How to determine dependencies when writing a Kconfig file

When writing a Kconfig file, the dependencies of a configuration item (config) depend on the conditions under which you want it to be available. The determination of dependencies can be based on the following considerations:

1. Hardware requirements: If your code is written for a specific piece of hardware, then support for that hardware may be your dependency. For example, if your code is a device driver, then you may need to rely on the corresponding device number ( depend on HAS_IOMEM) or BUS support ( depend on SPI_MASTER).

2. Functional requirements: If your code depends on a feature or module of the kernel, then this feature or module may be your dependency. For example, if your code needs to use the kernel's SPI framework, then you may need to rely on it SPI.

3. Other configuration options: Your code may depend on other configuration options, especially those that affect overall system behavior. For example, if your code only DEBUG_KERNELmakes sense when is turned on, then you can rely on DEBUG_KERNEL.

depends onYou can specify dependencies by adding lines before your configuration options . if ...You can also specify dependencies by adding to the option line , which is more convenient for a group of related options.

Note that you need to ensure that all dependencies have been defined elsewhere before use, otherwise your configuration options may not work properly. In addition, the dependency relationship may be more complex, and may require logical operations such as AND( &&), OR( ||), NOT( !), etc., or may depend on the value of the configuration item. When determining dependencies, you need to think carefully based on the actual needs of your code.

If you're not sure which items your code should depend on, you can consult the documentation for the relevant hardware and functionality, or refer to other similar code and configuration items. You can also try adding some dependencies and see if they meet your needs.