Re: [PATCH v3 6/7] dt-bindings: net: dsa: mediatek,mt7530: add econet,en751221

[Caleb James DeLisle <cjd@cjdns.fr>]

On 28/10/2026 03:26, Andrew Lunn wrote:
> On Wed, Oct 28, 2026 at 01:13:16AM +0000, Caleb James DeLisle wrote:
>> The EcoNet EN751221 MIPS SoC integrates an MT7530 switch memory-mapped
>> in the SoC register space. It is similar to the econet,en7528-switch
>> except that ports 0..3 are 10/100 only, port 4 has a gigabit PHY, and
>> port 5 has no PHY, but is in some implementations connected to a
>> downstream MT7530 multi-chip module via a TRGMII link.
>>
>> The downstream MT7530 is similar to the MT7621 multi-chip module and
>> has all gigabit ports.
>>
>> Add the econet,en751221-switch compatible with the same constraints as
>> the other built-in switches and also add the econet,en751221-gswitch
>> multi-chip-module switch whose port 6 is configured as a DSA link port.
> Is there a use case of the econet,en751221-switch not in pass through
> mode? This is where you could have a different dsa_switch_ops
> structure, which probably makes the changes less invasive.
>
> Even if there is a use case for not pass through, you can still look
> for the property in probe, and decide which of two different
> dsa_switch_ops to pass to dsa_register_switch.


I think this was pretty much answered in my reply to your patch 3 
review. Without insider knowledge, my understanding is EN751221 is a 
common die, and it's packaged in a variety of different EN751x (DSL) and 
EN752x (Fiber) chip modules. The die has a switch with 3x 10/100 ports 
and 1x gigabit port. Chips with a 'G' in the name (EN7513G, EN7526G that 
I know) have the MCM switch and use the on-die switch as a passthrough. 
So yes, in short there are real (and quite popular) devices with both 
MCM and non-MCM implementations.


Thanks,

Caleb


>
> 	   Andrew