Re: [PATCH v5 10/10] net: stmmac: dwmac-sun8i: Handle integrated/external MDIOs
From: Andrew Lunn <andrew@lunn.ch>
Date: 2017-09-08 14:17:48
Also in:
linux-arm-kernel, linux-devicetree, lkml
quoted
Do you know why the reset times out/fails?Because there are nothing connected to it.
That should not be an issue. A read should just return 0xffff. And it
should return 0xffff fast. The timing of the MDIO protocol is fixed. A
read or a write takes a fixed number of cycles, independent of if
there is a device there or not. The bus data line has a pullup, so if
you try to access a missing device, you automatically read 0xffff.
Andrew