drivers/media/v4l2-core/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 <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);