# gpiosim [](https://github.com/warthog618/gpiosim-rs/actions/workflows/rust.yml) [](https://github.com/warthog618/gpiosim-rs) [](https://crates.io/crates/gpiosim)  A Rust library for creating and controlling GPIO simulators for testing users of the Linux GPIO uAPI (both v1 and v2). The simulators are provided by the Linux [**gpio-sim**](https://www.kernel.org/doc/html/latest/admin-guide/gpio/gpio-sim.html) kernel module and require a recent kernel (5.19 or later) built with **CONFIG_GPIO_SIM**. Simulators contain one or more **Chip**s, each with a collection of lines being simulated. A **Builder** is responsible for constructing the **Sim** and taking it live. Configuring a simulator involves adding **Bank**s, representing the chip, to the builder. Once live, the **Chip** exposes lines which may be manipulated to drive the GPIO uAPI from the kernel side. For input lines, applying a pull using **Chip** pull methods controls the level of the simulated line. For output lines, the **Chip.get_level** method returns the level the simulated line is being driven to by userspace. For tests that only require lines on a single chip, the **Simpleton** provides a slightly simpler interface. Dropping the **Sim** deconstructs the simulator, removing the **gpio-sim** configuration and the corresponding gpiochips. Configuring a simulator involves *configfs*, and manipulating the chips once live involves *sysfs*, so root permissions are typically required to run a simulator. ## Example Usage Creating a simulator with two chips, with 8 and 42 lines respectively, each with several named lines and a hogged line: ```rust use gpiosim::{Bank, Direction, Level}; let sim = gpiosim::builder() .with_name("some unique name") .with_bank( Bank::new(8, "left") .name(3, "LED0") .name(5, "BUTTON1") .hog(2, "hogster", Direction::OutputLow) ) .with_bank( Bank::new(42, "right") .name(3, "BUTTON2") .name(4, "LED2") .hog(7, "hogster", Direction::OutputHigh), ) .live()?; let chips = sim.chips(); let c = &chips[0]; c.set_pull(5, Level::High); let level = c.get_level(3)?; ``` Use a **Simpleton** to create a single chip simulator with 12 lines, for where multiple chips or named lines are not required: ```rust let s = gpiosim::Simpleton::new(12); s.set_pull(5, Level::High); let level = s.get_level(3)?; ``` ## License Licensed under either of - Apache License, Version 2.0 ([LICENSE-APACHE](https://github.com/warthog618/gpiosim-rs/blob/master/LICENSES/Apache-2.0.txt) or ) - MIT license ([LICENSE-MIT](https://github.com/warthog618/gpiosim-rs/blob/master/LICENSES/MIT.txt) or ) at your option. ## Contribution Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.