## Overview
This PR addresses the severe memory leak and performance issues observed in `mai2`, while also introducing improvements to the touch emulation logic.
## Root Cause Analysis
As discussed previously, the root cause of the `mai2` memory leak is not a global `segatools` buffer bug. Instead, the game aggressively spams overlapped empty reads specifically on the `LED 15070` UART. On real hardware, the serial driver naturally throttles this. Under emulation, without a throttle, it hits approximately **260kHz of empty async reads**, which causes the memory usage to explode.
## The Fix
Instead of introducing complex locking mechanisms and condition variables globally in `uart.c`, this PR applies a targeted fix:
* Added a local `Sleep(1)` directly in `common/board/led15070.c` to rate-limit empty reads on the LED path.
* Because this is isolated to LED communications, it completely resolves the memory leak without introducing any lag, livelocks, or overhead to other critical inputs.
## Additional Changes in this PR
Alongside the memory leak fix, this PR includes a few touch-related improvements (as touch emulation was reviewed during the debugging process):
* Enhanced touch input handling and improved auto-scan state management.
* Implemented IOCTL handling for touch input to properly manage communication status.
## Testing
* **mai2:** Tested successfully on multiple machines. The memory leak is completely gone, and the game runs smoothly.
* **chusan:** Tested to ensure no regressions. Sliders and inputs work flawlessly without the lag.
Reviewed-on: https://gitea.tendokyu.moe/TeamTofuShop/segatools/pulls/101
Co-authored-by: Gl0w1amp <gl0w1amp@noreply.gitea.tendokyu.moe>
Co-committed-by: Gl0w1amp <gl0w1amp@noreply.gitea.tendokyu.moe>
## Summary
- feat(io4): implement PWM/GPIO support for Billboard and Code Reader lights
- feat(mai2io): expose LED control APIs to support new io4 features
- fix(led15070): correct multi-LED color logic and add fade support
## Description
**io4 & mai2io Updates**
Introduced PWM control and GPIO write support in `io4`. These additions allow `mai2io` to properly drive the **Billboard LEDs** and **Code Reader / Player Camera lights**. The APIs have been exposed through `mai2hook` to facilitate scriptable control of these peripherals.
**led15070 Improvements**
Fixed an issue with the multi-LED color changing logic in the `led15070` driver. This ensures correct color output sequence and includes improvements for fade calculation.
Reviewed-on: https://gitea.tendokyu.moe/TeamTofuShop/segatools/pulls/89
Co-authored-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>
Co-committed-by: グローランプ <130208311+Gl0w1amp@users.noreply.github.com>
Gl0w1amp