1b0a83ac04
Some PHYs (for example the SMSC LAN8710/LAN8720) doesn't allow turning
the refclk on and off again during operation (according to their
datasheet). Nonetheless exactly this behaviour was introduced for power
saving reasons by commit e8fcfcd5684a ("net: fec: optimize the clock management to save power").
Therefore add support for the phy_reset_after_clk_enable function from
phylib to mitigate this issue.
Generally speaking this issue is only relevant if the ref clk for the
PHY is generated by the SoC and therefore the PHY is configured to
"REF_CLK In Mode". In our specific case (PCB) this problem does occur at
about every 10th to 50th POR of an LAN8710 connected to an i.MX6SOLO
SoC. The typical symptom of this problem is a "swinging" ethernet link.
Similar issues were reported by users of the NXP forum:
https://community.nxp.com/thread/389902
https://community.nxp.com/message/309354
With this patch applied the issue didn't occur for at least a few
hundret PORs of our board.
Fixes: e8fcfcd5684a ("net: fec: optimize the clock management to save power")
Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.