On Mon, Oct 01, 2018 at 12:45:00PM -0700, Badhri Jagan Sridharan wrote: > During HARD_RESET the data link is disconnected. > For self powered device, the spec is advising against doing that. > > >From USB_PD_R3_0 > 7.1.5 Response to Hard Resets > Device operation during and after a Hard Reset is defined as follows: > Self-powered devices Should Not disconnect from USB during a Hard Reset > (see Section 9.1.2). > Bus powered devices will disconnect from USB during a Hard Reset due to the > loss of their power source. > > Tackle this by letting TCPM know whether the device is self or bus powered. > > This overcomes unnecessary port disconnections from hard reset. > Also, speeds up the enumeration time when connected to Type-A ports. > > Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > --------- > Version history: > V3: > Rebase on top of usb-next > > V2: > Based on feedback from heikki.krogerus@xxxxxxxxxxxxxxx > - self_powered added to the struct tcpm_port which is populated from > a. "connector" node of the device tree in tcpm_fw_get_caps() > b. "self_powered" node of the tcpc_config in tcpm_copy_caps > > Based on feedbase from linux@xxxxxxxxxxxx > - Code was refactored > - SRC_HARD_RESET_VBUS_OFF sets the link state to false based > on self_powered flag > > V1 located here: > https://lkml.org/lkml/2018/9/13/94 > --- > drivers/usb/typec/tcpm/tcpm.c | 12 ++++++++++-- > include/linux/usb/tcpm.h | 1 + > 2 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c > index 4f1f4215f3d6..c3ac0e46106b 100644 > --- a/drivers/usb/typec/tcpm/tcpm.c > +++ b/drivers/usb/typec/tcpm/tcpm.c > @@ -317,6 +317,9 @@ struct tcpm_port { > /* Deadline in jiffies to exit src_try_wait state */ > unsigned long max_wait; > > + /* port belongs to a self powered device */ > + bool self_powered; > + > #ifdef CONFIG_DEBUG_FS > struct dentry *dentry; > struct mutex logbuffer_lock; /* log buffer access lock */ > @@ -3257,7 +3260,8 @@ static void run_state_machine(struct tcpm_port *port) > case SRC_HARD_RESET_VBUS_OFF: > tcpm_set_vconn(port, true); > tcpm_set_vbus(port, false); > - tcpm_set_roles(port, false, TYPEC_SOURCE, TYPEC_HOST); > + tcpm_set_roles(port, port->self_powered, TYPEC_SOURCE, > + TYPEC_HOST); > tcpm_set_state(port, SRC_HARD_RESET_VBUS_ON, PD_T_SRC_RECOVER); > break; > case SRC_HARD_RESET_VBUS_ON: > @@ -3270,7 +3274,8 @@ static void run_state_machine(struct tcpm_port *port) > memset(&port->pps_data, 0, sizeof(port->pps_data)); > tcpm_set_vconn(port, false); > tcpm_set_charge(port, false); > - tcpm_set_roles(port, false, TYPEC_SINK, TYPEC_DEVICE); > + tcpm_set_roles(port, port->self_powered, TYPEC_SINK, > + TYPEC_DEVICE); > /* > * VBUS may or may not toggle, depending on the adapter. > * If it doesn't toggle, transition to SNK_HARD_RESET_SINK_ON > @@ -4409,6 +4414,8 @@ static int tcpm_fw_get_caps(struct tcpm_port *port, > return -EINVAL; > port->operating_snk_mw = mw / 1000; > > + port->self_powered = fwnode_property_read_bool(fwnode, "self-powered"); > + > return 0; > } > > @@ -4717,6 +4724,7 @@ static int tcpm_copy_caps(struct tcpm_port *port, > port->typec_caps.prefer_role = tcfg->default_role; > port->typec_caps.type = tcfg->type; > port->typec_caps.data = tcfg->data; > + port->self_powered = port->tcpc->config->self_powered; > > return 0; > } > diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h > index 7e7fbfb84e8e..50c74a77db55 100644 > --- a/include/linux/usb/tcpm.h > +++ b/include/linux/usb/tcpm.h > @@ -89,6 +89,7 @@ struct tcpc_config { > enum typec_port_data data; > 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 */ > > const struct typec_altmode_desc *alt_modes; > }; > -- > 2.19.0.605.g01d371f741-goog thanks, -- heikki
