Add support for FC14 SPI (Untested) and FC15 I2C

[sukomath]

• Adding [RFC] Add support for flexcomm14 and 15 #235 to enable FC14 and FC15
• Changes in I2C module to support FC15 I2C master

@tullom FYI

[sukomath]

@felipebalbi @jerrysxie @DM777-ms Adding FC15 support changes. For the review comment from #235 - are we planning to adding this in PAC? Let me know if there is anything related to this review comment that needs to be addressed in this PR.

[Copilot]

Pull Request Overview

This PR adds support for FC14 SPI (untested) and FC15 I2C by introducing new abstractions for handling FC15 pins and extending flexcomm implementations. Key changes include:

• Adding a new trait and struct (FC15Pin) in src/iopctl.rs with its corresponding macro to support FC15 pin configuration.
• Introducing new flexcomm implementations for FLEXCOMM14 (SPI) and FLEXCOMM15 (I2C), updating clock selection and peripheral enable code.
• Adjusting the I2C instance mapping and count to incorporate FLEXCOMM15.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/iopctl.rs	Added new FC15 pin support via trait ToFC15Pin, FC15Pin struct, and a dedicated macro.
src/flexcomm.rs	Extended flexcomm support to include new implementations for FLEXCOMM14 and FLEXCOMM15 with updated clock setup.
src/i2c/mod.rs	Modified I2C instance handling to map FLEXCOMM15 to a new index and update the instance count.
src/chips/mimxrt633s.rs	Updated peripheral list to include FC15 I2C pins.
src/chips/mimxrt685s.rs	Updated peripheral list to include FC15 I2C pins.

Comments suppressed due to low confidence (3)

src/iopctl.rs:416

• [nitpick] The set_function method in the FC15Pin implementation intentionally ignores the provided function value. Consider adding or expanding the inline documentation to clarify that FC15 pins have fixed functionality and thus do not support runtime function configuration.

fn set_function(&self, _function: Function) -> &Self {

src/flexcomm.rs:115

• FLEXCOMM14 SPI support is marked as untested. Please ensure that adequate tests are added to validate its functionality before this feature is used in production.

// TODO: FLEXCOMM 14 is untested. Enable SPI support on FLEXCOMM14

src/i2c/mod.rs:105

• [nitpick] Mapping FLEXCOMM15 to index 8 uses a magic number; consider documenting the rationale behind this mapping or replacing it with a named constant to enhance code clarity.

if $n == 15 { info_index = 8; }