1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ulpi.c - USB ULPI PHY bus
4 *
5 * Copyright (C) 2015 Intel Corporation
6 *
7 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
8 */
9
10#include <linux/ulpi/interface.h>
11#include <linux/ulpi/driver.h>
12#include <linux/ulpi/regs.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/acpi.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/clk/clk-conf.h>
19
20/* -------------------------------------------------------------------------- */
21
22int ulpi_read(struct ulpi *ulpi, u8 addr)
23{
24	return ulpi->ops->read(ulpi->dev.parent, addr);
25}
26EXPORT_SYMBOL_GPL(ulpi_read);
27
28int ulpi_write(struct ulpi *ulpi, u8 addr, u8 val)
29{
30	return ulpi->ops->write(ulpi->dev.parent, addr, val);
31}
32EXPORT_SYMBOL_GPL(ulpi_write);
33
34/* -------------------------------------------------------------------------- */
35
36static int ulpi_match(struct device *dev, struct device_driver *driver)
37{
38	struct ulpi_driver *drv = to_ulpi_driver(driver);
39	struct ulpi *ulpi = to_ulpi_dev(dev);
40	const struct ulpi_device_id *id;
41
42	/*
43	 * Some ULPI devices don't have a vendor id
44	 * or provide an id_table so rely on OF match.
45	 */
46	if (ulpi->id.vendor == 0 || !drv->id_table)
47		return of_driver_match_device(dev, driver);
48
49	for (id = drv->id_table; id->vendor; id++)
50		if (id->vendor == ulpi->id.vendor &&
51		    id->product == ulpi->id.product)
52			return 1;
53
54	return 0;
55}
56
57static int ulpi_uevent(struct device *dev, struct kobj_uevent_env *env)
58{
59	struct ulpi *ulpi = to_ulpi_dev(dev);
60	int ret;
61
62	ret = of_device_uevent_modalias(dev, env);
63	if (ret != -ENODEV)
64		return ret;
65
66	if (add_uevent_var(env, "MODALIAS=ulpi:v%04xp%04x",
67			   ulpi->id.vendor, ulpi->id.product))
68		return -ENOMEM;
69	return 0;
70}
71
72static int ulpi_probe(struct device *dev)
73{
74	struct ulpi_driver *drv = to_ulpi_driver(dev->driver);
75	int ret;
76
77	ret = of_clk_set_defaults(dev->of_node, false);
78	if (ret < 0)
79		return ret;
80
81	return drv->probe(to_ulpi_dev(dev));
82}
83
84static int ulpi_remove(struct device *dev)
85{
86	struct ulpi_driver *drv = to_ulpi_driver(dev->driver);
87
88	if (drv->remove)
89		drv->remove(to_ulpi_dev(dev));
90
91	return 0;
92}
93
94static struct bus_type ulpi_bus = {
95	.name = "ulpi",
96	.match = ulpi_match,
97	.uevent = ulpi_uevent,
98	.probe = ulpi_probe,
99	.remove = ulpi_remove,
100};
101
102/* -------------------------------------------------------------------------- */
103
104static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
105			     char *buf)
106{
107	int len;
108	struct ulpi *ulpi = to_ulpi_dev(dev);
109
110	len = of_device_modalias(dev, buf, PAGE_SIZE);
111	if (len != -ENODEV)
112		return len;
113
114	return sprintf(buf, "ulpi:v%04xp%04x\n",
115		       ulpi->id.vendor, ulpi->id.product);
116}
117static DEVICE_ATTR_RO(modalias);
118
119static struct attribute *ulpi_dev_attrs[] = {
120	&dev_attr_modalias.attr,
121	NULL
122};
123
124static struct attribute_group ulpi_dev_attr_group = {
125	.attrs = ulpi_dev_attrs,
126};
127
128static const struct attribute_group *ulpi_dev_attr_groups[] = {
129	&ulpi_dev_attr_group,
130	NULL
131};
132
133static void ulpi_dev_release(struct device *dev)
134{
135	of_node_put(dev->of_node);
136	kfree(to_ulpi_dev(dev));
137}
138
139static const struct device_type ulpi_dev_type = {
140	.name = "ulpi_device",
141	.groups = ulpi_dev_attr_groups,
142	.release = ulpi_dev_release,
143};
144
145/* -------------------------------------------------------------------------- */
146
147/**
148 * ulpi_register_driver - register a driver with the ULPI bus
149 * @drv: driver being registered
150 * @module: ends up being THIS_MODULE
151 *
152 * Registers a driver with the ULPI bus.
153 */
154int __ulpi_register_driver(struct ulpi_driver *drv, struct module *module)
155{
156	if (!drv->probe)
157		return -EINVAL;
158
159	drv->driver.owner = module;
160	drv->driver.bus = &ulpi_bus;
161
162	return driver_register(&drv->driver);
163}
164EXPORT_SYMBOL_GPL(__ulpi_register_driver);
165
166/**
167 * ulpi_unregister_driver - unregister a driver with the ULPI bus
168 * @drv: driver to unregister
169 *
170 * Unregisters a driver with the ULPI bus.
