It would be great if there was an option to have a version of this (mod setting) that didn't require a crafting recipe. So it just burnt the fuel to make the fire and light.
As at present to make it "run" I have to put wood in the fuel slot and something in the input slot as well that just gets lost.

I intentionally wanted the camp fire to not just burn and shine, but to be able to actually do something, like cooking a fish.
Since version 2.0.0 the fire place became a furnace with its own crafting categories burning and cooking, so other mods will find it easier to add recipes that also work with this mod, which is already done by mods like cooked-fish and extreme-fishing.

Since every fuel get its own recipe in the burning category inserters wont find it hard to fill fuel in both slots, if you intent to just burn it ;)

This was for a streamer integration back then and I just scripted it's fuel and input items in the end 🙂

I'd like a version that only needs 1 input to work, too. Note that this can be accomplished while preserving the recipe idea by setting the energy_source to type "void". You lose the burner's flicker and smoke by doing this, but you're spawning a fire anyway.... You can define the emissions still with a void energy source, but fire does also have its own emissions, so you don't necessarily have to (though, admittedly, you define the per minute of emissions as 3, whereas a fire is 0.3, so the fire alone would create less pollution).

energy_source = {
    type = "void",
    emissions_per_minute = 3, -- optional as the fire itself does pollute
},

Edit: In hind sight, I'm realizing, too, that this will cause it to just consume whatever is put in there at one speed, regardless of what it is. Maybe you should just have a second entity? One for a simple fire, and one for actually cooking? Or, as the OP originally asked, a startup setting to allow the player to define it.