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// 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 "i2c-core.h"
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{
int ret;
if (!client || !slave_cb) {
WARN(1, "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 (!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);
/**
* 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)
{
if (IS_BUILTIN(CONFIG_OF) && dev->of_node) {
struct device_node *child;
u32 reg;
for_each_child_of_node(dev->of_node, child) {
of_property_read_u32(child, "reg", ®);
if (reg & I2C_OWN_SLAVE_ADDRESS) {
of_node_put(child);
return true;
}
}
} else if (IS_BUILTIN(CONFIG_ACPI) && ACPI_HANDLE(dev)) {
dev_dbg(dev, "ACPI slave is not supported yet\n");
}
return false;
}
EXPORT_SYMBOL_GPL(i2c_detect_slave_mode);
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