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
 11void 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
 31void 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}
 43EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_set_name);
 44
 45void 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}
 58EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
 59
 60/* Load an i2c sub-device. */
 61struct 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
108error:
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}
117EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);
118
119struct 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}
138EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);
139
140/* Return i2c client address of v4l2_subdev. */
141unsigned 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}
147EXPORT_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 */
153const 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}
184EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);