Provide a configuration function for the host

[Zelzahn]

Some kind of host configuration function should be defined, some of the parameters that could be set: operating speed, target/controller, 10 bit/7 bit addressing, etc.

I see two possible locations:

• Inside the i2c resource: configure: func(options: options) (options would be a struct then)
• Provide it as part of an interface for a board world.

Personally, I prefer the second option. It seems to me that this follows the conclusions from https://github.com/WebAssembly/wasi-i2c/issues/2, and I favour (some kind of) uniformity across board worlds.

[sunfishcode]

I prefer the second option too. It keeps simple use cases very simple, and complex use cases can still add configuration mechanisms if they need to.

If there is a set of configuration options that are common across a sufficient set of boards, an option would be to define a common interface for configuration, perhaps something in roughly this shape:

interface i2c-config {
    use wasi:i2c/i2c@0.2.0-draft.{i2c, error-code};

     /// maybe like this? and more functions like this?
     set-speed: static func(bus: i2c, speed: u32) -> result<_, error-code>;

     /// or combine the options into a record?
     configure: static func(bus: i2c, options: options) -> result<_, error-code>;
}

That way, worlds could include it if it happens to fit their needs, rather than defining their one board-specific interfaces. I don't think we need to design this right now though; I just wanted to mention the option in case the need arises.