Re: [PATCH] extcon: usbc-tusb320: always rewrite REG9 to deassert INT_N

[Alvin Šipraga]

Hi Advait,

On Wed, Jul 29, 2026 at 04:38:52PM +0530, Advait Dhamorikar wrote:
> Hi Alvin,
> 
> Thanks for taking a look.
> 
> > Can you say a bit more about your hardware?
> 
> This is on an NXP i.MX8MP based board using a TUSB320 connected over I²C.
> The INT_N signal is connected to a GPIO configured as a level-low interrupt.

(I think we agree your patch is wrong, so I cut the rest of your reply)

[snip]

> I'm trying to understand why the hardware presents an asserted
> INT_N while REG9 reports no pending interrupt.

The INT_N signal is an open-drain output, so you need an external
pull-up resistor on the line. The TUSB320 will not drive it high when
there is no interrupt. Perhaps that's the problem?

If you have a pull-up resistor, check the behaviour when you hold the
TUSB320 in reset (use EN_N signal or power it off). If it's still low
then it's not the TUSB320 that's the problem.

If you have some kind of measuring tool (oscilloscope/etc.) it will be
more meaningful to probe the physical line than to listen to what Linux
or /proc/interrupts is telling you.

Hope that helps.

Kind regards,
Alvin