1 // SPDX-License-Identifier: GPL-2.0
3  * USB Role Switch Support
10 #include <linux/usb/role.h>
21 	enum usb_role role;  member
35  * usb_role_switch_set_role - Set USB role for a switch
36  * @sw: USB role switch
37  * @role: USB role to be switched to
39  * Set USB role @role for @sw.
41 int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role)  in usb_role_switch_set_role()  argument
48 	mutex_lock(&sw->lock);  in usb_role_switch_set_role()
50 	ret = sw->set(sw->dev.parent, role);  in usb_role_switch_set_role()
52 		sw->role = role;  in usb_role_switch_set_role()
54 	mutex_unlock(&sw->lock);  in usb_role_switch_set_role()
61  * usb_role_switch_get_role - Get the USB role for a switch
62  * @sw: USB role switch
64  * Depending on the role-switch-driver this function returns either a cached
65  * value of the last set role, or reads back the actual value from the hardware.
69 	enum usb_role role;  in usb_role_switch_get_role()  local
74 	mutex_lock(&sw->lock);  in usb_role_switch_get_role()
76 	if (sw->get)  in usb_role_switch_get_role()
77 		role = sw->get(sw->dev.parent);  in usb_role_switch_get_role()
79 		role = sw->role;  in usb_role_switch_get_role()
81 	mutex_unlock(&sw->lock);  in usb_role_switch_get_role()
83 	return role;  in usb_role_switch_get_role()
97 	dev = class_find_device(role_class, NULL, con->endpoint[ep],  in usb_role_switch_match()
100 	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);  in usb_role_switch_match()
104  * usb_role_switch_get - Find USB role switch linked with the caller
107  * Finds and returns role switch linked with @dev. The reference count for the
108  * found switch is incremented.
114 	sw = device_connection_find_match(dev, "usb-role-switch", NULL,  in usb_role_switch_get()
118 		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));  in usb_role_switch_get()
125  * usb_role_switch_put - Release handle to a switch
126  * @sw: USB Role Switch
133 		module_put(sw->dev.parent->driver->owner);  in usb_role_switch_put()
134 		put_device(&sw->dev);  in usb_role_switch_put()
145 	if (sw->allow_userspace_control)  in usb_role_switch_is_visible()
146 		return attr->mode;  in usb_role_switch_is_visible()
161 	enum usb_role role = usb_role_switch_get_role(sw);  in role_show()  local
163 	return sprintf(buf, "%s\n", usb_roles[role]);  in role_show()
176 		/* Extra check if the user wants to disable the switch */  in role_store()
179 			return -EINVAL;  in role_store()
188 static DEVICE_ATTR_RW(role);
232  * usb_role_switch_register - Register USB Role Switch
233  * @parent: Parent device for the switch
234  * @desc: Description of the switch
236  * USB Role Switch is a device capable or choosing the role for USB connector.
237  * On platforms where the USB controller is dual-role capable, the controller
238  * driver will need to register the switch. On platforms where the USB host and
239  * USB device controllers behind the connector are separate, there will be a
240  * mux, and the driver for that mux will need to register the switch.
242  * Returns handle to a new role switch or ERR_PTR. The content of @desc is
252 	if (!desc || !desc->set)  in usb_role_switch_register()
253 		return ERR_PTR(-EINVAL);  in usb_role_switch_register()
257 		return ERR_PTR(-ENOMEM);  in usb_role_switch_register()
259 	mutex_init(&sw->lock);  in usb_role_switch_register()
261 	sw->allow_userspace_control = desc->allow_userspace_control;  in usb_role_switch_register()
262 	sw->usb2_port = desc->usb2_port;  in usb_role_switch_register()
263 	sw->usb3_port = desc->usb3_port;  in usb_role_switch_register()
264 	sw->udc = desc->udc;  in usb_role_switch_register()
265 	sw->set = desc->set;  in usb_role_switch_register()
266 	sw->get = desc->get;  in usb_role_switch_register()
268 	sw->dev.parent = parent;  in usb_role_switch_register()
269 	sw->dev.class = role_class;  in usb_role_switch_register()
270 	sw->dev.type = &usb_role_dev_type;  in usb_role_switch_register()
271 	dev_set_name(&sw->dev, "%s-role-switch", dev_name(parent));  in usb_role_switch_register()
273 	ret = device_register(&sw->dev);  in usb_role_switch_register()
275 		put_device(&sw->dev);  in usb_role_switch_register()
286  * usb_role_switch_unregister - Unregsiter USB Role Switch
287  * @sw: USB Role Switch
289  * Unregister switch that was registered with usb_role_switch_register().
294 		device_unregister(&sw->dev);  in usb_role_switch_unregister()
314 MODULE_DESCRIPTION("USB Role Class");