// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * v4l2-i2c - I2C helpers for Video4Linux2
 */

#include <linux/i2c.h>
#include <linux/module.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>

void v4l2_i2c_subdev_unregister(struct v4l2_subdev *sd)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        /*
         * We need to unregister the i2c client
         * explicitly. We cannot rely on
         * i2c_del_adapter to always unregister
         * clients for us, since if the i2c bus is a
         * platform bus, then it is never deleted.
         *
         * Device tree or ACPI based devices must not
         * be unregistered as they have not been
         * registered by us, and would not be
         * re-created by just probing the V4L2 driver.
         */
        if (client && !client->dev.of_node && !client->dev.fwnode)
                i2c_unregister_device(client);
}

void v4l2_i2c_subdev_set_name(struct v4l2_subdev *sd,
                              struct i2c_client *client,
                              const char *devname, const char *postfix)
{
        if (!devname)
                devname = client->dev.driver->name;
        if (!postfix)
                postfix = "";

        snprintf(sd->name, sizeof(sd->name), "%s%s %d-%04x", devname, postfix,
                 i2c_adapter_id(client->adapter), client->addr);
}
EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_set_name);

void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
                          const struct v4l2_subdev_ops *ops)
{
        v4l2_subdev_init(sd, ops);
        sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
        /* the owner is the same as the i2c_client's driver owner */
        sd->owner = client->dev.driver->owner;
        sd->dev = &client->dev;
        /* i2c_client and v4l2_subdev point to one another */
        v4l2_set_subdevdata(sd, client);
        i2c_set_clientdata(client, sd);
        v4l2_i2c_subdev_set_name(sd, client, NULL, NULL);
}
EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);

/* Load an i2c sub-device. */
struct v4l2_subdev
*v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
                           struct i2c_adapter *adapter,
                           struct i2c_board_info *info,
                           const unsigned short *probe_addrs)
{
        struct v4l2_subdev *sd = NULL;
        struct i2c_client *client;

        if (!v4l2_dev)
                return NULL;

        request_module(I2C_MODULE_PREFIX "%s", info->type);

        /* Create the i2c client */
        if (info->addr == 0 && probe_addrs)
                client = i2c_new_scanned_device(adapter, info, probe_addrs,
                                                NULL);
        else
                client = i2c_new_client_device(adapter, info);

        /*
         * Note: by loading the module first we are certain that c->driver
         * will be set if the driver was found. If the module was not loaded
         * first, then the i2c core tries to delay-load the module for us,
         * and then c->driver is still NULL until the module is finally
         * loaded. This delay-load mechanism doesn't work if other drivers
         * want to use the i2c device, so explicitly loading the module
         * is the best alternative.
         */
        if (!i2c_client_has_driver(client))
                goto error;

        /* Lock the module so we can safely get the v4l2_subdev pointer */
        if (!try_module_get(client->dev.driver->owner))
                goto error;
        sd = i2c_get_clientdata(client);

        /*
         * Register with the v4l2_device which increases the module's
         * use count as well.
         */
        if (v4l2_device_register_subdev(v4l2_dev, sd))
                sd = NULL;
        /* Decrease the module use count to match the first try_module_get. */
        module_put(client->dev.driver->owner);

error:
        /*
         * If we have a client but no subdev, then something went wrong and
         * we must unregister the client.
         */
        if (!IS_ERR(client) && !sd)
                i2c_unregister_device(client);
        return sd;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);

struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
                                        struct i2c_adapter *adapter,
                                        const char *client_type,
                                        u8 addr,
                                        const unsigned short *probe_addrs)
{
        struct i2c_board_info info;

        /*
         * Setup the i2c board info with the device type and
         * the device address.
         */
        memset(&info, 0, sizeof(info));
        strscpy(info.type, client_type, sizeof(info.type));
        info.addr = addr;

        return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info,
                                         probe_addrs);
}
EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);

/* Return i2c client address of v4l2_subdev. */
unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        return client ? client->addr : I2C_CLIENT_END;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);

/*
 * Return a list of I2C tuner addresses to probe. Use only if the tuner
 * addresses are unknown.
 */
const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
{
        static const unsigned short radio_addrs[] = {
#if IS_ENABLED(CONFIG_MEDIA_TUNER_TEA5761)
                0x10,
#endif
                0x60,
                I2C_CLIENT_END
        };
        static const unsigned short demod_addrs[] = {
                0x42, 0x43, 0x4a, 0x4b,
                I2C_CLIENT_END
        };
        static const unsigned short tv_addrs[] = {
                0x42, 0x43, 0x4a, 0x4b,         /* tda8290 */
                0x60, 0x61, 0x62, 0x63, 0x64,
                I2C_CLIENT_END
        };

        switch (type) {
        case ADDRS_RADIO:
                return radio_addrs;
        case ADDRS_DEMOD:
                return demod_addrs;
        case ADDRS_TV:
                return tv_addrs;
        case ADDRS_TV_WITH_DEMOD:
                return tv_addrs + 4;
        }
        return NULL;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);