On Fri, Jan 21, 2022 at 05:55:20PM -0800, Badhri Jagan Sridharan wrote:
> 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@xxxxxxxxxxxxxxx
> Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index b8afe3d8c882..5fce795b69c7 100644
> --- 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);
> --
> 2.35.0.rc0.227.g00780c9af4-goog
--
heikki
