At present if an optional Kconfig value needs to be used it must be bracketed by #ifdef. For example, with this Kconfig setup:
config WIBBLE bool "Support wibbles, the world needs more wibbles"
config WIBBLE_ADDR hex "Address of the wibble" depends on WIBBLE
then the following code must be used:
#ifdef CONFIG_WIBBLE static void handle_wibble(void) { int val = CONFIG_WIBBLE_ADDR;
... } #endif
static void init_machine() { ... #ifdef CONFIG_WIBBLE handle_wibble(); #endif }
Add a new IF_ENABLED_INT() to help with this. So now it is possible to write, without #ifdefs:
static void handle_wibble(void) { int val = IF_ENABLED_INT(CONFIG_WIBBLE, CONFIG_WIBBLE_ADDR);
... }
static void init_machine() { ... if (IS_ENABLED(CONFIG_WIBBLE)) handle_wibble(); }
The value will be 0 if CONFIG_WIBBLE is not defined, and CONFIG_WIBBLE_ADDR if it is. This allows us to reduce the use of #ifdef in the code, ensuring that the compiler still checks the code even if it is not ultimately used for a particular build.
Signed-off-by: Simon Glass sjg@chromium.org ---
include/linux/kconfig.h | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/include/linux/kconfig.h b/include/linux/kconfig.h index 3a2da738c4..86cd266540 100644 --- a/include/linux/kconfig.h +++ b/include/linux/kconfig.h @@ -79,6 +79,18 @@ */ #define CONFIG_VAL(option) config_val(option)
+/* This use a similar mechanism to config_enabled() above */ +#define config_opt_enabled(cfg, opt_cfg) _config_opt_enabled(cfg, opt_cfg) +#define _config_opt_enabled(cfg_val, opt_value) \ + __config_opt_enabled(__ARG_PLACEHOLDER_##cfg_val, opt_value) +#define __config_opt_enabled(arg1_or_junk, arg2) \ + ___config_opt_enabled(arg1_or_junk arg2, 0) +#define ___config_opt_enabled(__ignored, val, ...) val + +/* Evaluates to 0 if option is not defined, int_option if it is defined */ +#define IF_ENABLED_INT(option, int_option) \ + config_opt_enabled(option, int_option) + /* * CONFIG_IS_ENABLED(FOO) evaluates to * 1 if CONFIG_SPL_BUILD is undefined and CONFIG_FOO is set to 'y' or 'm',