Message-Id: <20250821-atcphy-6-17-v1-19-172beda182b8@kernel.org>
Date: Thu, 21 Aug 2025 15:39:11 +0000
From: Sven Peter <sven@...nel.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Felipe Balbi <balbi@...nel.org>, 
 Janne Grunau <j@...nau.net>, Alyssa Rosenzweig <alyssa@...enzweig.io>, 
 Neal Gompa <neal@...pa.dev>, Vinod Koul <vkoul@...nel.org>, 
 Kishon Vijay Abraham I <kishon@...nel.org>, 
 Thinh Nguyen <Thinh.Nguyen@...opsys.com>, 
 Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
 Philipp Zabel <p.zabel@...gutronix.de>
Cc: linux-usb@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, asahi@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-phy@...ts.infradead.org, 
 Sven Peter <sven@...nel.org>, Hector Martin <marcan@...can.st>
Subject: [PATCH RFC 19/22] usb: typec: tipd: Handle mode transitions for
 CD321x

From: Hector Martin <marcan@...can.st>

On Apple Silicon machines there is no control over which alt mode is
chosen. The CD321x' firmware negotiates the target mode on its own and
only lets the main CPU know after the mode has already been chosen.
Especially after plugging a new cable in this can result to quick mode
changes from e.g. power only -> USB3 only -> USB3+DisplayPort in a short
time. It is not possile to influence this in any way and we also do not
get direct access to the PDOs or VDOs exchanged via USB PD.

Additionally, mode changes must be tightly synchronized between DWC3 and
the Type C PHY and most mode changes require a full reset of DWC3 to
make the port work correctly.
On the machines the usb role change is used to reset the controller.
The role change is additionally done synchronously from the callback
instead of relying on a workqueue as usual in order to avoid any races
which can, in the worst case, result in resetting the entire SoC if
Type-C PHY and DWC3 are out of sync.

To be able to control all this we trigger the entire process in the
correct order directly from the TIPD driver and de-bounce any mode
changes to avoid tearing down and re-setting DWC3 back up multiple times
any time a new connection is made.

Signed-off-by: Hector Martin <marcan@...can.st>
Co-developed-by: Sven Peter <sven@...nel.org>
Signed-off-by: Sven Peter <sven@...nel.org>
---
 drivers/usb/typec/tipd/core.c | 299 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 295 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
index bada42fbe59b29a9e864e17644da41908a445102..cad6adba131b8289645b1cabadc8d4216f0f0eee 100644
--- a/drivers/usb/typec/tipd/core.c
+++ b/drivers/usb/typec/tipd/core.c
@@ -17,6 +17,7 @@
 #include <linux/usb/typec.h>
 #include <linux/usb/typec_altmode.h>
 #include <linux/usb/typec_dp.h>
+#include <linux/usb/typec_mux.h>
 #include <linux/usb/typec_tbt.h>
 #include <linux/usb/role.h>
 #include <linux/workqueue.h>
@@ -121,6 +122,9 @@ struct tps6598x_intel_vid_status_reg {
 #define TPS_TASK_TIMEOUT		1
 #define TPS_TASK_REJECTED		3
 
+/* Debounce delay for mode changes, in milliseconds */
+#define CD321X_DEBOUNCE_DELAY_MS 500
+
 enum {
 	TPS_MODE_APP,
 	TPS_MODE_BOOT,
@@ -146,6 +150,7 @@ struct tipd_data {
 	irq_handler_t irq_handler;
 	u64 irq_mask1;
 	size_t tps_struct_size;
+	void (*remove)(struct tps6598x *tps);
 	int (*register_port)(struct tps6598x *tps, struct fwnode_handle *node);
 	void (*unregister_port)(struct tps6598x *tps);
 	void (*trace_data_status)(u32 status);
@@ -156,6 +161,7 @@ struct tipd_data {
 	int (*switch_power_state)(struct tps6598x *tps, u8 target_state);
 	bool (*read_data_status)(struct tps6598x *tps);
 	int (*reset)(struct tps6598x *tps);
+	int (*connect)(struct tps6598x *tps, u32 status);
 };
 
 struct tps6598x {
@@ -184,6 +190,17 @@ struct tps6598x {
 	const struct tipd_data *data;
 };
 
