Learn how to release GPIO pins from Linux on i.MX8MP so the Cortex-M7 can use them safely for control and interrupts without A53 conflicts.
On the i.MX8MP platform, the Cortex-M7 (M-Core) and Cortex-A53 (Linux) often compete for GPIO resources. By default, Linux owns the pinmux and GPIO controllers, which can prevent the M-Core from using pins reliably—especially for interrupt inputs.
To give the M-Core full control, the A-Core must first “release” those pins in the device tree: ✅ Remove the pinmux configuration for the target GPIO ✅ Comment out all Linux device nodes that reference it ✅ For interrupt use on GPIO2/3/4 groups, disable the entire GPIO controller so Linux no longer registers it
This clean separation avoids resource conflicts, ensures stable interrupts, and allows the M-Core to operate with real-time determinism.
A small device tree change, but a big step toward robust heterogeneous multi-core design on i.MX8MP.
