1 // SPDX-License-Identifier: GPL-2.0
5  * The DP AUX bus is used for devices that are connected over a DisplayPort
6  * AUX bus. The device on the far side of the bus is referred to as an
9  * There is only one device connected to the DP AUX bus: an eDP panel.
11  * platform devices, putting them under the DP AUX bus allows the panel driver
12  * to perform transactions on that bus.
31  * dp_aux_ep_match() - The match function for the dp_aux_bus.
41 	return !!of_match_device(drv->of_match_table, dev);  in dp_aux_ep_match()
45  * dp_aux_ep_probe() - The probe function for the dp_aux_bus.
54 	struct dp_aux_ep_driver *aux_ep_drv = to_dp_aux_ep_drv(dev->driver);  in dp_aux_ep_probe()
64 	ret = aux_ep_drv->probe(aux_ep);  in dp_aux_ep_probe()
68 	if (aux_ep_with_data->done_probing) {  in dp_aux_ep_probe()
69 		ret = aux_ep_with_data->done_probing(aux_ep->aux);  in dp_aux_ep_probe()
73 			 * -EPROBE_DEFER to us. If it does, we treat it as an  in dp_aux_ep_probe()
74 			 * error. Passing it on as-is would cause the _panel_  in dp_aux_ep_probe()
77 			if (ret == -EPROBE_DEFER) {  in dp_aux_ep_probe()
80 				ret = -EINVAL;  in dp_aux_ep_probe()
88 	if (aux_ep_drv->remove)  in dp_aux_ep_probe()
89 		aux_ep_drv->remove(aux_ep);  in dp_aux_ep_probe()
97  * dp_aux_ep_remove() - The remove function for the dp_aux_bus.
104 	struct dp_aux_ep_driver *aux_ep_drv = to_dp_aux_ep_drv(dev->driver);  in dp_aux_ep_remove()
107 	if (aux_ep_drv->remove)  in dp_aux_ep_remove()
108 		aux_ep_drv->remove(aux_ep);  in dp_aux_ep_remove()
113  * dp_aux_ep_shutdown() - The shutdown function for the dp_aux_bus.
122 	if (!dev->driver)  in dp_aux_ep_shutdown()
125 	aux_ep_drv = to_dp_aux_ep_drv(dev->driver);  in dp_aux_ep_shutdown()
126 	if (aux_ep_drv->shutdown)  in dp_aux_ep_shutdown()
127 		aux_ep_drv->shutdown(to_dp_aux_ep_dev(dev));  in dp_aux_ep_shutdown()
131 	.name		= "dp-aux",
152  * dp_aux_ep_dev_release() - Free memory for the dp_aux_ep device
176  * of_dp_aux_ep_destroy() - Destroy an DP AUX endpoint device
181  * is called for _all_ of the child devices of the device providing the AUX bus.
193 	struct device_node *np = dev->of_node;  in of_dp_aux_ep_destroy()
195 	if (dev->bus != &dp_aux_bus_type)  in of_dp_aux_ep_destroy()
210  * of_dp_aux_depopulate_bus() - Undo of_dp_aux_populate_bus
218 	device_for_each_child_reverse(aux->dev, NULL, of_dp_aux_ep_destroy);  in of_dp_aux_depopulate_bus()
223  * of_dp_aux_populate_bus() - Populate the endpoint device on the DP AUX
228  *                function will return -ENODEV.
231  * "aux-bus" node of the device providing the AUX channel (AKA aux->dev).
234  * our sub-device will have finished probing. It should be noted that if our
235  * sub-device returns -EPROBE_DEFER or is probing asynchronously for some
237  * sub-device will _not_ have actually probed successfully yet.
240  * when our sub device finishes probing. Our sub device is expected to be an
244  * will be called when our sub-device finishes probing.
250  * Return: 0 if no error or negative error code; returns -ENODEV if there are
257 	struct device_node *bus = NULL, *np = NULL;  in of_dp_aux_populate_bus()  local
263 	WARN_ON_ONCE(!aux->ddc.algo);  in of_dp_aux_populate_bus()
265 	if (!aux->dev->of_node)  in of_dp_aux_populate_bus()
266 		return -ENODEV;  in of_dp_aux_populate_bus()
267 	bus = of_get_child_by_name(aux->dev->of_node, "aux-bus");  in of_dp_aux_populate_bus()
268 	if (!bus)  in of_dp_aux_populate_bus()
269 		return -ENODEV;  in of_dp_aux_populate_bus()
271 	np = of_get_next_available_child(bus, NULL);  in of_dp_aux_populate_bus()
272 	of_node_put(bus);  in of_dp_aux_populate_bus()
274 		return -ENODEV;  in of_dp_aux_populate_bus()
277 		dev_err(aux->dev, "DP AUX EP device already populated\n");  in of_dp_aux_populate_bus()
278 		ret = -EINVAL;  in of_dp_aux_populate_bus()
284 		ret = -ENOMEM;  in of_dp_aux_populate_bus()
288 	aux_ep_with_data->done_probing = done_probing;  in of_dp_aux_populate_bus()
290 	aux_ep = &aux_ep_with_data->aux_ep;  in of_dp_aux_populate_bus()
291 	aux_ep->aux = aux;  in of_dp_aux_populate_bus()
292 	aux_ep->dev.parent = aux->dev;  in of_dp_aux_populate_bus()
293 	aux_ep->dev.bus = &dp_aux_bus_type;  in of_dp_aux_populate_bus()
294 	aux_ep->dev.type = &dp_aux_device_type_type;  in of_dp_aux_populate_bus()
295 	aux_ep->dev.of_node = of_node_get(np);  in of_dp_aux_populate_bus()
296 	dev_set_name(&aux_ep->dev, "aux-%s", dev_name(aux->dev));  in of_dp_aux_populate_bus()
298 	ret = device_register(&aux_ep->dev);  in of_dp_aux_populate_bus()
300 		dev_err(aux->dev, "Failed to create AUX EP for %pOF: %d\n", np, ret);  in of_dp_aux_populate_bus()
306 		put_device(&aux_ep->dev);  in of_dp_aux_populate_bus()
329  * devm_of_dp_aux_populate_bus() - devm wrapper for of_dp_aux_populate_bus()
333  *                function will return -ENODEV.
335  * Handles freeing w/ devm on the device "aux->dev".
337  * Return: 0 if no error or negative error code; returns -ENODEV if there are
350 	return devm_add_action_or_reset(aux->dev,  in devm_of_dp_aux_populate_bus()
357 	drv->driver.owner = owner;  in __dp_aux_dp_driver_register()
358 	drv->driver.bus = &dp_aux_bus_type;  in __dp_aux_dp_driver_register()
360 	return driver_register(&drv->driver);  in __dp_aux_dp_driver_register()
366 	driver_unregister(&drv->driver);  in dp_aux_dp_driver_unregister()
390 MODULE_DESCRIPTION("DRM DisplayPort AUX bus");