xref: /openbmc/linux/drivers/usb/common/ulpi.c (revision d9565bf4)
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 
22 int ulpi_read(struct ulpi *ulpi, u8 addr)
23 {
24 	return ulpi->ops->read(ulpi->dev.parent, addr);
25 }
26 EXPORT_SYMBOL_GPL(ulpi_read);
27 
28 int ulpi_write(struct ulpi *ulpi, u8 addr, u8 val)
29 {
30 	return ulpi->ops->write(ulpi->dev.parent, addr, val);
31 }
32 EXPORT_SYMBOL_GPL(ulpi_write);
33 
34 /* -------------------------------------------------------------------------- */
35 
36 static 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 
57 static 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 
72 static 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 
84 static void 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 
92 static struct bus_type ulpi_bus = {
93 	.name = "ulpi",
94 	.match = ulpi_match,
95 	.uevent = ulpi_uevent,
96 	.probe = ulpi_probe,
97 	.remove = ulpi_remove,
98 };
99 
100 /* -------------------------------------------------------------------------- */
101 
102 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
103 			     char *buf)
104 {
105 	int len;
106 	struct ulpi *ulpi = to_ulpi_dev(dev);
107 
108 	len = of_device_modalias(dev, buf, PAGE_SIZE);
109 	if (len != -ENODEV)
110 		return len;
111 
112 	return sprintf(buf, "ulpi:v%04xp%04x\n",
113 		       ulpi->id.vendor, ulpi->id.product);
114 }
115 static DEVICE_ATTR_RO(modalias);
116 
117 static struct attribute *ulpi_dev_attrs[] = {
118 	&dev_attr_modalias.attr,
119 	NULL
120 };
121 
122 static const struct attribute_group ulpi_dev_attr_group = {
123 	.attrs = ulpi_dev_attrs,
124 };
125 
126 static const struct attribute_group *ulpi_dev_attr_groups[] = {
127 	&ulpi_dev_attr_group,
128 	NULL
129 };
130 
131 static void ulpi_dev_release(struct device *dev)
132 {
133 	kfree(to_ulpi_dev(dev));
134 }
135 
136 static const struct device_type ulpi_dev_type = {
137 	.name = "ulpi_device",
138 	.groups = ulpi_dev_attr_groups,
139 	.release = ulpi_dev_release,
140 };
141 
142 /* -------------------------------------------------------------------------- */
143 
144 /**
145  * __ulpi_register_driver - register a driver with the ULPI bus
146  * @drv: driver being registered
147  * @module: ends up being THIS_MODULE
148  *
149  * Registers a driver with the ULPI bus.
150  */
151 int __ulpi_register_driver(struct ulpi_driver *drv, struct module *module)
152 {
153 	if (!drv->probe)
154 		return -EINVAL;
155 
156 	drv->driver.owner = module;
157 	drv->driver.bus = &ulpi_bus;
158 
159 	return driver_register(&drv->driver);
160 }
161 EXPORT_SYMBOL_GPL(__ulpi_register_driver);
162 
163 /**
164  * ulpi_unregister_driver - unregister a driver with the ULPI bus
165  * @drv: driver to unregister
166  *
167  * Unregisters a driver with the ULPI bus.
