drivers/i2c/i2c-core-slave.c

Source file repositories/reference/linux-study-clean/drivers/i2c/i2c-core-slave.c

File Facts

System
Linux kernel
Corpus path
drivers/i2c/i2c-core-slave.c
Extension
.c
Size
3271 bytes
Lines
128
Domain
Driver Families
Bucket
drivers/i2c
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

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_call__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");
	}

Annotation

Implementation Notes