Publishing the driver

Once the driver feels good locally, spend ten extra minutes making it a crate other people will trust.

Cargo metadata

Start with the basics in Cargo.toml:

[package]
name = "tmp102"
version = "0.1.0"
edition = "2024"
description = "embedded-hal driver for the TMP102 I2C temperature sensor"
license = "MIT OR Apache-2.0"
repository = "https://github.com/OpenDevicePartnership/pico-de-gallo"
categories = ["embedded", "hardware-support", "no-std"]
keywords = ["tmp102", "temperature", "sensor", "i2c", "embedded-hal"]

If the crate is no_std, say so clearly in the README and crate docs. The generated crate resolves blocking versus async when it is scaffolded rather than behind a Cargo feature, so state which of the two surfaces it exposes right next to the first example.

docs.rs

If your docs need specific features enabled, tell docs.rs explicitly. Here the only optional features are defmt and hil, so turning everything on is the simplest correct answer:

[package.metadata.docs.rs]
all-features = true
rustdoc-args = ["--cfg", "docsrs"]

That avoids the common “works locally, missing items on docs.rs” trap.

README essentials

At minimum, include:

what the device is
which traits the crate implements or expects
a blocking example
an async example if you support one
feature flags (defmt, and the hil gate from the previous chapter)
wiring or address-selection notes for A0

For this driver, also mention that pico-de-gallo-hal is only used for examples and tests; it should stay in [dev-dependencies] so downstream users do not pay for it.

`defmt` support

The template already wired this up, and it spans two places that have to agree. Cargo.toml keeps the dependency optional and forwards the feature to the runtime:

[dependencies]
defmt = { version = "1", optional = true }

[features]
defmt = ["dep:defmt", "device-driver/defmt"]

The other half is the --rust-defmt-feature=defmt we passed to ddc. That is what puts #[cfg(feature = "defmt")] and #[cfg_attr(feature = "defmt", derive(defmt::Format))] in registers.rs. Rename the Cargo feature without regenerating and the generated code silently stops matching it.

Release hygiene

Three last bits of boring professionalism matter a lot:

keep a CHANGELOG.md
follow semver when you change the public API
commit src/registers.rs and let it into the package

Small drivers live a long time. A clean README, useful crate metadata, and predictable releases do more for adoption than one more clever type.

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