1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * v4l2-i2c - I2C helpers for Video4Linux2
4  */
5 
6 #include <linux/i2c.h>
7 #include <linux/module.h>
8 #include <media/v4l2-common.h>
9 #include <media/v4l2-device.h>
10 
11 void v4l2_i2c_subdev_unregister(struct v4l2_subdev *sd)
12 {
13 	struct i2c_client *client = v4l2_get_subdevdata(sd);
14 
15 	/*
16 	 * We need to unregister the i2c client
17 	 * explicitly. We cannot rely on
18 	 * i2c_del_adapter to always unregister
19 	 * clients for us, since if the i2c bus is a
20 	 * platform bus, then it is never deleted.
21 	 *
22 	 * Device tree or ACPI based devices must not
23 	 * be unregistered as they have not been
24 	 * registered by us, and would not be
25 	 * re-created by just probing the V4L2 driver.
26 	 */
27 	if (client && !client->dev.of_node && !client->dev.fwnode)
28 		i2c_unregister_device(client);
29 }
30 
31 void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd,
32 			      struct i2c_client *client,
33 			      const char *devname, const char *postfix)
34 {
35 	if (!devname)
36 		devname = client->dev.driver->name;
37 	if (!postfix)
38 		postfix = "";
39 
40 	snprintf(sd->name, sizeof(sd->name), "%s%s %d-%04x", devname, postfix,
41 		 i2c_adapter_id(client->adapter), client->addr);
42 }
43 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_set_name);
44 
45 void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
46 			  const struct v4l2_subdev_ops *ops)
47 {
48 	v4l2_subdev_init(sd, ops);
49 	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
50 	/* the owner is the same as the i2c_client's driver owner */
51 	sd->owner = client->dev.driver->owner;
52 	sd->dev = &client->dev;
53 	/* i2c_client and v4l2_subdev point to one another */
54 	v4l2_set_subdevdata(sd, client);
55 	i2c_set_clientdata(client, sd);
56 	v4l2_i2c_subdev_set_name(sd, client, NULL, NULL);
57 }
58 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
59 
60 /* Load an i2c sub-device. */
61 struct v4l2_subdev
62 *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
63 			   struct i2c_adapter *adapter,
64 			   struct i2c_board_info *info,
65 			   const unsigned short *probe_addrs)
66 {
67 	struct v4l2_subdev *sd = NULL;
68 	struct i2c_client *client;
69 
70 	if (!v4l2_dev)
71 		return NULL;
72 
73 	request_module(I2C_MODULE_PREFIX "%s", info->type);
74 
75 	/* Create the i2c client */
76 	if (info->addr == 0 && probe_addrs)
77 		client = i2c_new_scanned_device(adapter, info, probe_addrs,
78 						NULL);
79 	else
80 		client = i2c_new_client_device(adapter, info);
81 
82 	/*
83 	 * Note: by loading the module first we are certain that c->driver
84 	 * will be set if the driver was found. If the module was not loaded
85 	 * first, then the i2c core tries to delay-load the module for us,
86 	 * and then c->driver is still NULL until the module is finally
87 	 * loaded. This delay-load mechanism doesn't work if other drivers
88 	 * want to use the i2c device, so explicitly loading the module
89 	 * is the best alternative.
90 	 */
91 	if (!i2c_client_has_driver(client))
92 		goto error;
93 
94 	/* Lock the module so we can safely get the v4l2_subdev pointer */
95 	if (!try_module_get(client->dev.driver->owner))
96 		goto error;
97 	sd = i2c_get_clientdata(client);
98 
99 	/*
100 	 * Register with the v4l2_device which increases the module's
101 	 * use count as well.
102 	 */
103 	if (v4l2_device_register_subdev(v4l2_dev, sd))
104 		sd = NULL;
105 	/* Decrease the module use count to match the first try_module_get. */
106 	module_put(client->dev.driver->owner);
107 
108 error:
109 	/*
110 	 * If we have a client but no subdev, then something went wrong and
111 	 * we must unregister the client.
112 	 */
113 	if (!IS_ERR(client) && !sd)
114 		i2c_unregister_device(client);
115 	return sd;
116 }
117 EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);
118 
119 struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
120 					struct i2c_adapter *adapter,
121 					const char *client_type,
122 					u8 addr,
123 					const unsigned short *probe_addrs)
124 {
125 	struct i2c_board_info info;
126 
127 	/*
128 	 * Setup the i2c board info with the device type and
129 	 * the device address.
130 	 */
131 	memset(&info, 0, sizeof(info));
132 	strscpy(info.type, client_type, sizeof(info.type));
133 	info.addr = addr;
134 
135 	return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info,
136 					 probe_addrs);
137 }
138 EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);
139 
140 /* Return i2c client address of v4l2_subdev. */
141 unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
142 {
143 	struct i2c_client *client = v4l2_get_subdevdata(sd);
144 
145 	return client ? client->addr : I2C_CLIENT_END;
146 }
147 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);
148 
149 /*
150  * Return a list of I2C tuner addresses to probe. Use only if the tuner
151  * addresses are unknown.
152  */
153 const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
154 {
155 	static const unsigned short radio_addrs[] = {
156 #if IS_ENABLED(CONFIG_MEDIA_TUNER_TEA5761)
157 		0x10,
158 #endif
159 		0x60,
160 		I2C_CLIENT_END
161 	};
162 	static const unsigned short demod_addrs[] = {
163 		0x42, 0x43, 0x4a, 0x4b,
164 		I2C_CLIENT_END
165 	};
166 	static const unsigned short tv_addrs[] = {
167 		0x42, 0x43, 0x4a, 0x4b,		/* tda8290 */
168 		0x60, 0x61, 0x62, 0x63, 0x64,
169 		I2C_CLIENT_END
170 	};
171 
172 	switch (type) {
173 	case ADDRS_RADIO:
174 		return radio_addrs;
175 	case ADDRS_DEMOD:
176 		return demod_addrs;
177 	case ADDRS_TV:
178 		return tv_addrs;
179 	case ADDRS_TV_WITH_DEMOD:
180 		return tv_addrs + 4;
181 	}
182 	return NULL;
183 }
184 EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);
185