linux-kernel - [PATCH v1] usb: typec: tcpm: Disregard vbus off while in PR_SWAP_SNK_SRC_SOURCE

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Message-Id: <20201125020703.1604979-1-badhri@google.com>
Date:   Tue, 24 Nov 2020 18:07:03 -0800
From:   Badhri Jagan Sridharan <badhri@...gle.com>
To:     Guenter Roeck <linux@...ck-us.net>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Badhri Jagan Sridharan <badhri@...gle.com>
Subject: [PATCH v1] usb: typec: tcpm: Disregard vbus off while in PR_SWAP_SNK_SRC_SOURCE_ON

During PR_SWAP sequence, when TCPM is waiting in PR_SWAP_SNK_SRC_SOURCE_ON
for the vbus source to ramp up, TCPM would prematurely exit
PR_SWAP_SNK_SRC_SOURCE_ON and transition to SNK_UNATTACHED state when a
vbus off notification is received. This should not be the case as vbus
can still be off while in PR_SWAP_SNK_SRC_SOURCE_ON and the vbus source
has PD_T_NEWSRC to ramp up.

Signed-off-by: Badhri Jagan Sridharan <badhri@...gle.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 4aac0efdb720..277b9d4d9c84 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4218,6 +4218,14 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port)
 		/* Do nothing, expected */
 		break;
 
+	case PR_SWAP_SNK_SRC_SOURCE_ON:
+		/*
+		 * Do nothing when vbus off notification is received.
+		 * TCPM can wait for PD_T_NEWSRC in PR_SWAP_SNK_SRC_SOURCE_ON
+		 * for the vbus source to ramp up.
+		 */
+		break;
+
 	case PORT_RESET_WAIT_OFF:
 		tcpm_set_state(port, tcpm_default_state(port), 0);
 		break;
-- 
2.29.2.454.gaff20da3a2-goog