Re: [PATCH] usb: typec: tcpci: add alert.fault handling

On 26-08-05, Heikki Krogerus wrote:
> On Fri, Jul 31, 2026 at 10:34:59AM +0200, Marco Felsch wrote:
> > Add minimal handling to clear the ALERT.Fault bit which may be set in
> > case of an over-current or over-voltage detection. At the moment only
> > the IRQ clear support is added since the TCPC Spec mentions that the
> > handling of such events is vendor specific.
> > 
> > Signed-off-by: Marco Felsch <[email protected]>
> > ---
> >  drivers/usb/typec/tcpm/tcpci.c | 16 +++++++++++++++-
> >  1 file changed, 15 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> > index a56e31b20c21..d2d5bf7ca618 100644
> > --- a/drivers/usb/typec/tcpm/tcpci.c
> > +++ b/drivers/usb/typec/tcpm/tcpci.c
> > @@ -692,7 +692,8 @@ static int tcpci_init(struct tcpc_dev *tcpc)
> >  
> >  	reg = TCPC_ALERT_TX_SUCCESS | TCPC_ALERT_TX_FAILED |
> >  		TCPC_ALERT_TX_DISCARDED | TCPC_ALERT_RX_STATUS |
> > -		TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_CC_STATUS;
> > +		TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_CC_STATUS |
> > +		TCPC_ALERT_FAULT;
> >  	if (tcpci->controls_vbus)
> >  		reg |= TCPC_ALERT_POWER_STATUS;
> >  	/* Enable VSAFE0V status interrupt when detecting VSAFE0V is supported */
> > @@ -720,6 +721,19 @@ irqreturn_t tcpci_irq(struct tcpci *tcpci)
> >  	irq_ret = status & tcpci->alert_mask;
> >  
> >  process_status:
> > +	/*
> > +	 * Handle nested fault before clearing the alert status to not
> > +	 * re-trigger a fault alert immediately again.
> > +	 */
> 
> Shouldn't that explanation in the comment be also in the commit
> message? That sounds like the "why" part to me.

I don't think so, it's just a comment for $dev that this ordering is
important. The commit message clearly states that an over-current or
over-voltage may trigger this.

Regards,
  Marco

> > +	if (status & TCPC_ALERT_FAULT) {
> > +		unsigned int fault;
> > +
> > +		/* TODO: Add a proper over-current and over-voltage handling */
> > +		ret = regmap_read(tcpci->regmap, TCPC_FAULT_STATUS, &fault);
> > +		if (!ret)
> > +			regmap_write(tcpci->regmap, TCPC_FAULT_STATUS, fault);
> > +	}
> > +
> >  	/*
> >  	 * Clear alert status for everything except RX_STATUS, which shouldn't
> >  	 * be cleared until we have successfully retrieved message.
> > -- 
> > 2.47.3
> 
> -- 
> heikki
> 

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