Re: [net-next 4/4] net: ftgmac100: add RGMII delay for AST2600

[Russell King (Oracle)]

On Mon, Mar 17, 2025 at 09:53:33AM +0100, Maxime Chevallier wrote:
> So this goes completely against the naming of the property. It has the
> -ps suffix, so you would expect to have picoseconds values passed, and
> not an arbiraty index.
> 
> Take a look at other drivers, you should accept picseconds values from
> these properties, then compute the relevant index in the driver. That
> index should be something internal to your driver.
> 
> An example here :
> 
> https://elixir.bootlin.com/linux/v6.14-rc6/source/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x_rgmii.c#L51

Another example would be drivers/net/phy/adin.c::adin_get_reg_value()
and associated functions - these lookup a DT property and then look
that up in a table to convert it to a register value.

I suspect that's something which could become generic, as I suspect
most hardware isn't going to accept a picosecond value, but be a
choice of N different options.

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