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Diffstat (limited to 'drivers/usb/roles/class.c')
-rw-r--r--drivers/usb/roles/class.c410
1 files changed, 410 insertions, 0 deletions
diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
new file mode 100644
index 0000000000..ae41578bd0
--- /dev/null
+++ b/drivers/usb/roles/class.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Role Switch Support
+ *
+ * Copyright (C) 2018 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ * Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/usb/role.h>
+#include <linux/property.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+
+static const struct class role_class = {
+ .name = "usb_role",
+};
+
+struct usb_role_switch {
+ struct device dev;
+ struct mutex lock; /* device lock*/
+ enum usb_role role;
+
+ /* From descriptor */
+ struct device *usb2_port;
+ struct device *usb3_port;
+ struct device *udc;
+ usb_role_switch_set_t set;
+ usb_role_switch_get_t get;
+ bool allow_userspace_control;
+};
+
+#define to_role_switch(d) container_of(d, struct usb_role_switch, dev)
+
+/**
+ * usb_role_switch_set_role - Set USB role for a switch
+ * @sw: USB role switch
+ * @role: USB role to be switched to
+ *
+ * Set USB role @role for @sw.
+ */
+int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(sw))
+ return 0;
+
+ mutex_lock(&sw->lock);
+
+ ret = sw->set(sw, role);
+ if (!ret) {
+ sw->role = role;
+ kobject_uevent(&sw->dev.kobj, KOBJ_CHANGE);
+ }
+
+ mutex_unlock(&sw->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_set_role);
+
+/**
+ * usb_role_switch_get_role - Get the USB role for a switch
+ * @sw: USB role switch
+ *
+ * Depending on the role-switch-driver this function returns either a cached
+ * value of the last set role, or reads back the actual value from the hardware.
+ */
+enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
+{
+ enum usb_role role;
+
+ if (IS_ERR_OR_NULL(sw))
+ return USB_ROLE_NONE;
+
+ mutex_lock(&sw->lock);
+
+ if (sw->get)
+ role = sw->get(sw);
+ else
+ role = sw->role;
+
+ mutex_unlock(&sw->lock);
+
+ return role;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get_role);
+
+static void *usb_role_switch_match(const struct fwnode_handle *fwnode, const char *id,
+ void *data)
+{
+ struct device *dev;
+
+ if (id && !fwnode_property_present(fwnode, id))
+ return NULL;
+
+ dev = class_find_device_by_fwnode(&role_class, fwnode);
+
+ return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
+static struct usb_role_switch *
+usb_role_switch_is_parent(struct fwnode_handle *fwnode)
+{
+ struct fwnode_handle *parent = fwnode_get_parent(fwnode);
+ struct device *dev;
+
+ if (!fwnode_property_present(parent, "usb-role-switch")) {
+ fwnode_handle_put(parent);
+ return NULL;
+ }
+
+ dev = class_find_device_by_fwnode(&role_class, parent);
+ fwnode_handle_put(parent);
+ return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
+/**
+ * usb_role_switch_get - Find USB role switch linked with the caller
+ * @dev: The caller device
+ *
+ * Finds and returns role switch linked with @dev. The reference count for the
+ * found switch is incremented.
+ */
+struct usb_role_switch *usb_role_switch_get(struct device *dev)
+{
+ struct usb_role_switch *sw;
+
+ sw = usb_role_switch_is_parent(dev_fwnode(dev));
+ if (!sw)
+ sw = device_connection_find_match(dev, "usb-role-switch", NULL,
+ usb_role_switch_match);
+
+ if (!IS_ERR_OR_NULL(sw))
+ WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+
+ return sw;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get);
+
+/**
+ * fwnode_usb_role_switch_get - Find USB role switch linked with the caller
+ * @fwnode: The caller device node
+ *
+ * This is similar to the usb_role_switch_get() function above, but it searches
+ * the switch using fwnode instead of device entry.
+ */
+struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
+{
+ struct usb_role_switch *sw;
+
+ sw = usb_role_switch_is_parent(fwnode);
+ if (!sw)
+ sw = fwnode_connection_find_match(fwnode, "usb-role-switch",
+ NULL, usb_role_switch_match);
+ if (!IS_ERR_OR_NULL(sw))
+ WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
+
+ return sw;
+}
+EXPORT_SYMBOL_GPL(fwnode_usb_role_switch_get);
+
+/**
+ * usb_role_switch_put - Release handle to a switch
+ * @sw: USB Role Switch
+ *
+ * Decrement reference count for @sw.
+ */
+void usb_role_switch_put(struct usb_role_switch *sw)
+{
+ if (!IS_ERR_OR_NULL(sw)) {
+ module_put(sw->dev.parent->driver->owner);
+ put_device(&sw->dev);
+ }
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_put);
+
+/**
+ * usb_role_switch_find_by_fwnode - Find USB role switch with its fwnode
+ * @fwnode: fwnode of the USB Role Switch
+ *
+ * Finds and returns role switch with @fwnode. The reference count for the
+ * found switch is incremented.
