usb: typec: maxim_contaminant: re-enable cc toggle if cc is open and port is clean

Presently in `max_contaminant_is_contaminant()` if there's no
contaminant detected previously, CC is open & stopped toggling and no
contaminant is currently present, TCPC.RC would be programmed to do DRP
toggling. However, it didn't actively look for a connection. This would
lead to Type-C not detect *any* new connections. Hence, in the above
situation, re-enable toggling & program TCPC to look for a new
connection.

Also, return early if TCPC was looking for connection as this indicates
TCPC has neither detected a potential connection nor a change in
contaminant state.

In addition, once dry detection is complete (port is dry), restart
toggling.

Fixes: 02b332a06397e ("usb: typec: maxim_contaminant: Implement check_contaminant callback")
Cc: stable <stable@kernel.org>
Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20250815-fix-upstream-contaminant-v2-2-6c8d6c3adafb@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/maxim_contaminant.c b/drivers/usb/typec/tcpm/maxim_contaminant.c
index 818cfe226ac7716de2fcbce205c67ea16acba592..af8da6dc60ae0bc5900f6614514d51f41eded8ab 100644 (file)
--- a/drivers/usb/typec/tcpm/maxim_contaminant.c
+++ b/drivers/usb/typec/tcpm/maxim_contaminant.c
@@ -329,6 +329,39 @@ static int max_contaminant_enable_dry_detection(struct max_tcpci_chip *chip)
        return 0;
 }
 
+static int max_contaminant_enable_toggling(struct max_tcpci_chip *chip)
+{
+       struct regmap *regmap = chip->data.regmap;
+       int ret;
+
+       /* Disable dry detection if enabled. */
+       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL2, CCLPMODESEL,
+                                FIELD_PREP(CCLPMODESEL,
+                                           LOW_POWER_MODE_DISABLE));
+       if (ret)
+               return ret;
+
+       ret = regmap_update_bits(regmap, TCPC_VENDOR_CC_CTRL1, CCCONNDRY, 0);
+       if (ret)
+               return ret;
+
+       ret = max_tcpci_write8(chip, TCPC_ROLE_CTRL, TCPC_ROLE_CTRL_DRP |
+                              FIELD_PREP(TCPC_ROLE_CTRL_CC1,
+                                         TCPC_ROLE_CTRL_CC_RD) |
+                              FIELD_PREP(TCPC_ROLE_CTRL_CC2,
+                                         TCPC_ROLE_CTRL_CC_RD));
+       if (ret)
+               return ret;
+
+       ret = regmap_update_bits(regmap, TCPC_TCPC_CTRL,
+                                TCPC_TCPC_CTRL_EN_LK4CONN_ALRT,
+                                TCPC_TCPC_CTRL_EN_LK4CONN_ALRT);
+       if (ret)
+               return ret;
+
+       return max_tcpci_write8(chip, TCPC_COMMAND, TCPC_CMD_LOOK4CONNECTION);
+}
+
 bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect_while_debounce,
                                    bool *cc_handled)
 {
@@ -345,6 +378,12 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
        if (ret < 0)
                return false;
 
+       if (cc_status & TCPC_CC_STATUS_TOGGLING) {
+               if (chip->contaminant_state == DETECTED)
+                       return true;
+               return false;
+       }
+
        if (chip->contaminant_state == NOT_DETECTED || chip->contaminant_state == SINK) {
                if (!disconnect_while_debounce)
                        msleep(100);
@@ -377,6 +416,12 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
                                max_contaminant_enable_dry_detection(chip);
                                return true;
                        }
+
+                       ret = max_contaminant_enable_toggling(chip);
+                       if (ret)
+                               dev_err(chip->dev,
+                                       "Failed to enable toggling, ret=%d",
+                                       ret);
                }
        } else if (chip->contaminant_state == DETECTED) {
                if (!(cc_status & TCPC_CC_STATUS_TOGGLING)) {
@@ -384,6 +429,14 @@ bool max_contaminant_is_contaminant(struct max_tcpci_chip *chip, bool disconnect
                        if (chip->contaminant_state == DETECTED) {
                                max_contaminant_enable_dry_detection(chip);
                                return true;
+                       } else {
+                               ret = max_contaminant_enable_toggling(chip);
+                               if (ret) {
+                                       dev_err(chip->dev,
+                                               "Failed to enable toggling, ret=%d",
+                                               ret);
+                                       return true;
+                               }
                        }
                }
        }