[PATCH v8 10/16] usb: hub: Power on connected M.2 E-key connectors with power sequencing API

@@ -44,6 +44,7 @@ config USB_ARCH_HAS_HCD
 config USB
 	tristate "Support for Host-side USB"
 	depends on USB_ARCH_HAS_HCD
+	depends on POWER_SEQUENCING if POWER_SEQUENCING
 	select GENERIC_ALLOCATOR
 	select USB_COMMON
 	select NLS  # for UTF-8 strings

@@ -33,6 +33,7 @@
 #include <linux/mutex.h>
 #include <linux/random.h>
 #include <linux/pm_qos.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/kobject.h>
 
 #include <linux/bitfield.h>

@@ -875,6 +876,16 @@ static void hub_tt_work(struct work_struct *work)
 	spin_unlock_irqrestore(&hub->tt.lock, flags);
 }
 
+static int usb_hub_set_port_pwrseq(struct usb_port *port, bool on)
+{
+	if (!IS_ENABLED(CONFIG_POWER_SEQUENCING))
+		return 0;
+
+	if (on)
+		return pwrseq_enable(port->pwrseq);
+	return pwrseq_disable(port->pwrseq);
+}
+
 /**
  * usb_hub_set_port_power - control hub port's power state
  * @hdev: USB device belonging to the usb hub

@@ -890,15 +901,22 @@ static void hub_tt_work(struct work_struct *work)
 int usb_hub_set_port_power(struct usb_device *hdev, struct usb_hub *hub,
 			   int port1, bool set)
 {
+	struct usb_port *pwrseq_port = hub->ports[port1 - 1];
 	int ret;
 
+	ret = usb_hub_set_port_pwrseq(pwrseq_port, set);
+	if (ret)
+		return ret;
+
 	if (set)
 		ret = set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
 	else
 		ret = usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
 
-	if (ret)
+	if (ret) {
+		usb_hub_set_port_pwrseq(pwrseq_port, !set);
 		return ret;
+	}
 
 	assign_bit(port1, hub->power_bits, set);
 	return 0;

@@ -103,7 +103,15 @@ static inline bool hub_is_port_power_switchable(struct usb_hub *hub)
 	if (!hub)
 		return false;
 	hcs = hub->descriptor->wHubCharacteristics;
-	return (le16_to_cpu(hcs) & HUB_CHAR_LPSM) < HUB_CHAR_NO_LPSM;
+	if ((le16_to_cpu(hcs) & HUB_CHAR_LPSM) < HUB_CHAR_NO_LPSM)
+		return true;
+	/* check for controllable external power sequencers */
+	for (unsigned int i = 0; i < hub->hdev->maxchild; i++) {
+		if (hub->ports[i] && hub->ports[i]->pwrseq)
+			return true;
+	}
+
+	return false;
 }
 
 static inline int hub_is_superspeed(struct usb_device *hdev)

@@ -8,11 +8,14 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/cleanup.h>
 #include <linux/kstrtox.h>
 #include <linux/slab.h>
 #include <linux/string_choices.h>
 #include <linux/sysfs.h>
 #include <linux/pm_qos.h>
+#include <linux/property.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/component.h>
 #include <linux/usb/of.h>
 

@@ -26,6 +29,7 @@ static const struct attribute_group *port_dev_group[];
 int usb_port_is_power_on(struct usb_port *port, unsigned int portstatus)
 {
 	int ret = 0;
+	int pwrseq_state;
 
 	if (port->is_superspeed) {
 		if (portstatus & USB_SS_PORT_STAT_POWER)

@@ -35,7 +39,13 @@ int usb_port_is_power_on(struct usb_port *port, unsigned int portstatus)
 			ret = 1;
 	}
 
-	return ret;
+	/* stub function returns error */
+	pwrseq_state = pwrseq_get_state(port->pwrseq);
+	/* fall back to port status if pwrseq is in unknown state */
+	if (pwrseq_state < 0 || pwrseq_state == PWRSEQ_STATE_UNKNOWN)
+		return ret;
+
+	return ret && pwrseq_state == PWRSEQ_STATE_ON;
 }
 
 static bool usb_port_allow_power_off(struct usb_device *hdev,

@@ -45,6 +55,9 @@ static bool usb_port_allow_power_off(struct usb_device *hdev,
 	if (hub_is_port_power_switchable(hub))
 		return true;
 
