += gpiolib.o

obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
obj-$(CONFIG_GPIO_PCA953X) += pca953x.o
Index: linux-next/Documentation/gpio.txt
===================================================================
--- linux-next.orig/Documentation/gpio.txt 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/Documentation/gpio.txt 2008-07-10 19:01:37.000000000 +0200
@@ -392,11 +392,21 @@ either NULL or the label associated with

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:

Index: linux-next/arch/arm/Kconfig
===================================================================
--- linux-next.orig/arch/arm/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/arm/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -262,7 +262,7 @@ config ARCH_EP93XX
select ARM_AMBA
select ARM_VIC
select GENERIC_GPIO
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
help
This enables support for the Cirrus EP93xx series of CPUs.

@@ -430,7 +430,7 @@ config ARCH_PXA
depends on MMU
select ARCH_MTD_XIP
select GENERIC_GPIO
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
select GENERIC_TIME
select GENERIC_CLOCKEVENTS
select TICK_ONESHOT
@@ -461,7 +461,7 @@ config ARCH_SA1100
select GENERIC_TIME
select GENERIC_CLOCKEVENTS
select TICK_ONESHOT
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
help
Support for StrongARM 11x0 based boards.

@@ -501,7 +501,7 @@ config ARCH_DAVINCI
config ARCH_OMAP
bool "TI OMAP"
select GENERIC_GPIO
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
select GENERIC_TIME
select GENERIC_CLOCKEVENTS
help
Index: linux-next/arch/avr32/Kconfig
===================================================================
--- linux-next.orig/arch/avr32/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/avr32/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -87,7 +87,7 @@ config PLATFORM_AT32AP
select SUBARCH_AVR32B
select MMU
select PERFORMANCE_COUNTERS
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
select GENERIC_ALLOCATOR

#
Index: linux-next/arch/mips/Kconfig
===================================================================
--- linux-next.orig/arch/mips/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/mips/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -748,7 +748,7 @@ config CSRC_SB1250

config GPIO_TXX9
select GENERIC_GPIO
- select HAVE_GPIO_LIB
+ select ARCH_REQUIRE_GPIOLIB
bool

config CFE
Index: linux-next/arch/powerpc/platforms/52xx/Kconfig
===================================================================
--- linux-next.orig/arch/powerpc/platforms/52xx/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/powerpc/platforms/52xx/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -47,6 +47,6 @@ 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
Index: linux-next/drivers/Makefile
===================================================================
--- linux-next.orig/drivers/Makefile 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/Makefile 2008-07-10 19:01:37.000000000 +0200
@@ -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/
Index: linux-next/drivers/i2c/chips/Kconfig
===================================================================
--- linux-next.orig/drivers/i2c/chips/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/i2c/chips/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -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
Index: linux-next/drivers/mfd/Kconfig
===================================================================
--- linux-next.orig/drivers/mfd/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/mfd/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -28,7 +28,7 @@ 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
@@ -44,7 +44,7 @@ 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
Index: linux-next/drivers/of/Kconfig
===================================================================
--- linux-next.orig/drivers/of/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/drivers/of/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -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

Index: linux-next/include/asm-generic/gpio.h
===================================================================
--- linux-next.orig/include/asm-generic/gpio.h 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/include/asm-generic/gpio.h 2008-07-10 19:01:37.000000000 +0200
@@ -3,7 +3,7 @@

#include <linux/types.h>

-#ifdef CONFIG_HAVE_GPIO_LIB
+#ifdef CONFIG_GPIOLIB

#include <linux/compiler.h>

Index: linux-next/include/asm-mips/mach-generic/gpio.h
===================================================================
--- linux-next.orig/include/asm-mips/mach-generic/gpio.h 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/include/asm-mips/mach-generic/gpio.h 2008-07-10 19:01:37.000000000 +0200
@@ -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
Index: linux-next/include/asm-powerpc/gpio.h
===================================================================
--- linux-next.orig/include/asm-powerpc/gpio.h 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/include/asm-powerpc/gpio.h 2008-07-10 19:01:37.000000000 +0200
@@ -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 i
return -EINVAL;
}

-#endif /* CONFIG_HAVE_GPIO_LIB */
+#endif /* CONFIG_GPIOLIB */

#endif /* __ASM_POWERPC_GPIO_H */
Index: linux-next/arch/powerpc/sysdev/qe_lib/Kconfig
===================================================================
--- linux-next.orig/arch/powerpc/sysdev/qe_lib/Kconfig 2008-07-10 19:00:16.000000000 +0200
+++ linux-next/arch/powerpc/sysdev/qe_lib/Kconfig 2008-07-10 19:01:37.000000000 +0200
@@ -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.

--
Greetings Michael.
--
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