+struct cd321x_status {
+	u32 status;
+	u32 pwr_status;
+	u32 data_status;
+	u32 status_changed;
+	struct usb_pd_identity partner_identity;
+	struct tps6598x_dp_sid_status_reg dp_sid_status;
+	struct tps6598x_intel_vid_status_reg intel_vid_status;
+	struct tps6598x_usb4_status_reg usb4_status;
+};
+
 struct cd321x {
 	struct tps6598x tps;
 
@@ -193,6 +210,13 @@ struct cd321x {
 
 	struct typec_altmode *port_altmode_dp;
 	struct typec_altmode *port_altmode_tbt;
+
+	struct typec_mux *mux;
+	struct typec_mux_state state;
+
+	struct cd321x_status update_status;
+	struct delayed_work update_work;
+	struct usb_pd_identity cur_partner_identity;
 };
 
 static enum power_supply_property tps6598x_psy_props[] = {
@@ -614,9 +638,238 @@ static void tps6598x_handle_plug_event(struct tps6598x *tps, u32 status)
 	}
 }
 
+static void cd321x_typec_update_mode(struct tps6598x *tps, struct cd321x_status *st)
+{
+	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
+
+	if (st->data_status & TPS_DATA_STATUS_USB_DATA_ROLE)
+		cd321x->state.data_role = TYPEC_DEVICE;
+	else
+		cd321x->state.data_role = TYPEC_HOST;
+
+	if (!(st->data_status & TPS_DATA_STATUS_DATA_CONNECTION)) {
+		if (cd321x->state.mode == TYPEC_STATE_SAFE)
+			return;
+		cd321x->state.alt = NULL;
+		cd321x->state.mode = TYPEC_STATE_SAFE;
+		cd321x->state.data = NULL;
+		typec_mux_set(cd321x->mux, &cd321x->state);
+	} else if (st->data_status & TPS_DATA_STATUS_DP_CONNECTION) {
+		struct typec_displayport_data dp_data;
+		unsigned long mode;
+
+		switch (TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT(st->data_status)) {
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_A:
+			mode = TYPEC_DP_STATE_A;
+			break;
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_B:
+			mode = TYPEC_DP_STATE_B;
+			break;
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_C:
+			mode = TYPEC_DP_STATE_C;
+			break;
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_D:
+			mode = TYPEC_DP_STATE_D;
+			break;
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_E:
+			mode = TYPEC_DP_STATE_E;
+			break;
+		case TPS_DATA_STATUS_DP_SPEC_PIN_ASSIGNMENT_F:
+			mode = TYPEC_DP_STATE_F;
+			break;
+		default:
+			dev_err(tps->dev, "Invalid DP pin assignment\n");
+			return;
+		}
+
+		if (cd321x->state.alt == cd321x->port_altmode_dp &&
+		   cd321x->state.mode == mode) {
+			return;
+		}
+
+		dp_data.status = le32_to_cpu(st->dp_sid_status.status_rx);
+		dp_data.conf = le32_to_cpu(st->dp_sid_status.configure);
+		cd321x->state.alt = cd321x->port_altmode_dp;
+		cd321x->state.data = &dp_data;
+		cd321x->state.mode = mode;
+		typec_mux_set(cd321x->mux, &cd321x->state);
+	} else if (st->data_status & TPS_DATA_STATUS_TBT_CONNECTION) {
+		struct typec_thunderbolt_data tbt_data;
+
+		if (cd321x->state.alt == cd321x->port_altmode_tbt &&
+		   cd321x->state.mode == TYPEC_TBT_MODE)
+			return;
+
+		tbt_data.cable_mode = le16_to_cpu(st->intel_vid_status.cable_mode);
