[PATCH net] mdio: mux: fix parsing mux registers outside of the PHY address range

[andrew@lunn.ch (Andrew Lunn)]

On Mon, Jul 10, 2017 at 02:35:23PM +0200, Martin Blumenstingl wrote:
> mdio_mux_init parses the child nodes of the MDIO mux. When using
> "mdio-mux-mmioreg" the child nodes are describing the register value
> that is written to switch between the MDIO busses.
> 
> The change which makes the error messages more verbose changed the
> parsing of the "reg" property from a simple of_property_read_u32 call
> to of_mdio_parse_addr. On a Khadas VIM (based on the Meson GXL SoC,
> which uses mdio-mux-mmioreg) this prevents registering the MDIO mux
> (because the "reg" values on the MDIO mux child nodes are 0x2009087f
> and 0xe40908ff) and leads to the following errors:
>   mdio-mux-mmioreg c883455c.eth-phy-mux: /soc/periphs at c8834000/eth-phy-mux/mdio at e40908ff PHY address -469169921 is too large
>   mdio-mux-mmioreg c883455c.eth-phy-mux: Error: Failed to find reg for child /soc/periphs at c8834000/eth-phy-mux/mdio at e40908ff
>   mdio-mux-mmioreg c883455c.eth-phy-mux: /soc/periphs at c8834000/eth-phy-mux/mdio at 2009087f PHY address 537462911 is too large
>   mdio-mux-mmioreg c883455c.eth-phy-mux: Error: Failed to find reg for child /soc/periphs at c8834000/eth-phy-mux/mdio at 2009087f
>   mdio-mux-mmioreg c883455c.eth-phy-mux: Error: No acceptable child buses found
>   mdio-mux-mmioreg c883455c.eth-phy-mux: failed to register mdio-mux bus /soc/periphs at c8834000/eth-phy-mux
> (as a result of that ethernet is not working, because the PHY which is
> connected through the mux' child MDIO bus, which is not being
> registered).
> 
> Fix this by reverting the change from of_mdio_parse_addr to
> of_mdio_parse_addr.

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

Yes, validating the reg property needs to be done separately in each
user of the generic mdio-mix code. The reg for the gpio mux must be <=
number of gpios, mmioreg must be somewhere within the address space,
bcm-iproc < 1024?

Jon, please feel free to add such code.

    Andrew