On Tue, Aug 11, 2020 at 01:02:28PM -0700, Badhri Jagan Sridharan wrote: > From the spec: > "7.1.5 Response to Hard Resets > Hard Reset Signaling indicates a communication failure has occurred and > the Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin > and Shall drive VBUS to vSafe0V as shown in Figure 7-9. The USB connection > May reset during a Hard Reset since the VBUS voltage will be less than > vSafe5V for an extended period of time. After establishing the vSafe0V > voltage condition on VBUS, the Source Shall wait tSrcRecover before > re-applying VCONN and restoring VBUS to vSafe5V. A Source Shall conform > to the VCONN timing as specified in [USB Type-C 1.3]." > > Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> Guenter > --- > Changes since V1 (Guenter's suggestion): > - Bound SRC_HARD_RESET_VBUS_ON to accommodate tcpc drivers which doesn't > update the vbus status. > --- > drivers/usb/typec/tcpm/tcpm.c | 28 +++++++++++++++++++++++++--- > 1 file changed, 25 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index 3ef37202ee37..a48e3f90d196 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -3372,13 +3372,31 @@ static void run_state_machine(struct tcpm_port *port) > tcpm_set_state(port, SNK_HARD_RESET_SINK_OFF, 0); > break; > case SRC_HARD_RESET_VBUS_OFF: > - tcpm_set_vconn(port, true); > + /* > + * 7.1.5 Response to Hard Resets > + * Hard Reset Signaling indicates a communication failure has occurred and the > + * Source Shall stop driving VCONN, Shall remove Rp from the VCONN pin and Shall > + * drive VBUS to vSafe0V as shown in Figure 7-9. > + */ > + tcpm_set_vconn(port, false); > tcpm_set_vbus(port, false); > tcpm_set_roles(port, port->self_powered, TYPEC_SOURCE, > tcpm_data_role_for_source(port)); > - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); > + /* > + * If tcpc fails to notify vbus off, TCPM will wait for PD_T_SAFE_0V + > + * PD_T_SRC_RECOVER before turning vbus back on. > + * From Table 7-12 Sequence Description for a Source Initiated Hard Reset: > + * 4. Policy Engine waits tPSHardReset after sending Hard Reset Signaling and then > + * tells the Device Policy Manager to instruct the power supply to perform a > + * Hard Reset. The transition to vSafe0V Shall occur within tSafe0V (t2). > + * 5. After tSrcRecover the Source applies power to VBUS in an attempt to > + * re-establish communication with the Sink and resume USB Default Operation. > + * The transition to vSafe5V Shall occur within tSrcTurnOn(t4). > + */ > + tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SAFE_0V + PD_T_SRC_RECOVER); > break; > case SRC_HARD_RESET_VBUS_ON: > + tcpm_set_vconn(port, true); > tcpm_set_vbus(port, true); > port->tcpc->set_pd_rx(port->tcpc, true); > tcpm_set_attached_state(port, true); > @@ -3944,7 +3962,11 @@ static void _tcpm_pd_vbus_off(struct tcpm_port *port) > tcpm_set_state(port, SNK_HARD_RESET_WAIT_VBUS, 0); > break; > case SRC_HARD_RESET_VBUS_OFF: > - tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, 0); > + /* > + * After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait > + * tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V. > + */ > + tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); > break; > case HARD_RESET_SEND: > break;