+		tbt_data.device_mode = le16_to_cpu(st->intel_vid_status.device_mode);
+		tbt_data.enter_vdo = le16_to_cpu(st->intel_vid_status.enter_vdo);
+		cd321x->state.alt = cd321x->port_altmode_tbt;
+		cd321x->state.mode = TYPEC_TBT_MODE;
+		cd321x->state.data = &tbt_data;
+		typec_mux_set(cd321x->mux, &cd321x->state);
+	} else if (st->data_status & CD321X_DATA_STATUS_USB4_CONNECTION) {
+		struct enter_usb_data eusb_data;
+
+		if (cd321x->state.alt == NULL && cd321x->state.mode == TYPEC_MODE_USB4)
+			return;
+
+		eusb_data.eudo = le32_to_cpu(st->usb4_status.eudo);
+		eusb_data.active_link_training =
+			!!(st->data_status & TPS_DATA_STATUS_ACTIVE_LINK_TRAIN);
+
+		cd321x->state.alt = NULL;
+		cd321x->state.data = &eusb_data;
+		cd321x->state.mode = TYPEC_MODE_USB4;
+		typec_mux_set(cd321x->mux, &cd321x->state);
+	} else {
+		if (cd321x->state.alt == NULL && cd321x->state.mode == TYPEC_STATE_USB)
+			return;
+		cd321x->state.alt = NULL;
+		cd321x->state.mode = TYPEC_STATE_USB;
+		cd321x->state.data = NULL;
+		typec_mux_set(cd321x->mux, &cd321x->state);
+	}
+}
+
+static void cd321x_update_work(struct work_struct *work)
+{
+	struct cd321x *cd321x = container_of(to_delayed_work(work),
+					    struct cd321x, update_work);
+	struct tps6598x *tps = &cd321x->tps;
+	struct cd321x_status st;
+	guard(mutex)(&tps->lock);
+
+	st = cd321x->update_status;
+	cd321x->update_status.status_changed = 0;
+
+	bool old_connected = !!tps->partner;
+	bool new_connected = st.status & TPS_STATUS_PLUG_PRESENT;
+	bool was_disconnected = st.status_changed & TPS_STATUS_PLUG_PRESENT;
+
+	bool usb_connection = st.data_status &
+			      (TPS_DATA_STATUS_USB2_CONNECTION | TPS_DATA_STATUS_USB3_CONNECTION);
+
+	enum usb_role old_role = usb_role_switch_get_role(tps->role_sw);
+	enum usb_role new_role = USB_ROLE_NONE;
+	enum typec_pwr_opmode pwr_opmode = TYPEC_PWR_MODE_USB;
+	enum typec_orientation orientation = TYPEC_ORIENTATION_NONE;
+
+	if (usb_connection) {
+		if (tps->data_status & TPS_DATA_STATUS_USB_DATA_ROLE)
+			new_role = USB_ROLE_DEVICE;
+		else
+			new_role = USB_ROLE_HOST;
+	}
+
+	if (new_connected) {
+		pwr_opmode = TPS_POWER_STATUS_PWROPMODE(st.pwr_status);
+		orientation = TPS_STATUS_TO_UPSIDE_DOWN(st.status) ?
+			TYPEC_ORIENTATION_REVERSE : TYPEC_ORIENTATION_NORMAL;
+	}
+
+	bool is_pd = pwr_opmode == TYPEC_PWR_MODE_PD;
+	bool partner_changed = old_connected && new_connected &&
+		(was_disconnected ||
+		 (is_pd && memcmp(&st.partner_identity,
+				  &cd321x->cur_partner_identity, sizeof(struct usb_pd_identity))));
+
+	/* If we are switching from an active role, transition to USB_ROLE_NONE first */
+	if (old_role != USB_ROLE_NONE && (new_role != old_role || was_disconnected))
+		usb_role_switch_set_role(tps->role_sw, USB_ROLE_NONE);
+
+	/* Process partner disconnection or change */
+	if (!new_connected || partner_changed) {
+		if (!IS_ERR(tps->partner))
+			typec_unregister_partner(tps->partner);
+		tps->partner = NULL;
+	}
+
+	/* If there was a disconnection, set PHY to off */
