linux-kernel - Re: [PATCH v1 2/2] usb: typec: tcpci: add vconn over current fault handling to maxim

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Message-ID: <ZWWd2AU+rJOWzzvx@kuha.fi.intel.com>
Date:   Tue, 28 Nov 2023 09:59:20 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     RD Babiera <rdbabiera@...gle.com>
Cc:     linux@...ck-us.net, gregkh@...uxfoundation.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        badhri@...gle.com
Subject: Re: [PATCH v1 2/2] usb: typec: tcpci: add vconn over current fault
 handling to maxim_core

On Tue, Nov 21, 2023 at 08:38:48PM +0000, RD Babiera wrote:
> Add TCPC_FAULT_STATUS_VCONN_OC constant and corresponding mask definition.
> Maxim TCPC is capable of detecting VConn over current faults, so add
> fault to alert mask. When a Vconn over current fault is triggered, put the
> port in an error recovery state via tcpm_port_error_recovery.
> 
> Signed-off-by: RD Babiera <rdbabiera@...gle.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/tcpm/tcpci_maxim_core.c | 20 +++++++++++++++++++-
>  include/linux/usb/tcpci.h                 |  5 ++++-
>  2 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpci_maxim_core.c b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
> index 9454b12a073c..7fb966fd639b 100644
> --- a/drivers/usb/typec/tcpm/tcpci_maxim_core.c
> +++ b/drivers/usb/typec/tcpm/tcpci_maxim_core.c
> @@ -92,11 +92,16 @@ static void max_tcpci_init_regs(struct max_tcpci_chip *chip)
>  		return;
>  	}
>  
> +	/* Vconn Over Current Protection */
> +	ret = max_tcpci_write8(chip, TCPC_FAULT_STATUS_MASK, TCPC_FAULT_STATUS_MASK_VCONN_OC);
> +	if (ret < 0)
> +		return;
> +
>  	alert_mask = TCPC_ALERT_TX_SUCCESS | TCPC_ALERT_TX_DISCARDED | TCPC_ALERT_TX_FAILED |
>  		TCPC_ALERT_RX_HARD_RST | TCPC_ALERT_RX_STATUS | TCPC_ALERT_CC_STATUS |
>  		TCPC_ALERT_VBUS_DISCNCT | TCPC_ALERT_RX_BUF_OVF | TCPC_ALERT_POWER_STATUS |
>  		/* Enable Extended alert for detecting Fast Role Swap Signal */
> -		TCPC_ALERT_EXTND | TCPC_ALERT_EXTENDED_STATUS;
> +		TCPC_ALERT_EXTND | TCPC_ALERT_EXTENDED_STATUS | TCPC_ALERT_FAULT;
>  
>  	ret = max_tcpci_write16(chip, TCPC_ALERT_MASK, alert_mask);
>  	if (ret < 0) {
> @@ -295,6 +300,19 @@ static irqreturn_t _max_tcpci_irq(struct max_tcpci_chip *chip, u16 status)
>  		}
>  	}
>  
> +	if (status & TCPC_ALERT_FAULT) {
> +		ret = max_tcpci_read8(chip, TCPC_FAULT_STATUS, &reg_status);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = max_tcpci_write8(chip, TCPC_FAULT_STATUS, reg_status);
> +		if (ret < 0)
> +			return ret;
> +
> +		if (reg_status & TCPC_FAULT_STATUS_VCONN_OC)
> +			tcpm_port_error_recovery(chip->port);
> +	}
> +
>  	if (status & TCPC_ALERT_EXTND) {
>  		ret = max_tcpci_read8(chip, TCPC_ALERT_EXTENDED, &reg_status);
>  		if (ret < 0)
> diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
> index 83376473ac76..467e8045e9f8 100644
> --- a/include/linux/usb/tcpci.h
> +++ b/include/linux/usb/tcpci.h
> @@ -36,7 +36,9 @@
>  
>  #define TCPC_ALERT_MASK			0x12
>  #define TCPC_POWER_STATUS_MASK		0x14
> -#define TCPC_FAULT_STATUS_MASK		0x15
> +
> +#define TCPC_FAULT_STATUS_MASK			0x15
> +#define TCPC_FAULT_STATUS_MASK_VCONN_OC		BIT(1)
>  
>  #define TCPC_EXTENDED_STATUS_MASK		0x16
>  #define TCPC_EXTENDED_STATUS_MASK_VSAFE0V	BIT(0)
> @@ -104,6 +106,7 @@
>  
>  #define TCPC_FAULT_STATUS		0x1f
>  #define TCPC_FAULT_STATUS_ALL_REG_RST_TO_DEFAULT BIT(7)
> +#define TCPC_FAULT_STATUS_VCONN_OC	BIT(1)
>  
>  #define TCPC_ALERT_EXTENDED		0x21
>  
> -- 
> 2.43.0.rc1.413.gea7ed67945-goog

-- 
heikki