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Explore the complexities of GPIO resource management in Linux kernel systems through this 19-minute conference talk that examines the fundamental contradiction between the exclusive nature of GPIO consumer APIs and real-world hardware designs where multiple devices share the same GPIO pins. Learn about the challenges kernel engineers face when device-tree models reference the same GPIO across different device nodes, creating conflicts between drivers that need to request the same line. Discover existing infrastructure solutions like the reset-gpios property handled by reset core, and understand why current workarounds involving driver "fights" over GPIOs lack proper concurrency protection. Examine complex scenarios such as the PERST# signal in PCI systems where logical behavior requires coordinated control across multiple users. Gain insights into the detailed problems, existing solutions, ongoing development efforts, and the limitations of C code solutions using device-tree information before requiring hardware-specific quirks.
