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Date:   Sun,  4 Dec 2022 00:48:43 -0800
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Subject: [PATCH v3 2/3] usb: typec: tcpci: Add callback for evaluating
 contaminant presence
From:   Badhri Jagan Sridharan <badhri@google.com>
To:     Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Kyle Tso <kyletso@google.com>,
        Badhri Jagan Sridharan <badhri@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

This change adds callback to evaluate presence of contaminant in
the TCPCI layer.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
Changes since v2:
* Added tcpci_is_potential_contaminant to offload
* disconnect_while_debounce logic
---
 drivers/usb/typec/tcpm/tcpci.c | 20 ++++++++++++++++++++
 include/linux/usb/tcpci.h      | 13 +++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
index fe781a38dc82..2aadf785970f 100644
--- a/drivers/usb/typec/tcpm/tcpci.c
+++ b/drivers/usb/typec/tcpm/tcpci.c
@@ -403,6 +403,24 @@ static void tcpci_frs_sourcing_vbus(struct tcpc_dev *dev)
 		tcpci->data->frs_sourcing_vbus(tcpci, tcpci->data);
 }
 
+static bool tcpci_is_potential_contaminant(struct tcpc_dev *dev, enum tcpm_state current_state)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(dev);
+
+	if (tcpci->data->is_potential_contaminant)
+		return tcpci->data->is_potential_contaminant(tcpci, tcpci->data, current_state);
+
+	return false;
+}
+
+static void tcpci_check_contaminant(struct tcpc_dev *dev)
+{
+	struct tcpci *tcpci = tcpc_to_tcpci(dev);
+
+	if (tcpci->data->check_contaminant)
+		tcpci->data->check_contaminant(tcpci, tcpci->data);
+}
+
 static int tcpci_set_bist_data(struct tcpc_dev *tcpc, bool enable)
 {
 	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
@@ -777,6 +795,8 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
 	tcpci->tcpc.enable_frs = tcpci_enable_frs;
 	tcpci->tcpc.frs_sourcing_vbus = tcpci_frs_sourcing_vbus;
 	tcpci->tcpc.set_partner_usb_comm_capable = tcpci_set_partner_usb_comm_capable;
+	tcpci->tcpc.is_potential_contaminant = tcpci_is_potential_contaminant;
+	tcpci->tcpc.check_contaminant = tcpci_check_contaminant;
 
 	if (tcpci->data->auto_discharge_disconnect) {
 		tcpci->tcpc.enable_auto_vbus_discharge = tcpci_enable_auto_vbus_discharge;
diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
index 17657451c762..548e85fdc7fa 100644
--- a/include/linux/usb/tcpci.h
+++ b/include/linux/usb/tcpci.h
@@ -188,6 +188,16 @@ struct tcpci;
  *		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.
+ * @check_contaminant:
+ *		Optional; The callback is invoked when chiplevel drivers indicated
+ *		that the USB port needs to be checked for contaminant presence.
+ *		Chip level drivers are expected to check for contaminant and call
+ *		tcpm_clean_port when the port is clean to put the port back into
+ *		toggling state.
+ * @is_potential_contaminant:
+ *		Optional; TCPM invokes the callback for every TCPM state machine
+ *		transition. Chiplevel drivers can monitor the state machine
+ *		transitions to flag for potential contaminant presence.
  */
 struct tcpci_data {
 	struct regmap *regmap;
@@ -204,6 +214,9 @@ struct tcpci_data {
 	void (*frs_sourcing_vbus)(struct tcpci *tcpci, struct tcpci_data *data);
 	void (*set_partner_usb_comm_capable)(struct tcpci *tcpci, struct tcpci_data *data,
 					     bool capable);
+	void (*check_contaminant)(struct tcpci *tcpci, struct tcpci_data *data);
+	bool (*is_potential_contaminant)(struct tcpci *tcpci, struct tcpci_data *data,
+					 enum tcpm_state current_state);
 };
 
 struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data);
-- 
2.39.0.rc0.267.gcb52ba06e7-goog