Re: [PATCH net-next 2/2] net: mdio: add a driver for PIC64-HPSC/HX MDIO controller

[Andrew Lunn <andrew@lunn.ch>]

> My idea is that if someone wants to use whatever is the hardware default
> or what was set by the bootloader, they have an option to do so. For that
> reason, I made the clock and the clock-frequency optional. This is
> something I can do without if you think it will homogenize better with new
> drivers.
> 
> Now I just realized that I can achieve this by just making the
> clock-frequency optional and not the clock.

It gets complicated pretty quickly, if you leave things open.

802.3 sets a maximum of 2.5Mhz. When this driver takes over the
hardware, and there is no hint from device tree what frequency to use,
but the hardware is configured to 50Mhz, what should it do? Trust the
bootloader? Or assume the bootloader or something else has messed it
up? Same goes for 1KHz?

Is the hardware default documented in the datasheet? Does it default
to 2.5Mhz?

>  - mdio-airoha.c: use 2.5MHz if not specified

I personally would do this. This keeps you in line with 802.3. Anybody
wanting to do anything else then uses clock-frequency, so the
intention is clearly documented.

	Andrew