v4l2-i2c.c

  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 <linux/property.h>
  9#include <media/v4l2-common.h>
 10#include <media/v4l2-device.h>
 11
 12void v4l2_i2c_subdev_unregister(struct v4l2_subdev *sd)
 13{
 14	struct i2c_client *client = v4l2_get_subdevdata(sd);
 15
 16	/*
 17	 * We need to unregister the i2c client
 18	 * explicitly. We cannot rely on
 19	 * i2c_del_adapter to always unregister
 20	 * clients for us, since if the i2c bus is a
 21	 * platform bus, then it is never deleted.
 22	 *
 23	 * Device tree or ACPI based devices must not
 24	 * be unregistered as they have not been
 25	 * registered by us, and would not be
 26	 * re-created by just probing the V4L2 driver.
 27	 */
 28	if (client && !dev_fwnode(&client->dev))
 29		i2c_unregister_device(client);
 30}
 31
 32void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd,
 33			      struct i2c_client *client,
 34			      const char *devname, const char *postfix)
 35{
 36	if (!devname)
 37		devname = client->dev.driver->name;
 38	if (!postfix)
 39		postfix = "";
 40
 41	snprintf(sd->name, sizeof(sd->name), "%s%s %d-%04x", devname, postfix,
 42		 i2c_adapter_id(client->adapter), client->addr);
 43}
 44EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_set_name);
 45
 46void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
 47			  const struct v4l2_subdev_ops *ops)
 48{
 49	v4l2_subdev_init(sd, ops);
 50	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
 51	/* the owner is the same as the i2c_client's driver owner */
 52	sd->owner = client->dev.driver->owner;
 53	sd->dev = &client->dev;
 54	/* i2c_client and v4l2_subdev point to one another */
 55	v4l2_set_subdevdata(sd, client);
 56	i2c_set_clientdata(client, sd);
 57	v4l2_i2c_subdev_set_name(sd, client, NULL, NULL);
 58}
 59EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
 60
 61/* Load an i2c sub-device. */
 62struct v4l2_subdev
 63*v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
 64			   struct i2c_adapter *adapter,
 65			   struct i2c_board_info *info,
 66			   const unsigned short *probe_addrs)
 67{
 68	struct v4l2_subdev *sd = NULL;
 69	struct i2c_client *client;
 70
 71	if (!v4l2_dev)
 72		return NULL;
 73
 74	request_module(I2C_MODULE_PREFIX "%s", info->type);
 75
 76	/* Create the i2c client */
 77	if (info->addr == 0 && probe_addrs)
 78		client = i2c_new_scanned_device(adapter, info, probe_addrs,
 79						NULL);
 80	else
 81		client = i2c_new_client_device(adapter, info);
 82
 83	/*
 84	 * Note: by loading the module first we are certain that c->driver
 85	 * will be set if the driver was found. If the module was not loaded
 86	 * first, then the i2c core tries to delay-load the module for us,
 87	 * and then c->driver is still NULL until the module is finally
 88	 * loaded. This delay-load mechanism doesn't work if other drivers
 89	 * want to use the i2c device, so explicitly loading the module
 90	 * is the best alternative.
 91	 */
 92	if (!i2c_client_has_driver(client))
 93		goto error;
 94
 95	/* Lock the module so we can safely get the v4l2_subdev pointer */
 96	if (!try_module_get(client->dev.driver->owner))
 97		goto error;
 98	sd = i2c_get_clientdata(client);
 99
100	/*
101	 * Register with the v4l2_device which increases the module's
102	 * use count as well.
103	 */
104	if (__v4l2_device_register_subdev(v4l2_dev, sd, sd->owner))
105		sd = NULL;
106	/* Decrease the module use count to match the first try_module_get. */
107	module_put(client->dev.driver->owner);
108
109error:
110	/*
111	 * If we have a client but no subdev, then something went wrong and
112	 * we must unregister the client.
113	 */
114	if (!IS_ERR(client) && !sd)
115		i2c_unregister_device(client);
116	return sd;
117}
118EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);
119
120struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
121					struct i2c_adapter *adapter,
122					const char *client_type,
123					u8 addr,
124					const unsigned short *probe_addrs)
125{
126	struct i2c_board_info info;
127
128	/*
129	 * Setup the i2c board info with the device type and
130	 * the device address.
131	 */
132	memset(&info, 0, sizeof(info));
133	strscpy(info.type, client_type, sizeof(info.type));
134	info.addr = addr;
135
136	return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info,
137					 probe_addrs);
138}
139EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);
140
141/* Return i2c client address of v4l2_subdev. */
142unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
143{
144	struct i2c_client *client = v4l2_get_subdevdata(sd);
145
146	return client ? client->addr : I2C_CLIENT_END;
147}
148EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);
149
150/*
151 * Return a list of I2C tuner addresses to probe. Use only if the tuner
152 * addresses are unknown.
153 */
154const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
155{
156	static const unsigned short radio_addrs[] = {
157#if IS_ENABLED(CONFIG_MEDIA_TUNER_TEA5761)
158		0x10,
159#endif
160		0x60,
161		I2C_CLIENT_END
162	};
163	static const unsigned short demod_addrs[] = {
164		0x42, 0x43, 0x4a, 0x4b,
165		I2C_CLIENT_END
166	};
167	static const unsigned short tv_addrs[] = {
168		0x42, 0x43, 0x4a, 0x4b,		/* tda8290 */
169		0x60, 0x61, 0x62, 0x63, 0x64,
170		I2C_CLIENT_END
171	};
172
173	switch (type) {
174	case ADDRS_RADIO:
175		return radio_addrs;
176	case ADDRS_DEMOD:
177		return demod_addrs;
178	case ADDRS_TV:
179		return tv_addrs;
180	case ADDRS_TV_WITH_DEMOD:
181		return tv_addrs + 4;
182	}
183	return NULL;
184}
185EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);