I am having some issues with a DP83826 PHY and therefore I want to read some configuration registers. I have used mdio-tool and mii-diag for it, but I just realized that I can only read the first 32 registers.
mii-diag -v (verbose) displays the first 32 registers (which might not be a coincidence) and if I use mdio-tool with an address beyond 0x1F, the address gets shifted to stay within the 0..1F range. I had a look at the code of mdio-tool and it does not limit the register address at all and I also hacked mii-diag -v a bit to get more than 32 registers and it also returns the first 32 registers again and again. So it seems that the limitation is somewhere else, but I have still not found where. I am now trying to find out if the API or the device driver is causing this issue.
I have also tried ethtool -d eth0 but it only dumps the GMAC and DMA registers.
How to read/writte PHY MII registers beyond 0x1F in Linux?