usb: typec: tcpci: update ROLE_CONTROL for DRP

ROLE_CONTROL register would not have the actual CC terminations
unless the port does not set ROLE_CONTROL.DRP. For DRP ports,
CC_STATUS.cc1/cc2 indicates the final terminations applied
when TCPC enters potential_connect_as_source/_sink.
For DRP ports, infer port role from CC_STATUS and set corresponding
CC terminations before setting the orientation.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20200901025927.3596190-4-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index 7d36d5e..7d9491b 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -191,12 +191,47 @@ static int tcpci_set_polarity(struct tcpc_dev *tcpc,
        struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
        unsigned int reg;
        int ret;
+       enum typec_cc_status cc1, cc2;
 
-       /* Keep the disconnect cc line open */
+       /* Obtain Rp setting from role control */
        ret = regmap_read(tcpci->regmap, TCPC_ROLE_CTRL, &reg);
        if (ret < 0)
                return ret;
 
+       ret = tcpci_get_cc(tcpc, &cc1, &cc2);
+       if (ret < 0)
+               return ret;
+
+       /*
+        * When port has drp toggling enabled, ROLE_CONTROL would only have the initial
+        * terminations for the toggling and does not indicate the final cc
+        * terminations when ConnectionResult is 0 i.e. drp toggling stops and
+        * the connection is resolbed. Infer port role from TCPC_CC_STATUS based on the
+        * terminations seen. The port role is then used to set the cc terminations.
+        */
+       if (reg & TCPC_ROLE_CTRL_DRP) {
+               /* Disable DRP for the OPEN setting to take effect */
+               reg = reg & ~TCPC_ROLE_CTRL_DRP;
+
+               if (polarity == TYPEC_POLARITY_CC2) {
+                       reg &= ~(TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT);
+                       /* Local port is source */
+                       if (cc2 == TYPEC_CC_RD)
+                               /* Role control would have the Rp setting when DRP was enabled */
+                               reg |= TCPC_ROLE_CTRL_CC_RP << TCPC_ROLE_CTRL_CC2_SHIFT;
+                       else
+                               reg |= TCPC_ROLE_CTRL_CC_RD << TCPC_ROLE_CTRL_CC2_SHIFT;
+               } else {
+                       reg &= ~(TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT);
+                       /* Local port is source */
+                       if (cc1 == TYPEC_CC_RD)
+                               /* Role control would have the Rp setting when DRP was enabled */
+                               reg |= TCPC_ROLE_CTRL_CC_RP << TCPC_ROLE_CTRL_CC1_SHIFT;
+                       else
+                               reg |= TCPC_ROLE_CTRL_CC_RD << TCPC_ROLE_CTRL_CC1_SHIFT;
+               }
+       }
+
        if (polarity == TYPEC_POLARITY_CC2)
                reg |= TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC1_SHIFT;
        else