usb: typec: tcpm: Add Callback to Usb Communication capable partner

The USB Communications Capable bit indicates if port
partner is capable of communication over the USB data lines
(e.g. D+/- or SS Tx/Rx). Notify the status of the bit to low
level drivers to perform chip specific operation.
For instance, low level driver enables USB switches on D+/D-
lines to set up data path when the bit is set.

Refactored from patch initially authored by
Kyle Tso <kyletso@google.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20210202003101.221145-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 7747c7a..8558ab0 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -3430,6 +3430,14 @@ static void tcpm_unregister_altmodes(struct tcpm_port *port)
        memset(modep, 0, sizeof(*modep));
 }
 
+static void tcpm_set_partner_usb_comm_capable(struct tcpm_port *port, bool capable)
+{
+       tcpm_log(port, "Setting usb_comm capable %s", capable ? "true" : "false");
+
+       if (port->tcpc->set_partner_usb_comm_capable)
+               port->tcpc->set_partner_usb_comm_capable(port->tcpc, capable);
+}
+
 static void tcpm_reset_port(struct tcpm_port *port)
 {
        int ret;
@@ -3446,6 +3454,7 @@ static void tcpm_reset_port(struct tcpm_port *port)
        port->attached = false;
        port->pd_capable = false;
        port->pps_data.supported = false;
+       tcpm_set_partner_usb_comm_capable(port, false);
 
        /*
         * First Rx ID should be 0; set this to a sentinel of -1 so that
@@ -3786,6 +3795,8 @@ static void run_state_machine(struct tcpm_port *port)
                        }
                } else {
                        tcpm_pd_send_control(port, PD_CTRL_ACCEPT);
+                       tcpm_set_partner_usb_comm_capable(port,
+                                                         !!(port->sink_request & RDO_USB_COMM));
                        tcpm_set_state(port, SRC_TRANSITION_SUPPLY,
                                       PD_T_SRC_TRANSITION);
                }
@@ -4005,6 +4016,8 @@ static void run_state_machine(struct tcpm_port *port)
                break;
        case SNK_NEGOTIATE_CAPABILITIES:
                port->pd_capable = true;
+               tcpm_set_partner_usb_comm_capable(port,
+                                                 !!(port->source_caps[0] & PDO_FIXED_USB_COMM));
                port->hard_reset_count = 0;
                ret = tcpm_pd_send_request(port);
                if (ret < 0) {

diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index 3af99f8..42fcfbe 100644 (file)
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -108,6 +108,10 @@ enum tcpm_transmit_type {
  *             is supported by TCPC, set this callback for TCPM to query
  *             whether vbus is at VSAFE0V when needed.
  *             Returns true when vbus is at VSAFE0V, false otherwise.
+ * @set_partner_usb_comm_capable:
+ *              Optional; The USB Communications Capable bit indicates if port
+ *              partner is capable of communication over the USB data lines
+ *              (e.g. D+/- or SS Tx/Rx). Called to notify the status of the bit.
  */
 struct tcpc_dev {
        struct fwnode_handle *fwnode;
@@ -139,6 +143,7 @@ struct tcpc_dev {
        int (*set_auto_vbus_discharge_threshold)(struct tcpc_dev *dev, enum typec_pwr_opmode mode,
                                                 bool pps_active, u32 requested_vbus_voltage);
        bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev);
+       void (*set_partner_usb_comm_capable)(struct tcpc_dev *dev, bool enable);
 };
 
 struct tcpm_port;