linux-kernel - Re: [PATCH v1] usb: typec: tcpm: Ignore CC and vbus changes in PORT

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Message-ID: <20200414120407.GE2828150@kuha.fi.intel.com>
Date:   Tue, 14 Apr 2020 15:04:07 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Badhri Jagan Sridharan <badhri@...gle.com>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] usb: typec: tcpm: Ignore CC and vbus changes in
 PORT_RESET change

On Thu, Apr 02, 2020 at 02:59:47PM -0700, Badhri Jagan Sridharan wrote:
> After PORT_RESET, the port is set to the appropriate
> default_state. Ignore processing CC changes here as this
> could cause the port to be switched into sink states
> by default.
> 
> echo source > /sys/class/typec/port0/port_type
> 
> Before:
> [  154.528547] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms
> [  154.528560] CC1: 0 -> 0, CC2: 3 -> 0 [state PORT_RESET, polarity 0, disconnected]
> [  154.528564] state change PORT_RESET -> SNK_UNATTACHED
> 
> After:
> [  151.068814] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev3 NONE_AMS]
> [  151.072440] CC1: 3 -> 0, CC2: 0 -> 0 [state PORT_RESET, polarity 0, disconnected]
> [  151.172117] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]
> [  151.172136] pending state change PORT_RESET_WAIT_OFF -> SRC_UNATTACHED @ 870 ms [rev3 NONE_AMS]
> [  152.060106] state change PORT_RESET_WAIT_OFF -> SRC_UNATTACHED [delayed 870 ms]
> [  152.060118] Start toggling

Guenter, can you take a look at this?

> Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index de3576e6530ab2..82b19ebd7838e0 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -3794,6 +3794,14 @@ static void _tcpm_cc_change(struct tcpm_port *port, enum typec_cc_status cc1,
>  		 */
>  		break;
>  
> +	case PORT_RESET:
> +	case PORT_RESET_WAIT_OFF:
> +		/*
> +		 * State set back to default mode once the timer completes.
> +		 * Ignore CC changes here.
> +		 */
> +		break;
> +
>  	default:
>  		if (tcpm_port_is_disconnected(port))
>  			tcpm_set_state(port, unattached_state(port), 0);
> @@ -3855,6 +3863,15 @@ static void _tcpm_pd_vbus_on(struct tcpm_port *port)
>  	case SRC_TRY_DEBOUNCE:
>  		/* Do nothing, waiting for sink detection */
>  		break;
> +
> +	case PORT_RESET:
> +	case PORT_RESET_WAIT_OFF:
> +		/*
> +		 * State set back to default mode once the timer completes.
> +		 * Ignore vbus changes here.
> +		 */
> +		break;
> +
>  	default:
>  		break;
>  	}
> @@ -3908,10 +3925,19 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
>  	case PORT_RESET_WAIT_OFF:
>  		tcpm_set_state(port, tcpm_default_state(port), 0);
>  		break;
> +
>  	case SRC_TRY_WAIT:
>  	case SRC_TRY_DEBOUNCE:
>  		/* Do nothing, waiting for sink detection */
>  		break;
> +
> +	case PORT_RESET:
> +		/*
> +		 * State set back to default mode once the timer completes.
> +		 * Ignore vbus changes here.
> +		 */
> +		break;
> +
>  	default:
>  		if (port->pwr_role == TYPEC_SINK &&
>  		    port->attached)
> -- 
> 2.26.0.292.g33ef6b2f38-goog

thanks,

-- 
heikki