Re: [PATCH v2] usb: typec: fusb302: Switch to threaded IRQ handler

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Mar 17, 2026 at 08:30:15PM +0400, Alexey Charkov wrote:
> FUSB302 fails to probe with -EINVAL if its interrupt line is connected via
> an I2C GPIO expander, such as TI TCA6416.
> 
> Switch the interrupt handler to a threaded one, which also works behind
> such GPIO expanders.
> 
> Cc: stable@vger.kernel.org
> Fixes: 309b6341d557 ("usb: typec: fusb302: Revert incorrect threaded irq fix")
> Signed-off-by: Alexey Charkov <alchark@flipper.net>
> ---
> Changes in v2:
> - Re-added the IRQF_ONESHOT flag to the request_threaded_irq() call
>   (thanks Hans de Goede and Sebastian Andrzej Siewior)
> - Link to v1: https://lore.kernel.org/r/20260311-fusb302-irq-v1-1-7e7105706629@flipper.net
> ---
>  drivers/usb/typec/tcpm/fusb302.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index ce7069fb4be6..889c4c29c1b8 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -1764,8 +1764,9 @@ static int fusb302_probe(struct i2c_client *client)
>  		goto destroy_workqueue;
>  	}
>  
> -	ret = request_irq(chip->gpio_int_n_irq, fusb302_irq_intn,
> -			  IRQF_TRIGGER_LOW, "fsc_interrupt_int_n", chip);
> +	ret = request_threaded_irq(chip->gpio_int_n_irq, NULL, fusb302_irq_intn,
> +				   IRQF_ONESHOT | IRQF_TRIGGER_LOW,
> +				   "fsc_interrupt_int_n", chip);
>  	if (ret < 0) {
>  		dev_err(dev, "cannot request IRQ for GPIO Int_N, ret=%d", ret);
>  		goto tcpm_unregister_port;
> 

I'll take this, but the testing systems rightly point out that
chip->gpio_int_n_irq may NOT be initialized before this call is made in
some situations, so this whole irq handler might never be set up.

I know your change didn't cause that logic bug to show up, but can you
send a patch to fix that, as you have the ability to test these types of
changes?

thanks,

greg k-h