168  */
169 void ulpi_unregister_driver(struct ulpi_driver *drv)
170 {
171 	driver_unregister(&drv->driver);
172 }
173 EXPORT_SYMBOL_GPL(ulpi_unregister_driver);
174 
175 /* -------------------------------------------------------------------------- */
176 
177 static int ulpi_of_register(struct ulpi *ulpi)
178 {
179 	struct device_node *np = NULL, *child;
180 	struct device *parent;
181 
182 	/* Find a ulpi bus underneath the parent or the grandparent */
183 	parent = ulpi->dev.parent;
184 	if (parent->of_node)
185 		np = of_get_child_by_name(parent->of_node, "ulpi");
186 	else if (parent->parent && parent->parent->of_node)
187 		np = of_get_child_by_name(parent->parent->of_node, "ulpi");
188 	if (!np)
189 		return 0;
190 
191 	child = of_get_next_available_child(np, NULL);
192 	of_node_put(np);
193 	if (!child)
194 		return -EINVAL;
195 
196 	ulpi->dev.of_node = child;
197 
198 	return 0;
199 }
200 
201 static int ulpi_read_id(struct ulpi *ulpi)
202 {
203 	int ret;
204 
205 	/* Test the interface */
206 	ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
207 	if (ret < 0)
208 		goto err;
209 
210 	ret = ulpi_read(ulpi, ULPI_SCRATCH);
211 	if (ret < 0)
212 		return ret;
213 
214 	if (ret != 0xaa)
215 		goto err;
216 
217 	ulpi->id.vendor = ulpi_read(ulpi, ULPI_VENDOR_ID_LOW);
218 	ulpi->id.vendor |= ulpi_read(ulpi, ULPI_VENDOR_ID_HIGH) << 8;
219 
220 	ulpi->id.product = ulpi_read(ulpi, ULPI_PRODUCT_ID_LOW);
221 	ulpi->id.product |= ulpi_read(ulpi, ULPI_PRODUCT_ID_HIGH) << 8;
222 
223 	/* Some ULPI devices don't have a vendor id so rely on OF match */
224 	if (ulpi->id.vendor == 0)
225 		goto err;
226 
227 	request_module("ulpi:v%04xp%04x", ulpi->id.vendor, ulpi->id.product);
228 	return 0;
229 err:
230 	of_device_request_module(&ulpi->dev);
231 	return 0;
232 }
233 
234 static int ulpi_register(struct device *dev, struct ulpi *ulpi)
235 {
236 	int ret;
237 
238 	ulpi->dev.parent = dev; /* needed early for ops */
239 	ulpi->dev.bus = &ulpi_bus;
240 	ulpi->dev.type = &ulpi_dev_type;
241 	dev_set_name(&ulpi->dev, "%s.ulpi", dev_name(dev));
242 
243 	ACPI_COMPANION_SET(&ulpi->dev, ACPI_COMPANION(dev));
244 
245 	ret = ulpi_of_register(ulpi);
246 	if (ret)
247 		return ret;
248 
249 	ret = ulpi_read_id(ulpi);
250 	if (ret)
251 		return ret;
252 
253 	ret = device_register(&ulpi->dev);
254 	if (ret)
255 		return ret;
256 
257 	dev_dbg(&ulpi->dev, "registered ULPI PHY: vendor %04x, product %04x\n",
258 		ulpi->id.vendor, ulpi->id.product);
259 
260 	return 0;
261 }
262 
263 /**
264  * ulpi_register_interface - instantiate new ULPI device
265  * @dev: USB controller's device interface
266  * @ops: ULPI register access
267  *
268  * Allocates and registers a ULPI device and an interface for it. Called from
269  * the USB controller that provides the ULPI interface.
270  */
271 struct ulpi *ulpi_register_interface(struct device *dev,
272 				     const struct ulpi_ops *ops)
273 {
274 	struct ulpi *ulpi;
275 	int ret;
276 
277 	ulpi = kzalloc(sizeof(*ulpi), GFP_KERNEL);
278 	if (!ulpi)
279 		return ERR_PTR(-ENOMEM);
280 
281 	ulpi->ops = ops;
282 
283 	ret = ulpi_register(dev, ulpi);
284 	if (ret) {
285 		kfree(ulpi);
286 		return ERR_PTR(ret);
287 	}
288 
289 	return ulpi;
290 }
291 EXPORT_SYMBOL_GPL(ulpi_register_interface);
292 
293 /**
294  * ulpi_unregister_interface - unregister ULPI interface
295  * @ulpi: struct ulpi_interface
296  *
297  * Unregisters a ULPI device and it's interface that was created with
298  * ulpi_create_interface().
299  */
300 void ulpi_unregister_interface(struct ulpi *ulpi)
301 {
302 	of_node_put(ulpi->dev.of_node);
303 	device_unregister(&ulpi->dev);
304 }
305 EXPORT_SYMBOL_GPL(ulpi_unregister_interface);
306 
307 /* -------------------------------------------------------------------------- */
308 
309 static int __init ulpi_init(void)
310 {
311 	return bus_register(&ulpi_bus);
312 }
313 subsys_initcall(ulpi_init);
314 
315 static void __exit ulpi_exit(void)
316 {
317 	bus_unregister(&ulpi_bus);
318 }
319 module_exit(ulpi_exit);
320 
321 MODULE_AUTHOR("Intel Corporation");
322 MODULE_LICENSE("GPL v2");
323 MODULE_DESCRIPTION("USB ULPI PHY bus");
324