From ecf877ef7c5c737b0ae874eb9521e88ab8a03a0a Mon Sep 17 00:00:00 2001 From: Brian Masney Date: Tue, 8 Sep 2026 13:47:18 -0400 Subject: driver: core: add subsys_driver() macro Add a new macro subsys_driver() to eliminate some boilerplate code in drivers that need to register earlier in the boot at the subsys_initcall level. Signed-off-by: Brian Masney Assisted-by: Claude:claude-opus-4-8 Reviewed-by: Geert Uytterhoeven Reviewed-by: Abel Vesa Tested-by: Pankaj Patil Link: https://lore.kernel.org/r/20260908-subsys_initcall-v1-1-cbccf4cd4288@redhat.com Signed-off-by: Bjorn Andersson --- include/linux/device/driver.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'include/linux') diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index 768a1334c0a1..29fbc01ef06f 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -297,4 +297,35 @@ static int __init __driver##_init(void) \ } \ device_initcall(__driver##_init); +/** + * subsys_driver() - Helper macro for drivers that don't do anything special + * in init/exit but have to register earlier, at subsys_initcall level, when + * built in. This eliminates a lot of boilerplate. Each driver may only use + * this macro once, and calling it replaces the init/exit boilerplate. + * + * @__driver: driver name + * @__register: register function for this driver type + * @__unregister: unregister function for this driver type + * @...: Additional arguments to be passed to __register and __unregister. + * + * This is meant to be a direct parallel of module_driver() above, but with + * the init call promoted to subsys_initcall() for built-in drivers so they + * are available earlier during boot. When built as a module subsys_initcall() + * collapses to module_init() and the normal module init/exit paths are used. + * + * Use this macro to construct bus specific macros for registering drivers, + * and do not use it on its own. + */ +#define subsys_driver(__driver, __register, __unregister, ...) \ +static int __init __driver##_init(void) \ +{ \ + return __register(&(__driver), ##__VA_ARGS__); \ +} \ +subsys_initcall(__driver##_init) \ +static void __exit __driver##_exit(void) \ +{ \ + __unregister(&(__driver), ##__VA_ARGS__); \ +} \ +module_exit(__driver##_exit) + #endif /* _DEVICE_DRIVER_H_ */ -- cgit v1.2.3 From e32faed77b268c13c924a5c35f9fe82f3791690c Mon Sep 17 00:00:00 2001 From: Brian Masney Date: Tue, 8 Sep 2026 13:47:19 -0400 Subject: driver: core: platform: add subsys_platform_driver() macro Add a new macro subsys_platform_driver() to eliminate some boilerplate code in drivers that need to register earlier in the boot at the subsys_initcall level. Signed-off-by: Brian Masney Assisted-by: Claude:claude-opus-4-8 Reviewed-by: Geert Uytterhoeven Reviewed-by: Abel Vesa Tested-by: Pankaj Patil Link: https://lore.kernel.org/r/20260908-subsys_initcall-v1-2-cbccf4cd4288@redhat.com Signed-off-by: Bjorn Andersson --- include/linux/platform_device.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'include/linux') diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 3d5bbcbae730..3bd0f1f0d870 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -344,6 +344,19 @@ static inline void platform_set_drvdata(struct platform_device *pdev, #define builtin_platform_driver(__platform_driver) \ builtin_driver(__platform_driver, platform_driver_register) +/* + * subsys_platform_driver() - Helper macro for drivers that don't do anything + * special in module init/exit but need to register earlier, at + * subsys_initcall level, when built in. This eliminates a lot of + * boilerplate. Each driver may only use this macro once, and calling it + * replaces module_init() and module_exit(). This is meant to be a parallel + * of module_platform_driver() above, but with the init call promoted to + * subsys_initcall() so built-in providers are available earlier during boot. + */ +#define subsys_platform_driver(__platform_driver) \ + subsys_driver(__platform_driver, platform_driver_register, \ + platform_driver_unregister) + /* module_platform_driver_probe() - Helper macro for drivers that don't do * anything special in module init/exit. This eliminates a lot of * boilerplate. Each module may only use this macro once, and @@ -376,6 +389,23 @@ static int __init __platform_driver##_init(void) \ } \ device_initcall(__platform_driver##_init); \ +/* + * subsys_platform_driver_probe() - Helper macro for drivers that don't do + * anything special in device init and have no exit, but need to register + * earlier, at subsys_initcall level. This eliminates some boilerplate. Each + * driver may only use this macro once, and using it replaces subsys_initcall. + * This is meant to be a parallel of builtin_platform_driver_probe above, but + * with the init call promoted to subsys_initcall so the provider is available + * earlier during boot. + */ +#define subsys_platform_driver_probe(__platform_driver, __platform_probe) \ +static int __init __platform_driver##_init(void) \ +{ \ + return platform_driver_probe(&(__platform_driver), \ + __platform_probe); \ +} \ +subsys_initcall(__platform_driver##_init) \ + #define platform_create_bundle(driver, probe, res, n_res, data, size) \ __platform_create_bundle(driver, probe, res, n_res, data, size, THIS_MODULE, KBUILD_MODNAME) extern struct platform_device *__platform_create_bundle( -- cgit v1.2.3