171 */
172void ulpi_unregister_driver(struct ulpi_driver *drv)
173{
174	driver_unregister(&drv->driver);
175}
176EXPORT_SYMBOL_GPL(ulpi_unregister_driver);
177
178/* -------------------------------------------------------------------------- */
179
180static int ulpi_of_register(struct ulpi *ulpi)
181{
182	struct device_node *np = NULL, *child;
183	struct device *parent;
184
185	/* Find a ulpi bus underneath the parent or the grandparent */
186	parent = ulpi->dev.parent;
187	if (parent->of_node)
188		np = of_get_child_by_name(parent->of_node, "ulpi");
189	else if (parent->parent && parent->parent->of_node)
190		np = of_get_child_by_name(parent->parent->of_node, "ulpi");
191	if (!np)
192		return 0;
193
194	child = of_get_next_available_child(np, NULL);
195	of_node_put(np);
196	if (!child)
197		return -EINVAL;
198
199	ulpi->dev.of_node = child;
200
201	return 0;
202}
203
204static int ulpi_read_id(struct ulpi *ulpi)
205{
206	int ret;
207
208	/* Test the interface */
209	ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
210	if (ret < 0)
211		goto err;
212
213	ret = ulpi_read(ulpi, ULPI_SCRATCH);
214	if (ret < 0)
215		return ret;
216
217	if (ret != 0xaa)
218		goto err;
219
220	ulpi->id.vendor = ulpi_read(ulpi, ULPI_VENDOR_ID_LOW);
221	ulpi->id.vendor |= ulpi_read(ulpi, ULPI_VENDOR_ID_HIGH) << 8;
222
223	ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
224	ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;
225
226	/* Some ULPI devices don't have a vendor id so rely on OF match */
227	if (ulpi->id.vendor == 0)
228		goto err;
229
230	request_module("ulpi:v%04xp%04x", ulpi->id.vendor, ulpi->id.product);
231	return 0;
232err:
233	of_device_request_module(&ulpi->dev);
234	return 0;
235}
236
237static int ulpi_register(struct device *dev, struct ulpi *ulpi)
238{
239	int ret;
240
241	ulpi->dev.parent = dev; /* needed early for ops */
242	ulpi->dev.bus = &ulpi_bus;
243	ulpi->dev.type = &ulpi_dev_type;
244	dev_set_name(&ulpi->dev, "%s.ulpi", dev_name(dev));
245
246	ACPI_COMPANION_SET(&ulpi->dev, ACPI_COMPANION(dev));
247
248	ret = ulpi_of_register(ulpi);
249	if (ret)
250		return ret;
251
252	ret = ulpi_read_id(ulpi);
253	if (ret) {
254		of_node_put(ulpi->dev.of_node);
255		return ret;
256	}
257
258	ret = device_register(&ulpi->dev);
259	if (ret) {
260		put_device(&ulpi->dev);
261		return ret;
262	}
263
264	dev_dbg(&ulpi->dev, "registered ULPI PHY: vendor %04x, product %04x\n",
265		ulpi->id.vendor, ulpi->id.product);
266
267	return 0;
268}
269
270/**
271 * ulpi_register_interface - instantiate new ULPI device
272 * @dev: USB controller's device interface
273 * @ops: ULPI register access
274 *
275 * Allocates and registers a ULPI device and an interface for it. Called from
276 * the USB controller that provides the ULPI interface.
277 */
278struct ulpi *ulpi_register_interface(struct device *dev,
279				     const struct ulpi_ops *ops)
280{
281	struct ulpi *ulpi;
282	int ret;
283
284	ulpi = kzalloc(sizeof(*ulpi), GFP_KERNEL);
285	if (!ulpi)
286		return ERR_PTR(-ENOMEM);
287
288	ulpi->ops = ops;
289
290	ret = ulpi_register(dev, ulpi);
291	if (ret) {
292		kfree(ulpi);
293		return ERR_PTR(ret);
294	}
295
296	return ulpi;
297}
298EXPORT_SYMBOL_GPL(ulpi_register_interface);
299
300/**
301 * ulpi_unregister_interface - unregister ULPI interface
302 * @ulpi: struct ulpi_interface
303 *
304 * Unregisters a ULPI device and it's interface that was created with
305 * ulpi_create_interface().
306 */
307void ulpi_unregister_interface(struct ulpi *ulpi)
308{
309	device_unregister(&ulpi->dev);
310}
311EXPORT_SYMBOL_GPL(ulpi_unregister_interface);
312
313/* -------------------------------------------------------------------------- */
314
315static int __init ulpi_init(void)
316{
317	return bus_register(&ulpi_bus);
318}
319subsys_initcall(ulpi_init);
320
321static void __exit ulpi_exit(void)
322{
323	bus_unregister(&ulpi_bus);
324}
325module_exit(ulpi_exit);
326
327MODULE_AUTHOR("Intel Corporation");
328MODULE_LICENSE("GPL v2");
329MODULE_DESCRIPTION("USB ULPI PHY bus");
330