+	if (port_dev->pwrseq)
+		return true;
+
 	if (!IS_ENABLED(CONFIG_ACPI))
 		return false;
 

@@ -380,6 +393,8 @@ static void usb_port_device_release(struct device *dev)
 	 * device_platform_notify_remove() in device_del().
 	 */
 	fwnode_handle_put(dev_fwnode(dev));
+	/* usb_hub_create_port_device() could leave an error value */
+	pwrseq_put(port_dev->pwrseq);
 	kfree(port_dev->req);
 	kfree(port_dev);
 }

@@ -772,11 +787,46 @@ static const struct component_ops connector_ops = {
 	.unbind = connector_unbind,
 };
 
+static bool port_pwrseq_is_supported(struct usb_port *port_dev)
+{
+	struct device *dev = &port_dev->dev;
+	struct fwnode_handle *port = dev_fwnode(dev);
+
+	struct fwnode_handle *ep __free(fwnode_handle) =
+			fwnode_graph_get_next_port_endpoint(port, NULL);
+	if (!ep)
+		return false;
+
+	struct fwnode_handle *remote __free(fwnode_handle) =
+			fwnode_graph_get_remote_port_parent(ep);
+	if (!remote)
+		return false;
+
+	if (!fwnode_device_is_compatible(remote, "pcie-m2-e-connector")) {
+		dev_dbg(dev, "remote endpoint %pfw is not a supported connector", remote);
+		return false;
+	}
+
+	return true;
+}
+
+static struct pwrseq_desc *usb_hub_port_pwrseq_get(struct usb_port *port_dev)
+{
+	if (!IS_ENABLED(CONFIG_POWER_SEQUENCING))
+		return NULL;
+
+	if (!port_pwrseq_is_supported(port_dev))
+		return NULL;
+
+	return pwrseq_get(&port_dev->dev, "usb");
+}
+
 int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 {
 	struct usb_port *port_dev;
 	struct usb_device *hdev = hub->hdev;
 	struct fwnode_handle *fwnode = dev_fwnode(&hdev->dev);
+	struct pwrseq_desc *pwrseq;
 	int retval;
 
 	port_dev = kzalloc_obj(*port_dev);

@@ -827,6 +877,7 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 	retval = device_register(&port_dev->dev);
 	if (retval) {
 		put_device(&port_dev->dev);
+		hub->ports[port1 - 1] = NULL;
 		return retval;
 	}
 

@@ -844,6 +895,14 @@ int usb_hub_create_port_device(struct usb_hub *hub, int port1)
 		goto err_put_kn;
 	}
 
+	pwrseq = usb_hub_port_pwrseq_get(port_dev);
+	if (IS_ERR(pwrseq)) {
+		retval = dev_err_probe(&port_dev->dev, PTR_ERR(pwrseq),
+				       "failed to get power sequencing descriptor\n");
+		goto err_put_kn;
+	}
+	port_dev->pwrseq = pwrseq;
+
 	retval = component_add(&port_dev->dev, &connector_ops);
 	if (retval) {
 		dev_warn(&port_dev->dev, "failed to add component\n");

@@ -901,6 +960,7 @@ void usb_hub_remove_port_device(struct usb_hub *hub, int port1)
 	peer = port_dev->peer;
 	if (peer)
 		unlink_peers(port_dev, peer);
+	pwrseq_disable(port_dev->pwrseq);
 	component_del(&port_dev->dev, &connector_ops);
 	sysfs_put(port_dev->state_kn);
 	device_unregister(&port_dev->dev);

@@ -25,6 +25,7 @@
  * @port_owner: port's owner
  * @peer: related usb2 and usb3 ports (share the same connector)
  * @connector: USB Type-C connector
+ * @pwrseq: power sequencing descriptor for the port
  * @req: default pm qos request for hubs without port power control
  * @connect_type: port's connect type
  * @state: device state of the usb device attached to the port

@@ -44,6 +45,7 @@ struct usb_port {
 	struct usb_dev_state *port_owner;
 	struct usb_port *peer;
 	struct typec_connector *connector;
+	struct pwrseq_desc *pwrseq;
 	struct dev_pm_qos_request *req;
 	enum usb_port_connect_type connect_type;
 	enum usb_device_state state;