// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linux I2C core slave support code
 *
 * Copyright (C) 2014 by Wolfram Sang <wsa@sang-engineering.com>
 */

#include <dt-bindings/i2c/i2c.h>
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/of.h>
#include <linux/property.h>

#include "i2c-core.h"

#define CREATE_TRACE_POINTS
#include <trace/events/i2c_slave.h>

int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
        int ret;

        if (WARN(IS_ERR_OR_NULL(client) || !slave_cb, "insufficient data\n"))
                return -EINVAL;

        if (!(client->flags & I2C_CLIENT_SLAVE))
                dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
                         __func__);

        if (!(client->flags & I2C_CLIENT_TEN)) {
                /* Enforce stricter address checking */
                ret = i2c_check_7bit_addr_validity_strict(client->addr);
                if (ret) {
                        dev_err(&client->dev, "%s: invalid address\n", __func__);
                        return ret;
                }
        }

        if (!client->adapter->algo->reg_slave) {
                dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
                return -EOPNOTSUPP;
        }

        client->slave_cb = slave_cb;

        i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
        ret = client->adapter->algo->reg_slave(client);
        i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);

        if (ret) {
                client->slave_cb = NULL;
                dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
        }

        return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_register);

int i2c_slave_unregister(struct i2c_client *client)
{
        int ret;

        if (IS_ERR_OR_NULL(client))
                return -EINVAL;

        if (!client->adapter->algo->unreg_slave) {
                dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
                return -EOPNOTSUPP;
        }

        i2c_lock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);
        ret = client->adapter->algo->unreg_slave(client);
        i2c_unlock_bus(client->adapter, I2C_LOCK_ROOT_ADAPTER);

        if (ret == 0)
                client->slave_cb = NULL;
        else
                dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);

        return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);

int i2c_slave_event(struct i2c_client *client,
                    enum i2c_slave_event event, u8 *val)
{
        int ret = client->slave_cb(client, event, val);

        if (trace_i2c_slave_enabled())
                trace_i2c_slave(client, event, val, ret);

        return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_event);

/**
 * i2c_detect_slave_mode - detect operation mode
 * @dev: The device owning the bus
 *
 * This checks the device nodes for an I2C slave by checking the address
 * used in the reg property. If the address match the I2C_OWN_SLAVE_ADDRESS
 * flag this means the device is configured to act as a I2C slave and it will
 * be listening at that address.
 *
 * Returns true if an I2C own slave address is detected, otherwise returns
 * false.
 */
bool i2c_detect_slave_mode(struct device *dev)
{
        struct fwnode_handle *fwnode = dev_fwnode(dev);

        if (is_of_node(fwnode)) {
                u32 reg;

                fwnode_for_each_child_node_scoped(fwnode, child) {
                        fwnode_property_read_u32(child, "reg", &reg);
                        if (reg & I2C_OWN_SLAVE_ADDRESS)
                                return true;
                }
        } else if (is_acpi_device_node(fwnode)) {
                dev_dbg(dev, "ACPI slave is not supported yet\n");
        }
        return false;
}
EXPORT_SYMBOL_GPL(i2c_detect_slave_mode);