Re: [PATCH 01/31] swim: Assert strobe with stable outputs

[Finn Thain]

On Mon, 20 Jul 2026, Laurent Vivier wrote:

> Le 16/07/2026 à 12:02, Finn Thain a écrit :
> 
> > Keep the four phase pin directions set to output and hold their levels 
> > constant during LSTRB signalling.
> 
> Perhaps you can also add a short comment to describe the changes you 
> made to the defines.
> 

Can you clarify please? I think what you're asking is, shouldn't the PH3 
pin be an input when it's not being used for LSTRB signalling?

It would be nice if we had specs for the relevant FDD models, to show that 
no FDD ever drives the phase lines. Then I could write something more 
authoritative. I don't have that information but I do have the chip specs.

The swim3.c driver never sets phase pin direction because the SWIM3 chip 
doesn't implement that i.e. the four phase pins are permanently outputs. 
Similary, the programming model for the IWM chip offers no way to use 
phase lines as inputs, AFAICT. Same for the uPD72070 FDC chip.

I will add some of these observations to the commit log or the commentary 
in the source code if you think it would help.

Thanks for your review.