On Mon, Aug 26, 2013 at 12:08 PM, Chen Gang <gang.chen@xxxxxxxxxxx> wrote: > When GPIOLIB disabled, __gpio_get_value() and __gpio_set_value() will > not implement, so need remove them, or compiling fails. > > e.g. (allmodconfig for h8300) > > CC arch/h8300/kernel/h8300_ksyms.o > In file included from arch/h8300/include/generated/asm/gpio.h:1:0, > from arch/h8300/kernel/h8300_ksyms.c:17: > include/asm-generic/gpio.h: In function 'gpio_get_value_cansleep': > include/asm-generic/gpio.h:270:2: error: implicit declaration of function '__gpio_get_value' [-Werror=implicit-function-declaration] > return __gpio_get_value(gpio); > ^ > > For __gpio_get_value(), according to its implementation, it is enough > to use "return 0" instead of, and for __gpio_set_value(), just remove > directly. > > > Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx> NAK, this is not how you do it. This fallback path is for GENERIC_GPIO without GPIOLIB. Including it from a file indicates that you *are* using GENERIC_GPIO when GPIOLIB is not activated. It can not be used to stub out gpiolib. This is a better alternative: let h8300 select ARCH_HAVE_CUSTOM_GPIO_H This is quite common: $ git grep ARCH_HAVE_CUSTOM_GPIO_H arch/arm/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H arch/avr32/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H arch/blackfin/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H arch/m68k/Kconfig.cpu: select ARCH_HAVE_CUSTOM_GPIO_H arch/mips/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H arch/sh/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H arch/unicore32/Kconfig: select ARCH_HAVE_CUSTOM_GPIO_H Then put your stubs for __gpio_get_value() etc in arch/h8300/include/asm/gpio.h This way the h8300 will have a stub implementation if GPIOLIB is not selected. Be sure to put a comment about this in that file. Note: I'm still a bit rookie as GPIO maintainer so if Grant or Russell tells me I'm telling you wrong things: listen to them. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