+	if (!new_connected || was_disconnected) {
+		cd321x->state.alt = NULL;
+		cd321x->state.mode = TYPEC_STATE_SAFE;
+		cd321x->state.data = NULL;
+		typec_set_mode(tps->port, TYPEC_STATE_SAFE);
+	}
+
+	/* Update Type-C properties */
+	typec_set_pwr_opmode(tps->port, pwr_opmode);
+	typec_set_pwr_role(tps->port, TPS_STATUS_TO_TYPEC_PORTROLE(st.status));
+	typec_set_vconn_role(tps->port, TPS_STATUS_TO_TYPEC_VCONN(st.status));
+	typec_set_orientation(tps->port, orientation);
+	typec_set_data_role(tps->port, TPS_STATUS_TO_TYPEC_DATAROLE(st.status));
+	power_supply_changed(tps->psy);
+
+	/* If the plug is disconnected, we are done */
+	if (!new_connected)
+		return;
+
+	/* Set up partner if we were previously disconnected (or changed). */
+	if (!tps->partner) {
+		struct typec_partner_desc desc;
+		desc.usb_pd = is_pd;
+		desc.accessory = TYPEC_ACCESSORY_NONE; /* XXX: handle accessories */
+		desc.identity = NULL;
+
+		if (desc.usb_pd)
+			desc.identity = &st.partner_identity;
+
+		tps->partner = typec_register_partner(tps->port, &desc);
+		if (IS_ERR(tps->partner))
+			dev_warn(tps->dev, "%s: failed to register partnet\n", __func__);
+
+		if (desc.identity) {
+			typec_partner_set_identity(tps->partner);
+			cd321x->cur_partner_identity = st.partner_identity;
+		}
+	}
+
+	/* Update the TypeC MUX/PHY state */
+	cd321x_typec_update_mode(tps, &st);
+
+	/* Launch the USB role switch */
+	usb_role_switch_set_role(tps->role_sw, new_role);
+
+	power_supply_changed(tps->psy);
+}
+
+static void cd321x_queue_status(struct tps6598x *tps)
+{
+	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
+
+	cd321x->update_status.status_changed |= cd321x->update_status.status ^ tps->status;
+
+	cd321x->update_status.status = tps->status;
+	cd321x->update_status.pwr_status = tps->pwr_status;
+	cd321x->update_status.data_status = tps->data_status;
+
+	cd321x->update_status.partner_identity = tps->partner_identity;
+	cd321x->update_status.dp_sid_status = cd321x->dp_sid_status;
+	cd321x->update_status.intel_vid_status = cd321x->intel_vid_status;
+	cd321x->update_status.usb4_status = cd321x->usb4_status;
+}
+
+static int cd321x_connect(struct tps6598x *tps, u32 status)
+{
+	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
+
+	/*
+	 * This is only called from _probe such that update_work can be
+	 * initialized and then scheduled for the first time to handle
+	 * plugs already connected at boot time.
+	 */
+	INIT_DELAYED_WORK(&cd321x->update_work, cd321x_update_work);
+	tps->status = status;
+	cd321x_queue_status(tps);
+	schedule_delayed_work(&cd321x->update_work, msecs_to_jiffies(CD321X_DEBOUNCE_DELAY_MS));
+
+	return 0;
+}
+
 static irqreturn_t cd321x_interrupt(int irq, void *data)
 {
 	struct tps6598x *tps = data;
+	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
 	u64 event = 0;
 	u32 status;
 	int ret;
@@ -653,9 +906,15 @@ static irqreturn_t cd321x_interrupt(int irq, void *data)
 		if (!tps->data->read_data_status(tps))
 			goto err_unlock;
 
