6937602ed3
The Broadcom BCM54140 is a Quad SGMII/QSGMII Copper/Fiber Gigabit Ethernet transceiver. This also adds support for tunables to set and get downshift and energy detect auto power-down. The PHY has four ports and each port has its own PHY address. There are per-port registers as well as global registers. Unfortunately, the global registers can only be accessed by reading and writing from/to the PHY address of the first port. Further, there is no way to find out what port you actually are by just reading the per-port registers. We therefore, have to scan the bus on the PHY probe to determine the port and thus what address we need to access the global registers. Signed-off-by: Michael Walle <michael@walle.cc> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.