During hard reset, TCPM turns off the charging path.
The spec provides an option for Sink to either drop to vSafe5V or vSafe0V.
>From USB_PD_R3_0
2.6.2 Sink Operation
..
Serious errors are handled by Hard Reset Signaling issued by either Port
Partner. A Hard Reset:
resets protocol as for a Soft Reset but also returns the power supply to
USB Default Operation (vSafe0V or vSafe5V output) in order to protect the
Sink.
Add a config option to tcpc_dev and let the device specific driver decide
what needs to be done.
Signed-off-by: Badhri Jagan Sridharan <Badhri@xxxxxxxxxx>
---
drivers/usb/typec/tcpm.c | 7 ++++++-
include/linux/usb/tcpm.h | 1 +
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
index a4e0c027a2a9..350d1a7c4543 100644
--- a/drivers/usb/typec/tcpm.c
+++ b/drivers/usb/typec/tcpm.c
@@ -3269,7 +3269,12 @@ static void run_state_machine(struct tcpm_port *port)
case SNK_HARD_RESET_SINK_OFF:
memset(&port->pps_data, 0, sizeof(port->pps_data));
tcpm_set_vconn(port, false);
- tcpm_set_charge(port, false);
+ if (port->tcpc->config->vsafe_5v_hard_reset)
+ tcpm_set_current_limit(port,
+ tcpm_get_current_limit(port),
+ 5000);
+ else
+ tcpm_set_charge(port, false);
if (port->tcpc->config->self_powered)
tcpm_set_roles(port, true, TYPEC_SINK, TYPEC_DEVICE);
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index 50c74a77db55..c6e3ccecba70 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -90,6 +90,7 @@ struct tcpc_config {
enum typec_role default_role;
bool try_role_hw; /* try.{src,snk} implemented in hardware */
bool self_powered; /* port belongs to a self powered device */
+ bool vsafe_5v_hard_reset; /* Maintain VSAFE5V during hard reset */
const struct typec_altmode_desc *alt_modes;
};
--
2.19.0.397.gdd90340f6a-goog