-	/* Handle plug insert or removal */
-	if (event & APPLE_CD_REG_INT_PLUG_EVENT)
-		tps6598x_handle_plug_event(tps, status);
+	cd321x_queue_status(tps);
+	tps->status = status;
+
+	/*
+	 * Cancel pending work if not already running.
+	 * We will requeue the work after CD321X_DEBOUNCE_DELAY_MS regardless.
+	 */
+	cancel_delayed_work(&cd321x->update_work);
+	schedule_delayed_work(&cd321x->update_work, msecs_to_jiffies(CD321X_DEBOUNCE_DELAY_MS));
 
 err_unlock:
 	mutex_unlock(&tps->lock);
@@ -1023,10 +1282,26 @@ cd321x_register_port(struct tps6598x *tps, struct fwnode_handle *fwnode)
 	if (ret)
 		goto err_unregister_port;
 
+	cd321x->mux = fwnode_typec_mux_get(fwnode);
+	if (IS_ERR(cd321x->mux)) {
+		ret = PTR_ERR(cd321x->mux);
+		goto err_unregister_altmodes;
+	}
+
+	cd321x->state.alt = NULL;
+	cd321x->state.mode = TYPEC_STATE_SAFE;
+	cd321x->state.data = NULL;
 	typec_set_mode(tps->port, TYPEC_STATE_SAFE);
 
 	return 0;
 
+err_unregister_altmodes:
+	if (cd321x->port_altmode_dp)
+		typec_unregister_altmode(cd321x->port_altmode_dp);
+	if (cd321x->port_altmode_tbt)
+		typec_unregister_altmode(cd321x->port_altmode_tbt);
+	cd321x->port_altmode_dp = NULL;
+	cd321x->port_altmode_tbt = NULL;
 err_unregister_port:
 	typec_unregister_port(tps->port);
 	return ret;
@@ -1043,6 +1318,8 @@ cd321x_unregister_port(struct tps6598x *tps)
 {
 	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
 
+	if (cd321x->mux)
+		typec_mux_put(cd321x->mux);
 	if (cd321x->port_altmode_dp)
 		typec_unregister_altmode(cd321x->port_altmode_dp);
 	if (cd321x->port_altmode_tbt)
@@ -1457,6 +1734,13 @@ tps25750_register_port(struct tps6598x *tps, struct fwnode_handle *fwnode)
 	return 0;
 }
 
+static void cd321x_remove(struct tps6598x *tps)
+{
+	struct cd321x *cd321x = container_of(tps, struct cd321x, tps);
+
+	cancel_delayed_work_sync(&cd321x->update_work);
+}
+
 static int tps6598x_probe(struct i2c_client *client)
 {
 	const struct tipd_data *data;
@@ -1558,7 +1842,7 @@ static int tps6598x_probe(struct i2c_client *client)
 			goto err_unregister_port;
 		if (!tps->data->read_data_status(tps))
 			goto err_unregister_port;
-		ret = tps6598x_connect(tps, status);
+		ret = tps->data->connect(tps, status);
 		if (ret)
 			dev_err(&client->dev, "failed to register partner\n");
 	}
@@ -1615,6 +1899,9 @@ static void tps6598x_remove(struct i2c_client *client)
 	else
 		devm_free_irq(tps->dev, client->irq, tps);
 
+	if (tps->data->remove)
+		tps->data->remove(tps);
+
 	tps6598x_disconnect(tps, 0);
 	tps->data->unregister_port(tps);
 	usb_role_switch_put(tps->role_sw);
@@ -1685,6 +1972,7 @@ static const struct tipd_data cd321x_data = {
 		     APPLE_CD_REG_INT_DATA_STATUS_UPDATE |
 		     APPLE_CD_REG_INT_PLUG_EVENT,
 	.tps_struct_size = sizeof(struct cd321x),
+	.remove = cd321x_remove,
 	.register_port = cd321x_register_port,
 	.unregister_port = cd321x_unregister_port,
 	.trace_data_status = trace_cd321x_data_status,
@@ -1694,6 +1982,7 @@ static const struct tipd_data cd321x_data = {
 	.read_data_status = cd321x_read_data_status,
 	.reset = cd321x_reset,
 	.switch_power_state = cd321x_switch_power_state,
+	.connect = cd321x_connect,
 };
 
 static const struct tipd_data tps6598x_data = {
@@ -1711,6 +2000,7 @@ static const struct tipd_data tps6598x_data = {
 	.init = tps6598x_init,
 	.read_data_status = tps6598x_read_data_status,
 	.reset = tps6598x_reset,
+	.connect = tps6598x_connect,
 };
 
 static const struct tipd_data tps25750_data = {
@@ -1728,6 +2018,7 @@ static const struct tipd_data tps25750_data = {
 	.init = tps25750_init,
 	.read_data_status = tps6598x_read_data_status,
 	.reset = tps25750_reset,
+	.connect = tps6598x_connect,
 };
 
 static const struct of_device_id tps6598x_of_match[] = {

-- 
2.34.1

Powered by blists - more mailing lists