With some chargers, vbus might momentarily raise above VSAFE5V and fall back to 0V before tcpm gets to read port->tcpc->get_vbus. This will report a VBUS off event causing TCPM to transition to SNK_UNATTACHED where it should be waiting in either SNK_ATTACH_WAIT or SNK_DEBOUNCED state. This patch makes TCPM avoid vbus off events while in SNK_ATTACH_WAIT or SNK_DEBOUNCED state.
Stub from the spec: "4.5.2.2.4.2 Exiting from AttachWait.SNK State A Sink shall transition to Unattached.SNK when the state of both the CC1 and CC2 pins is SNK.Open for at least tPDDebounce. A DRP shall transition to Unattached.SRC when the state of both the CC1 and CC2 pins is SNK.Open for at least tPDDebounce."
[23.194131] CC1: 0 -> 0, CC2: 0 -> 5 [state SNK_UNATTACHED, polarity 0, connected] [23.201777] state change SNK_UNATTACHED -> SNK_ATTACH_WAIT [rev3 NONE_AMS] [23.209949] pending state change SNK_ATTACH_WAIT -> SNK_DEBOUNCED @ 170 ms [rev3 NONE_AMS] [23.300579] VBUS off [23.300668] state change SNK_ATTACH_WAIT -> SNK_UNATTACHED [rev3 NONE_AMS] [23.301014] VBUS VSAFE0V [23.301111] Start toggling
Fixes: f0690a25a140b8 ("staging: typec: USB Type-C Port Manager (tcpm)") Cc: stable@vger.kernel.org Signed-off-by: Badhri Jagan Sridharan badhri@google.com Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Reviewed-by: Guenter Roeck linux@roeck-us.net --- Changes since v1: - Fix typos stated by Guenter Roeck. Changes since v2: - Added reviewed/acked-by tags --- drivers/usb/typec/tcpm/tcpm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 59d4fa2443f2..3bf79f52bd34 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -5156,7 +5156,8 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port) case SNK_TRYWAIT_DEBOUNCE: break; case SNK_ATTACH_WAIT: - tcpm_set_state(port, SNK_UNATTACHED, 0); + case SNK_DEBOUNCED: + /* Do nothing, as TCPM is still waiting for vbus to reach VSAFE5V to connect */ break;
case SNK_NEGOTIATE_CAPABILITIES: