mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-05 17:03:47 -04:00
be969b7cfb
HiFive unleashed A00 board has VSC8541-01 ethernet phy, this device is identified as a Revision B device as described in device identification registers. In order to use this phy in the unmanaged mode, it requires a specific reset sequence of logical 0-1-0-1 transition on the NRESET pin as documented here [1]. Currently, the bootloader (fsbl or u-boot-spl) takes care of the phy reset. If due to some reason the phy device hasn't received the reset by the prior stages before the linux macb driver comes into the picture, the MACB mii bus gets probed but the mdio scan fails and is not even able to read the phy ID registers. It gives an error message: "libphy: MACB_mii_bus: probed mdio_bus 10090000.ethernet-ffffffff: MDIO device at address 0 is missing." Thus adding the device OUI (Organizationally Unique Identifier) to the phy device node helps to probe the phy device. [1]: VSC8541-01 datasheet: https://www.mouser.com/ds/2/523/Microsemi_VSC8541-01_Datasheet_10496_V40-1148034.pdf Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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.