Power Sequencing for Enumerable Busses - What's Still Missing From the Device Tree...
summary
Enumerates real gaps: SDIO power-sequence bindings exist but are now deprecated, USB host Type-A power is described in DT yet USB Type-A VBUS binding unsupported so many platforms use ad‑hoc regulator or always‑on hacks, PCIe slot bindings grab regulators but PCIe slot bindings violate spec causing link‑training failures until the deferred power framework runs (6.11/6.15), and MDIO reset/clock/supply handling is inconsistent requiring resets under the bus node to avoid missed PHY IDs.
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chapters (7)
- 0:00Introduction and speaker background
- 1:27SDIO power sequencing issues
- 2:52USB connector bindings problems
- 5:23PCIe power sequencing challenges
- 8:15MDIO bus power sequencing flaws
- 12:08Recap and proposed solutions
- 18:56Q&A and closing remarks
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