09277e4fc9
Per the RMII specification, the REF_CLK is sourced from MAC to PHY or from an external source. But for TJA11xx PHYs, they support to output a 50MHz RMII reference clock on REF_CLK pin. Previously the "nxp,rmii-refclk-in" was added to indicate that in RMII mode, if this property present, REF_CLK is input to the PHY, otherwise it is output. This seems inappropriate now. Because according to the RMII specification, the REF_CLK is originally input, so there is no need to add an additional "nxp,rmii-refclk-in" property to declare that REF_CLK is input. Unfortunately, because the "nxp,rmii-refclk-in" property has been added for a while, and we cannot confirm which DTS use the TJA1100 and TJA1101 PHYs, changing it to switch polarity will cause an ABI break. But fortunately, this property is only valid for TJA1100 and TJA1101. For TJA1103/TJA1104/TJA1120/TJA1121 PHYs, this property is invalid because they use the nxp-c45-tja11xx driver, which is a different driver from TJA1100/TJA1101. Therefore, for PHYs using nxp-c45-tja11xx driver, add "nxp,rmii-refclk-out" property to support outputting RMII reference clock on REF_CLK pin. Signed-off-by: Wei Fang <wei.fang@nxp.com> Reviewed-by: Rob Herring (Arm) <robh@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.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 reStructuredText 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.