projects/linux·blob v5.5-rc3 · refs

231 lines · 5.8 KiB

1// SPDX-License-Identifier: GPL-2.0
2/**
3 * Device connections
4 *
5 * Copyright (C) 2018 Intel Corporation
6 * Author: Heikki Krogerus <[email protected]>
7 */
8
9#include <linux/device.h>
10#include <linux/property.h>
11
12static DEFINE_MUTEX(devcon_lock);
13static LIST_HEAD(devcon_list);
14
15static void *
16fwnode_graph_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
17 void *data, devcon_match_fn_t match)
18{
19 struct device_connection con = { .id = con_id };
20 struct fwnode_handle *ep;
21 void *ret;
22
23 fwnode_graph_for_each_endpoint(fwnode, ep) {
24 con.fwnode = fwnode_graph_get_remote_port_parent(ep);
25 if (!fwnode_device_is_available(con.fwnode))
26 continue;
27
28 ret = match(&con, -1, data);
29 fwnode_handle_put(con.fwnode);
30 if (ret) {
31 fwnode_handle_put(ep);
32 return ret;
33 }
34 }
35 return NULL;
36}
37
38static void *
39fwnode_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
40 void *data, devcon_match_fn_t match)
41{
42 struct device_connection con = { };
43 void *ret;
44 int i;
45
46 for (i = 0; ; i++) {
47 con.fwnode = fwnode_find_reference(fwnode, con_id, i);
48 if (IS_ERR(con.fwnode))
49 break;
50
51 ret = match(&con, -1, data);
52 fwnode_handle_put(con.fwnode);
53 if (ret)
54 return ret;
55 }
56
57 return NULL;
58}
59
60/**
61 * fwnode_connection_find_match - Find connection from a device node
62 * @fwnode: Device node with the connection
63 * @con_id: Identifier for the connection
64 * @data: Data for the match function
65 * @match: Function to check and convert the connection description
66 *
67 * Find a connection with unique identifier @con_id between @fwnode and another
68 * device node. @match will be used to convert the connection description to
69 * data the caller is expecting to be returned.
70 */
71void *fwnode_connection_find_match(struct fwnode_handle *fwnode,
72 const char *con_id, void *data,
73 devcon_match_fn_t match)
74{
75 void *ret;
76
77 if (!fwnode || !match)
78 return NULL;
79
80 ret = fwnode_graph_devcon_match(fwnode, con_id, data, match);
81 if (ret)
82 return ret;
83
84 return fwnode_devcon_match(fwnode, con_id, data, match);
85}
86EXPORT_SYMBOL_GPL(fwnode_connection_find_match);
87
88/**
89 * device_connection_find_match - Find physical connection to a device
90 * @dev: Device with the connection
91 * @con_id: Identifier for the connection
92 * @data: Data for the match function
93 * @match: Function to check and convert the connection description
94 *
95 * Find a connection with unique identifier @con_id between @dev and another
96 * device. @match will be used to convert the connection description to data the
97 * caller is expecting to be returned.
98 */
99void *device_connection_find_match(struct device *dev, const char *con_id,
100 void *data, devcon_match_fn_t match)
101{
102 struct fwnode_handle *fwnode = dev_fwnode(dev);
103 const char *devname = dev_name(dev);
104 struct device_connection *con;
105 void *ret = NULL;
106 int ep;
107
108 if (!match)
109 return NULL;
110
111 ret = fwnode_connection_find_match(fwnode, con_id, data, match);
112 if (ret)
113 return ret;
114
115 mutex_lock(&devcon_lock);
116
117 list_for_each_entry(con, &devcon_list, list) {
118 ep = match_string(con->endpoint, 2, devname);
119 if (ep < 0)
120 continue;
121
122 if (con_id && strcmp(con->id, con_id))
123 continue;
124
125 ret = match(con, !ep, data);
126 if (ret)
127 break;
128 }
129
130 mutex_unlock(&devcon_lock);
131
132 return ret;
133}
134EXPORT_SYMBOL_GPL(device_connection_find_match);
135
136extern struct bus_type platform_bus_type;
137extern struct bus_type pci_bus_type;
138extern struct bus_type i2c_bus_type;
139extern struct bus_type spi_bus_type;
140
141static struct bus_type *generic_match_buses[] = {
142 &platform_bus_type,
143#ifdef CONFIG_PCI
144 &pci_bus_type,
145#endif
146#ifdef CONFIG_I2C
147 &i2c_bus_type,
148#endif
149#ifdef CONFIG_SPI_MASTER
150 &spi_bus_type,
151#endif
152 NULL,
153};
154
155static void *device_connection_fwnode_match(struct device_connection *con)
156{
157 struct bus_type *bus;
158 struct device *dev;
159
160 for (bus = generic_match_buses[0]; bus; bus++) {
161 dev = bus_find_device_by_fwnode(bus, con->fwnode);
162 if (dev && !strncmp(dev_name(dev), con->id, strlen(con->id)))
163 return dev;
164
165 put_device(dev);
166 }
167 return NULL;
168}
169
170/* This tries to find the device from the most common bus types by name. */
171static void *generic_match(struct device_connection *con, int ep, void *data)
172{
173 struct bus_type *bus;
174 struct device *dev;
175
176 if (con->fwnode)
177 return device_connection_fwnode_match(con);
178
179 for (bus = generic_match_buses[0]; bus; bus++) {
180 dev = bus_find_device_by_name(bus, NULL, con->endpoint[ep]);
181 if (dev)
182 return dev;
183 }
184
185 /*
186 * We only get called if a connection was found, tell the caller to
187 * wait for the other device to show up.
188 */
189 return ERR_PTR(-EPROBE_DEFER);
190}
191
192/**
193 * device_connection_find - Find two devices connected together
194 * @dev: Device with the connection
195 * @con_id: Identifier for the connection
196 *
197 * Find a connection with unique identifier @con_id between @dev and
198 * another device. On success returns handle to the device that is connected
199 * to @dev, with the reference count for the found device incremented. Returns
200 * NULL if no matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a
201 * connection was found but the other device has not been enumerated yet.
202 */
203struct device *device_connection_find(struct device *dev, const char *con_id)
204{
205 return device_connection_find_match(dev, con_id, NULL, generic_match);
206}
207EXPORT_SYMBOL_GPL(device_connection_find);
208
209/**
210 * device_connection_add - Register a connection description
211 * @con: The connection description to be registered
212 */
213void device_connection_add(struct device_connection *con)
214{
215 mutex_lock(&devcon_lock);
216 list_add_tail(&con->list, &devcon_list);
217 mutex_unlock(&devcon_lock);
218}
219EXPORT_SYMBOL_GPL(device_connection_add);
220
221/**
222 * device_connections_remove - Unregister connection description
223 * @con: The connection description to be unregistered
224 */
225void device_connection_remove(struct device_connection *con)
226{
227 mutex_lock(&devcon_lock);
228 list_del(&con->list);
229 mutex_unlock(&devcon_lock);
230}
231EXPORT_SYMBOL_GPL(device_connection_remove);