mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-08-31 12:52:29 -04:00
194e4ffd2e
Jonas Jelonek says:
====================
net: pse-pd: add Realtek PSE MCU support
This series adds a PSE-PD driver for the microcontroller (MCU) that
fronts the PSE silicon on a range of managed switches, together with its
DT binding.
Hardware model
==============
These boards do not expose the PSE chips to the host directly. A small
microcontroller sits on an I2C/SMBus or UART bus and manages one or more
PSE chips behind it; the host CPU only ever talks to that MCU, using a
fixed 12-byte request/response protocol with a trailing checksum. The
PSE silicon never appears on the bus.
Two generations of the protocol exist, both Realtek's: an older one on
boards with Broadcom PSE silicon (BCM59111, BCM59121) and a newer one
used with Realtek's own PSE silicon (RTL8238B, RTL8239, RTL8239C). They
diverge in opcode numbering and a few response layouts; the driver
abstracts that behind a per-dialect opcode table and parser hooks,
selected by the compatible. The specific PSE chip behind the MCU is
detected at runtime and only influences per-chip constants (power scaling
and the per-port cap).
The compatibles
===============
The protocol compatibles name two generations of the Realtek protocol,
with the I2C framing folded in:
realtek,pse-mcu-gen1 gen1, UART
realtek,pse-mcu-gen1-smbus gen1, I2C/SMBus
realtek,pse-mcu-gen2 gen2, UART
realtek,pse-mcu-gen2-smbus gen2, I2C/SMBus
realtek,pse-mcu-gen2-i2c gen2, raw I2C
and each board carries a device-specific compatible that falls back to one
of these, e.g.
compatible = "zyxel,xs1930-12hp-pse", "realtek,pse-mcu-gen2-smbus";
The naming is the part most likely to raise questions, so the reasoning up
front (the binding documents it too):
- The node describes the MCU together with its Realtek firmware, not a
PSE chip and not the microcontroller silicon. The PSE chips sit behind
the MCU, never appear on the bus, and are reported by the MCU and
detected at runtime; the microcontroller itself is a general-purpose
part (GigaDevice, Nuvoton, ...) that varies across boards. What is
fixed and Realtek's is the firmware and its host protocol - hence the
'realtek' prefix.
- gen1 and gen2 are two generations of that protocol, both Realtek's:
gen1 on older boards fronting Broadcom PSE silicon, gen2 the altered
protocol used once Realtek shipped their own PSE silicon. The
generation is fixed per board and is all the driver needs at DT-parse
time, so the compatible encodes it.
- On I2C the MCU firmware expects one of two framings - SMBus or raw
I2C - which is a genuine programming-model difference, so it is part
of the compatible ('-smbus' / '-i2c'). A UART attachment carries no
framing suffix; the transport is given structurally by the parent
'serial' node.
- Each board additionally carries a device-specific compatible that
falls back to the protocol one. The driver only ever binds on the
protocol compatible; the device-specific string keeps the binding
specific and reserves a place for a future per-board quirk without
having to retrofit device trees already deployed in the field.
Testing
=======
- Linksys LGS328MPCv2 (RTL8238B, I2C)
- Zyxel GS1900-10HP A1 (BCM59121, UART)
- Zyxel GS1900-10HP B1 (RTL8238B, UART)
- Zyxel GS1920-24HPv2 (BCM59121, SMBus)
- Zyxel XMG1915-10EP (RTL8239C, UART)
- Zyxel XS1930-12HP (RTL8239, SMBus)
====================
Link: https://patch.msgid.link/20260813222036.873930-1-jelonek.jonas@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst