On 8/10/20 6:11 PM, 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 <[email protected]> > --- > drivers/usb/typec/tcpm/tcpm.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index 3ef37202ee37..e41c4e5d3c71 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -3372,13 +3372,19 @@ 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);
I am a bit concerned about this. If I understand correctly, it means that we won't turn VBUS back on unless a SRC_HARD_RESET_VBUS_OFF PD event is received. Is that correct ? What happens if that event is never received ? Thanks, Guenter > 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 +3950,11 @@ 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; >
