usb: typec: tcpm: Do not disconnect when receiving VSAFE0V

commit 746f96e7d6f7a276726860f696671766bfb24cf0 upstream.

With some chargers, vbus might momentarily raise above VSAFE5V and fall
back to 0V causing VSAFE0V to be triggered. This will
will report a VBUS off event causing TCPM to transition to
SNK_UNATTACHED state where it should be waiting in either SNK_ATTACH_WAIT
or SNK_DEBOUNCED state. This patch makes TCPM avoid VSAFE0V 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: 28b43d3d746b8 ("usb: typec: tcpm: Introduce vsafe0v for vbus")
Cc: stable@vger.kernel.org
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20220122015520.332507-2-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index b8afe3d8c88264ebeb4f603e5985ea11b35daab1..5fce795b69c7f44b63a7f9401b5293c205cd2d4e 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -5264,6 +5264,10 @@ static void _tcpm_pd_vbus_vsafe0v(struct tcpm_port *port)
        case PR_SWAP_SNK_SRC_SOURCE_ON:
                /* Do nothing, vsafe0v is expected during transition */
                break;
+       case SNK_ATTACH_WAIT:
+       case SNK_DEBOUNCED:
+               /*Do nothing, still waiting for VSAFE5V for connect */
+               break;
        default:
                if (port->pwr_role == TYPEC_SINK && port->auto_vbus_discharge_enabled)
                        tcpm_set_state(port, SNK_UNATTACHED, 0);