i2c bus 路径
struct bus_type i2c_bus_type = {
.name = "i2c",
.match = i2c_device_match,
.probe = i2c_device_probe,
.remove = i2c_device_remove,
.shutdown = i2c_device_shutdown,
};
EXPORT_SYMBOL_GPL(i2c_bus_type);
static int __init i2c_init(void)
{
int retval;
retval = of_alias_get_highest_id("i2c");
down_write(&__i2c_board_lock);
if (retval >= __i2c_first_dynamic_bus_num)
__i2c_first_dynamic_bus_num = retval + 1;
up_write(&__i2c_board_lock);
retval = bus_register(&i2c_bus_type);
if (retval)
return retval;
is_registered = true;
#ifdef CONFIG_I2C_COMPAT
i2c_adapter_compat_class = class_compat_register("i2c-adapter");
if (!i2c_adapter_compat_class) {
retval = -ENOMEM;
goto bus_err;
}
#endif
retval = i2c_add_driver(&dummy_driver);
if (retval)
goto class_err;
if (IS_ENABLED(CONFIG_OF_DYNAMIC))
WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
if (IS_ENABLED(CONFIG_ACPI))
WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
return 0;
class_err:
#ifdef CONFIG_I2C_COMPAT
class_compat_unregister(i2c_adapter_compat_class);
bus_err:
#endif
is_registered = false;
bus_unregister(&i2c_bus_type);
return retval;
}
结合 .name = “i2c”, retval = bus_register(&i2c_bus_type);
这表明命名是 “i2c”，通过bus_register注册到bus 总线目录下。
实际如下图
i2c adaptor 路径
static int i2c_register_adapter(struc
t i2c_adapter *adap)
{
int res = -EINVAL;
/* Can't register until after driver model init */
if (WARN_ON(!is_registered)) {
res = -EAGAIN;
goto out_list;
}
/* Sanity checks */
if (WARN(!adap->name[0], "i2c adapter has no name"))
goto out_list;
if (!adap->algo) {
pr_err("adapter '%s': no algo supplied!\n", adap->name);
goto out_list;
}
if (!adap->lock_ops)
adap->lock_ops = &i2c_adapter_lock_ops;
adap->locked_flags = 0;
rt_mutex_init(&adap->bus_lock);
rt_mutex_init(&adap->mux_lock);
mutex_init(&adap->userspace_clients_lock);
INIT_LIST_HEAD(&adap->userspace_clients);
/* Set default timeout to 1 second if not already set */
if (adap->timeout == 0)
adap->timeout = HZ;
/* register soft irqs for Host Notify */
res = i2c_setup_host_notify_irq_domain(adap);
if (res) {
pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
adap->name, res);
goto out_list;
}
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.bus = &i2c_bus_type;
adap->dev.type = &i2c_adapter_type;
res = device_register(&adap->dev);
if (res) {
pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
goto out_list;
}
res = i2c_setup_smbus_alert(adap);
if (res)
goto out_reg;
device_enable_async_suspend(&adap->dev);
pm_runtime_no_callbacks(&adap->dev);
pm_suspend_ignore_children(&adap->dev, true);
pm_runtime_enable(&adap->dev);
res = i2c_init_recovery(adap);
if (res == -EPROBE_DEFER)
goto out_reg;
dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
#ifdef CONFIG_I2C_COMPAT
res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
adap->dev.parent);
if (res)
dev_warn(&adap->dev,
"Failed to create compatibility class link\n");
#endif
/* create pre-declared device nodes */
of_i2c_register_devices(adap);
i2c_acpi_install_space_handler(adap);
i2c_acpi_register_devices(adap);
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
/* Notify drivers */
mutex_lock(&core_lock);
bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
mutex_unlock(&core_lock);
return 0;
out_reg:
init_completion(&adap->dev_released);
device_unregister(&adap->dev);
wait_for_completion(&adap->dev_released);
out_list:
mutex_lock(&core_lock);
idr_remove(&i2c_adapter_idr, adap->nr);
mutex_unlock(&core_lock);
return res;
}
通过这2行
dev_set_name(&adap->dev, “i2c-%d”, adap->nr);
adap->dev.bus = &i2c_bus_type;
表明适配器的路径在bus 路径的devices下面。命名风格是"i2c-%d"，%d是注册的适配器的总线号。实际如下图
i2c client路径
struct i2c_client *
i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
{
struct i2c_client *client;
int status;
client = kzalloc(sizeof *client, GFP_KERNEL);
if (!client)
return ERR_PTR(-ENOMEM);
client->adapter = adap;
client->dev.platform_data = info->platform_data;
client->flags = info->flags;
client->addr = info->addr;
client->init_irq = info->irq;
if (!client->init_irq)
client->init_irq = i2c_dev_irq_from_resources(info->resources,
info->num_resources);
strscpy(client->name, info->type, sizeof(client->name));
status = i2c_check_addr_validity(client->addr, client->flags);
if (status) {
dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
goto out_err_silent;
}
/* Check for address business */
status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
if (status)
goto out_err;
client->dev.parent = &client->adapter->dev;
client->dev.bus = &i2c_bus_type;
client->dev.type = &i2c_client_type;
client->dev.of_node = of_node_get(info->of_node);
client->dev.fwnode = info->fwnode;
device_enable_async_suspend(&client->dev);
i2c_dev_set_name(adap, client, info);
if (info->swnode) {
status = device_add_software_node(&client->dev, info->swnode);
if (status) {
dev_err(&adap->dev,
"Failed to add software node to client %s: %d\n",
client->name, status);
goto out_err_put_of_node;
}
}
status = device_register(&client->dev);
if (status)
goto out_remove_swnode;
dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
client->name, dev_name(&client->dev));
return client;
out_remove_swnode:
device_remove_software_node(&client->dev);
out_err_put_of_node:
of_node_put(info->of_node);
out_err:
dev_err(&adap->dev,
"Failed to register i2c client %s at 0x%02x (%d)\n",
client->name, client->addr, status);
out_err_silent:
kfree(client);
return ERR_PTR(status);
}
EXPORT_SYMBOL_GPL(i2c_new_client_device);
client->dev.parent = &client->adapter->dev; 表明client 实体对应的device节点在adapter的目录下，命名由 strscpy(client->name, info->type, sizeof(client->name)); 和 i2c_dev_set_name(adap, client, info)这两项决定。
i2c_dev_set_name 的实现如下
static void i2c_dev_set_name(struct i2c_adapter *adap,
struct i2c_client *client,
struct i2c_board_info const *info)
{
struct acpi_device *adev = ACPI_COMPANION(&client->dev);
if (info && info->dev_name) {
dev_set_name(&client->dev, "i2c-%s", info->dev_name);
return;
}
if (adev) {
dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
return;
}
dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
i2c_encode_flags_to_addr(client));
}
static inline int i2c_adapter_id(struct i2c_adapter *adap)
{
return adap->nr;
}
static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
{
unsigned short addr = client->addr;
/* For some client flags, add an arbitrary offset to avoid collisions */
if (client->flags & I2C_CLIENT_TEN)
addr |= I2C_ADDR_OFFSET_TEN_BIT;
if (client->flags & I2C_CLIENT_SLAVE)
addr |= I2C_ADDR_OFFSET_SLAVE;
return addr;
}
#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
#define I2C_ADDR_OFFSET_SLAVE 0x1000
实例如下图
上图第一个红框是常规命名方式，下面的是ACPI的命名方式
