Re: [patch 2.6.24-rc6-mm 1/9] gpiolib: add drivers/gpio directory

David Brownell
2007-12-29T18:36:07Z

On Friday 28 December 2007, Sam Ravnborg wrote:
> kconfig symbols that are "select" targets should be named "HAVE_" so in
> this case you could use HAVE_GPIO_LIB.
> This is by convention only but introduced to make it visible that this is
> a config symbol supposed to be selected.

Not widely adopted yet, but of course such things take time.

> Then on top of that the HAVE_ symbols should not have any dependencies
> so we avoid that "select" selects a symbol where the dependencies are
> not fulfilled.

That limitation of "select" still seems more buglike to me than
anything else, FWIW. Not that it matters in this case.

> In your case you could just use
> obj-y += gpio/
>
> in the Makefile and then there is no need to actually reference the
> kconfig symbol.

No, that just shifts the reference into the drivers/gpio Makefilee.

> ccflags-$(CONFIG_DEBUG_GPIO) := -DDEBUG

Another new convention. :)

Pretty much like the folowing, then?

- Dave

============== CUT HERE
Kbuild/Kconfig feedback from Sam Ravnborg, adopting new conventions:

- HAVE_* for Kconfig symbols that platforms will select

- Descend into drivers/gpio unconditionally, letting the Makefile
sort out the differences

- Use "ccflags-$(CONGIF_DEBUG_GPIO) += -DDEBUG" instead of
those ugly (but traditional) conditionals.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
---
arch/arm/Kconfig | 4 +-
arch/avr32/Kconfig | 2 +-
drivers/Makefile | 2 +-
drivers/gpio/Kconfig | 4 ++--
drivers/gpio/Makefile | 10 ++++------
include/asm-generic/gpio.h | 2 +-
6 files changed, 10 insertions(+), 12 deletions(-)

--- at91.orig/arch/arm/Kconfig
+++ at91/arch/arm/Kconfig
@@ -346,7 +346,7 @@ config ARCH_PXA
select GENERIC_GPIO
select GENERIC_TIME
select GENERIC_CLOCKEVENTS
- select GPIO_LIB
+ select HAVE_GPIO_LIB
help
Support for Intel/Marvell's PXA2xx/PXA3xx processor line.

--- at91.orig/arch/avr32/Kconfig
+++ at91/arch/avr32/Kconfig
@@ -80,7 +80,7 @@ config PLATFORM_AT32AP
select SUBARCH_AVR32B
select MMU
select PERFORMANCE_COUNTERS
- select GPIO_LIB
+ select HAVE_GPIO_LIB

choice
prompt "AVR32 CPU type"
--- at91.orig/drivers/Makefile
+++ at91/drivers/Makefile
@@ -5,7 +5,7 @@
# Rewritten to use lists instead of if-statements.
#

-obj-$(CONFIG_GPIO_LIB) += gpio/
+obj-y += gpio/
obj-$(CONFIG_PCI) += pci/
obj-$(CONFIG_PARISC) += parisc/
obj-$(CONFIG_RAPIDIO) += rapidio/
--- at91.orig/drivers/gpio/Kconfig
+++ at91/drivers/gpio/Kconfig
@@ -2,7 +2,7 @@
# GPIO infrastructure and expanders
#

-config GPIO_LIB
+config HAVE_GPIO_LIB
bool
help
Platforms select gpiolib if they use this infrastructure
@@ -10,7 +10,7 @@ config GPIO_LIB
into SOC processors.

menu "GPIO Support"
- depends on GPIO_LIB
+ depends on HAVE_GPIO_LIB

config DEBUG_GPIO
bool "Debug GPIO calls"
--- at91.orig/drivers/gpio/Makefile
+++ at91/drivers/gpio/Makefile
@@ -1,12 +1,10 @@
# gpio support: dedicated expander chips, etc

+ccflags-$(CONGIF_DEBUG_GPIO) += -DDEBUG
+
+obj-$(CONFIG_HAVE_GPIO_LIB) += gpiolib.o
+
obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
obj-$(CONFIG_GPIO_PCA9539) += pca9539.o
obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o

-ifeq ($(CONFIG_DEBUG_GPIO),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
-
-obj-$(CONFIG_GPIO_LIB) += gpiolib.o
-
--- at91.orig/include/asm-generic/gpio.h
+++ at91/include/asm-generic/gpio.h
@@ -1,7 +1,7 @@
#ifndef _ASM_GENERIC_GPIO_H
#define _ASM_GENERIC_GPIO_H

-#ifdef CONFIG_GPIO_LIB
+#ifdef CONFIG_HAVE_GPIO_LIB

/* Platforms may implement their GPIO interface with library code,
* at a small performance cost for non-inlined operations and some