cu-linux-resources

Linux/host resource bundle for serial, I2C, and GPIO peripherals.

Provider

Use cu_linux_resources::LinuxResources in copperconfig.ron.

resources: [
  (
    id: "linux",
    provider: "cu_linux_resources::LinuxResources",
    config: {
      "serial3_dev": "/dev/ttyUSB0",
      "serial3_baudrate": 420000,
      "serial3_parity": "none",
      "serial3_stopbits": 1,
      "serial3_timeout_ms": 100,
      "i2c1_dev": "/dev/i2c-1",
      "gpio0_pin": 23,
      "gpio0_direction": "output",
      "gpio0_bias": "pull_up",
      "gpio0_initial_level": "high",
      "gpio1_pin": 24,
      "gpio1_direction": "input",
      "gpio1_bias": "pull_down",
    },
  ),
],

Fixed Resource Slots

LinuxResources exposes embedded-style fixed slots:

Serial: serial0, serial1, serial2, serial3, serial4, serial5
I2C: i2c0, i2c1, i2c2
GPIO: gpio0, gpio1, gpio2, gpio3, gpio4, gpio5

Bind tasks/bridges to these slots via <bundle>.<slot> (for example linux.serial3).

Config Keys

Serial

Per-slot keys are serial0..serial5. Each slot maps to a fixed resource id:

serial0_* -> serial0
serial1_* -> serial1
serial2_* -> serial2
serial3_* -> serial3
serial4_* -> serial4
serial5_* -> serial5

Note: Serial and I2C slots are only initialized when explicitly configured. Unconfigured slots are skipped.

Supported keys per serial slot serialN:

serialN_dev (string)
serialN_baudrate (u32, default 115200)
serialN_parity (string: none, odd, even; default none)
serialN_stopbits (u8: 1 or 2; default 1)
serialN_timeout_ms (u64, default 50)

I2C

i2c0_dev (no default - must be configured)
i2c1_dev (no default - must be configured)
i2c2_dev (no default - must be configured)

GPIO

Each slot gpioN (N=0..5) is enabled only when gpioN_pin is set.

Per-slot keys:

gpioN_pin (u8, required when slot is configured)
gpioN_direction (string, required when slot is configured): input or output
gpioN_bias (string, optional, default off): off, pull_up, pull_down
gpioN_initial_level (string, optional, output-only): low, high

Direction determines the concrete resource type:

direction: "input" registers LinuxInputPin
direction: "output" registers LinuxOutputPin (output mode with optional pull bias)

If gpioN_initial_level is omitted for an output slot, initialization preserves the current GPIO output level.

Validation is strict for GPIO config:

Invalid direction, bias, or initial_level values fail bundle build.
Setting gpioN_initial_level on an input pin fails bundle build.
Setting gpioN_direction/bias/initial_level without gpioN_pin fails bundle build.

Exclusive Wrapper

cu_linux_resources::Exclusive<T> is the bundle-layer wrapper for resources that are logically single-owner but must satisfy Sync for ResourceManager::add_owned.

Keeping that adaptation in the resource layer avoids consumer-side wrappers in bridges/tasks.

cu-linux-resources 0.15.0