// SPDX-License-Identifier: GPL-2.0 /* * USB Role Switch Support * * Copyright (C) 2018 Intel Corporation * Author: Heikki Krogerus * Hans de Goede */ #include #include #include #include #include #include static struct class *role_class; 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->dev.parent, role); if (!ret) sw->role = role; 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->dev.parent); else role = sw->role; mutex_unlock(&sw->lock); return role; } EXPORT_SYMBOL_GPL(usb_role_switch_get_role); static void *usb_role_switch_match(struct device_connection *con, int ep, void *data) { struct device *dev; if (con->fwnode) { if (con->id && !fwnode_property_present(con->fwnode, con->id)) return NULL; dev = class_find_device_by_fwnode(role_class, con->fwnode); } else { dev = class_find_device_by_name(role_class, con->endpoint[ep]); } 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 (!parent || !fwnode_property_present(parent, "usb-role-switch")) return NULL; dev = class_find_device_by_fwnode(role_class, 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)) { put_device(&sw->dev); module_put(sw->dev.parent->driver->owner); } } EXPORT_SYMBOL_GPL(usb_role_switch_put); static umode_t usb_role_switch_is_visible(struct kobject *kobj, struct attribute *attr, int n) { struct device *dev = container_of(kobj, typeof(*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", }; 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(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_name(&sw->dev, "%s-role-switch", 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); static int __init usb_roles_init(void) { role_class = class_create(THIS_MODULE, "usb_role"); return PTR_ERR_OR_ZERO(role_class); } subsys_initcall(usb_roles_init); static void __exit usb_roles_exit(void) { class_destroy(role_class); } module_exit(usb_roles_exit); MODULE_AUTHOR("Heikki Krogerus "); MODULE_AUTHOR("Hans de Goede "); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("USB Role Class");