Re: [PATCH net-next v15 12/13] net: mdio: realtek-rtl9300: Add support for RTL839x

[Andrew Lunn <andrew@lunn.ch>]

On Mon, Aug 31, 2026 at 04:34:38PM +0200, Markus Stockhausen wrote:
61;8001;1c> The MDIO driver has been prepared for multiple device support. Add all
> required bits for the RTL839x (aka cypress) series. This is straightforward
> but some things are worth mentioning.
> 
> - The device has a lot in common with the RTL931x series. It has 8192
>   (Realtek) pages and 7 MMIO registers.
> - There are two SMI buses for 1G PHYs. Neither the bus nor address map
>   registers exist.
> - The hardware has not much to configure. So the setup_controller()
>   function is not needed.
> - The bit specific registers (polling & port_mask) are 2x32 bit wide. The
>   ports 0..31 got to <reg> and the ports 32..51 go to <reg+4>.
> - C22 read/write functions must be called with PARK_PAGE = 0. Keep code
>   clean and avoid setting it to zero, matching the behavior of the RTL9310
>   logic.
> - As per SDK the broadcast register allows to write to multiple ports
>   at the same time. Unlike RTL9310 where this is filled with a bit mask
>   for the current port RTL8390 does not use it for normal reads/writes.
>   It is simply set to 0 like the SDK does.
> - The SDK fills the EXT_PAGE register with 0x1ff for C22 access and with
>   0x0 for C45 access. The reason for this is currently unknown and a
>   meaningful name can not be given. Align the driver coding with the
>   RTL9300_PHY_CTRL_PARK_PAGE settings and simply fill the hardcoded value.
> 
> Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew