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

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

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 <m.felsch@pengutronix.de>
> ---
>  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.

> +	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