+ */
+struct usb_role_switch *
+usb_role_switch_find_by_fwnode(const struct fwnode_handle *fwnode)
+{
+ struct device *dev;
+
+ if (!fwnode)
+ return NULL;
+
+ dev = class_find_device_by_fwnode(&role_class, fwnode);
+ if (dev)
+ WARN_ON(!try_module_get(dev->parent->driver->owner));
+
+ return dev ? to_role_switch(dev) : NULL;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_find_by_fwnode);
+
+static umode_t
+usb_role_switch_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct usb_role_switch *sw = to_role_switch(dev);
+
+ if (sw->allow_userspace_control)
+ return attr->mode;
+
+ return 0;
+}
+
+static const char * const usb_roles[] = {
+ [USB_ROLE_NONE] = "none",
+ [USB_ROLE_HOST] = "host",
+ [USB_ROLE_DEVICE] = "device",
+};
+
+const char *usb_role_string(enum usb_role role)
+{
+ if (role < 0 || role >= ARRAY_SIZE(usb_roles))
+ return "unknown";
+
+ return usb_roles[role];
+}
+EXPORT_SYMBOL_GPL(usb_role_string);
+
+static ssize_t
+role_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct usb_role_switch *sw = to_role_switch(dev);
+ enum usb_role role = usb_role_switch_get_role(sw);
+
+ return sprintf(buf, "%s\n", usb_roles[role]);
+}
+
+static ssize_t role_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct usb_role_switch *sw = to_role_switch(dev);
+ int ret;
+
+ ret = sysfs_match_string(usb_roles, buf);
+ if (ret < 0) {
+ bool res;
+
+ /* Extra check if the user wants to disable the switch */
+ ret = kstrtobool(buf, &res);
+ if (ret || res)
+ return -EINVAL;
+ }
+
+ ret = usb_role_switch_set_role(sw, ret);
+ if (ret)
+ return ret;
+
+ return size;
+}
+static DEVICE_ATTR_RW(role);
+
+static struct attribute *usb_role_switch_attrs[] = {
+ &dev_attr_role.attr,
+ NULL,
+};
+
+static const struct attribute_group usb_role_switch_group = {
+ .is_visible = usb_role_switch_is_visible,
+ .attrs = usb_role_switch_attrs,
+};
+
+static const struct attribute_group *usb_role_switch_groups[] = {
+ &usb_role_switch_group,
+ NULL,
+};
+
+static int usb_role_switch_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+ int ret;
+
+ ret = add_uevent_var(env, "USB_ROLE_SWITCH=%s", dev_name(dev));
+ if (ret)
+ dev_err(dev, "failed to add uevent USB_ROLE_SWITCH\n");
+
+ return ret;
+}
+
+static void usb_role_switch_release(struct device *dev)
+{
+ struct usb_role_switch *sw = to_role_switch(dev);
+
+ kfree(sw);
+}
+
+static const struct device_type usb_role_dev_type = {
+ .name = "usb_role_switch",
+ .groups = usb_role_switch_groups,
+ .uevent = usb_role_switch_uevent,
+ .release = usb_role_switch_release,
+};
+
+/**
+ * usb_role_switch_register - Register USB Role Switch
+ * @parent: Parent device for the switch
+ * @desc: Description of the switch
+ *
+ * USB Role Switch is a device capable or choosing the role for USB connector.
+ * On platforms where the USB controller is dual-role capable, the controller
+ * driver will need to register the switch. On platforms where the USB host and
+ * USB device controllers behind the connector are separate, there will be a
+ * mux, and the driver for that mux will need to register the switch.
+ *
+ * Returns handle to a new role switch or ERR_PTR. The content of @desc is
+ * copied.
+ */
+struct usb_role_switch *
+usb_role_switch_register(struct device *parent,
+ const struct usb_role_switch_desc *desc)
+{
+ struct usb_role_switch *sw;
+ int ret;
+
+ if (!desc || !desc->set)
+ return ERR_PTR(-EINVAL);
+
+ sw = kzalloc(sizeof(*sw), GFP_KERNEL);
+ if (!sw)
+ return ERR_PTR(-ENOMEM);
+
+ mutex_init(&sw->lock);
+
+ sw->allow_userspace_control = desc->allow_userspace_control;
+ sw->usb2_port = desc->usb2_port;
+ sw->usb3_port = desc->usb3_port;
+ sw->udc = desc->udc;
+ sw->set = desc->set;
+ sw->get = desc->get;
+
+ sw->dev.parent = parent;
+ sw->dev.fwnode = desc->fwnode;
+ sw->dev.class = &role_class;
+ sw->dev.type = &usb_role_dev_type;
+ dev_set_drvdata(&sw->dev, desc->driver_data);
+ dev_set_name(&sw->dev, "%s-role-switch",
+ desc->name ? desc->name : dev_name(parent));
+
+ ret = device_register(&sw->dev);
+ if (ret) {
+ put_device(&sw->dev);
+ return ERR_PTR(ret);
+ }
+
+ /* TODO: Symlinks for the host port and the device controller. */
+
+ return sw;
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_register);
+
+/**
+ * usb_role_switch_unregister - Unregsiter USB Role Switch
+ * @sw: USB Role Switch
+ *
+ * Unregister switch that was registered with usb_role_switch_register().
+ */
+void usb_role_switch_unregister(struct usb_role_switch *sw)
+{
+ if (!IS_ERR_OR_NULL(sw))
+ device_unregister(&sw->dev);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_unregister);
+
+/**
+ * usb_role_switch_set_drvdata - Assign private data pointer to a switch
+ * @sw: USB Role Switch
+ * @data: Private data pointer
+ */
+void usb_role_switch_set_drvdata(struct usb_role_switch *sw, void *data)
+{
+ dev_set_drvdata(&sw->dev, data);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_set_drvdata);
+
+/**
+ * usb_role_switch_get_drvdata - Get the private data pointer of a switch
+ * @sw: USB Role Switch
+ */
+void *usb_role_switch_get_drvdata(struct usb_role_switch *sw)
+{
+ return dev_get_drvdata(&sw->dev);
+}
+EXPORT_SYMBOL_GPL(usb_role_switch_get_drvdata);
+
+static int __init usb_roles_init(void)
+{
+ return class_register(&role_class);
+}
+subsys_initcall(usb_roles_init);
+
+static void __exit usb_roles_exit(void)
+{
+ class_unregister(&role_class);
+}
+module_exit(usb_roles_exit);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("USB Role Class");