Commit 59d4d06c authored by Badhri Jagan Sridharan's avatar Badhri Jagan Sridharan Committed by Greg Kroah-Hartman
Browse files

usb: typec: tcpm: Move TCPC to APPLY_RC state during PR_SWAP 



When vbus auto discharge is enabled, TCPCI based TCPC transitions
into Attached.SNK/Attached.SRC state. During PR_SWAP, TCPCI based
TCPC would disconnect when partner changes power roles. TCPC has
to be moved APPLY RC state during PR_SWAP. This is done by
ROLE_CONTROL.CC1 != ROLE_CONTROL.CC2 and
POWER_CONTROL.AutodischargeDisconnect is 0. Once the swap sequence
is done, AutoDischargeDisconnect is re-enabled.

Fixes: f321a02c ("usb: typec: tcpm: Implement enabling Auto Discharge disconnect support")
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarBadhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20210517192112.40934-3-badhri@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dea6f87e

drivers/usb/typec/tcpm/tcpm.c

+16 −0
Original line number Diff line number Diff line
@@ -789,6 +789,19 @@ static int tcpm_enable_auto_vbus_discharge(struct tcpm_port *port, bool enable) 
	return ret;

}



static void tcpm_apply_rc(struct tcpm_port *port)

{

	/*

	 * TCPCI: Move to APPLY_RC state to prevent disconnect during PR_SWAP

	 * when Vbus auto discharge on disconnect is enabled.

	 */

	if (port->tcpc->enable_auto_vbus_discharge && port->tcpc->apply_rc) {

		tcpm_log(port, "Apply_RC");

		port->tcpc->apply_rc(port->tcpc, port->cc_req, port->polarity);

		tcpm_enable_auto_vbus_discharge(port, false);

	}

}



/*

 * Determine RP value to set based on maximum current supported

 * by a port if configured as source.
@@ -4469,6 +4482,7 @@ static void run_state_machine(struct tcpm_port *port) 
		tcpm_set_state(port, ready_state(port), 0);

		break;

	case PR_SWAP_START:

		tcpm_apply_rc(port);

		if (port->pwr_role == TYPEC_SOURCE)

			tcpm_set_state(port, PR_SWAP_SRC_SNK_TRANSITION_OFF,

				       PD_T_SRC_TRANSITION);
@@ -4508,6 +4522,7 @@ static void run_state_machine(struct tcpm_port *port) 
		tcpm_set_state(port, ERROR_RECOVERY, PD_T_PS_SOURCE_ON_PRS);

		break;

	case PR_SWAP_SRC_SNK_SINK_ON:

		tcpm_enable_auto_vbus_discharge(port, true);

		/* Set the vbus disconnect threshold for implicit contract */

		tcpm_set_auto_vbus_discharge_threshold(port, TYPEC_PWR_MODE_USB, false, VSAFE5V);

		tcpm_set_state(port, SNK_STARTUP, 0);
@@ -4524,6 +4539,7 @@ static void run_state_machine(struct tcpm_port *port) 
			       PD_T_PS_SOURCE_OFF);

		break;

	case PR_SWAP_SNK_SRC_SOURCE_ON:

		tcpm_enable_auto_vbus_discharge(port, true);

		tcpm_set_cc(port, tcpm_rp_cc(port));

		tcpm_set_vbus(port, true);

		/*

include/linux/usb/tcpm.h

+4 −0
Original line number Diff line number Diff line
@@ -66,6 +66,8 @@ enum tcpm_transmit_type { 
 *		For example, some tcpcs may include BC1.2 charger detection

 *		and use that in this case.

 * @set_cc:	Called to set value of CC pins

 * @apply_rc:	Optional; Needed to move TCPCI based chipset to APPLY_RC state

 *		as stated by the TCPCI specification.

 * @get_cc:	Called to read current CC pin values

 * @set_polarity:

 *		Called to set polarity
@@ -120,6 +122,8 @@ struct tcpc_dev { 
	int (*get_vbus)(struct tcpc_dev *dev);

	int (*get_current_limit)(struct tcpc_dev *dev);

	int (*set_cc)(struct tcpc_dev *dev, enum typec_cc_status cc);

	int (*apply_rc)(struct tcpc_dev *dev, enum typec_cc_status cc,

			enum typec_cc_polarity polarity);

	int (*get_cc)(struct tcpc_dev *dev, enum typec_cc_status *cc1,

		      enum typec_cc_status *cc2);

	int (*set_polarity)(struct tcpc_dev *dev,