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i2c: Replace list-based mechanism for handling auto-detected clients

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So far a list is used to track auto-detected clients per driver.
The same functionality can be achieved much simpler by flagging
auto-detected clients.

Two notes regarding the usage of driver_for_each_device:
In our case it can't fail, however the function is annotated __must_check.
So a little workaround is needed to avoid a compiler warning.
Then we may remove nodes from the list over which we iterate.
This is safe, see the explanation at the beginning of lib/klist.c.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
[wsa: fixed description of the new flag]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This commit is contained in:
Heiner Kallweit 2024-11-01 23:09:51 +01:00 committed by Wolfram Sang
parent 60be800603
commit 56a50667cb
2 changed files with 17 additions and 38 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

52
drivers/i2c/i2c-core-base.c
View file

@ -1696,23 +1696,6 @@ int i2c_add_numbered_adapter(struct i2c_adapter *adap)
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
static void i2c_do_del_adapter(struct i2c_driver *driver,
struct i2c_adapter *adapter)
{
struct i2c_client *client, *_n;
/* Remove the devices we created ourselves as the result of hardware
* probing (using a driver's detect method) */
list_for_each_entry_safe(client, _n, &driver->clients, detected) {
if (client->adapter == adapter) {
dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
client->name, client->addr);
list_del(&client->detected);
i2c_unregister_device(client);
}
}
}
static int __unregister_client(struct device *dev, void *dummy)
{
struct i2c_client *client = i2c_verify_client(dev);
@ -1728,12 +1711,6 @@ static int __unregister_dummy(struct device *dev, void *dummy)
return 0;
}
static int __process_removed_adapter(struct device_driver *d, void *data)
{
i2c_do_del_adapter(to_i2c_driver(d), data);
return 0;
}
/**
* i2c_del_adapter - unregister I2C adapter
* @adap: the adapter being unregistered
@ -1757,11 +1734,6 @@ void i2c_del_adapter(struct i2c_adapter *adap)
}
i2c_acpi_remove_space_handler(adap);
/* Tell drivers about this removal */
mutex_lock(&core_lock);
bus_for_each_drv(&i2c_bus_type, NULL, adap,
__process_removed_adapter);
mutex_unlock(&core_lock);
/* Remove devices instantiated from sysfs */
mutex_lock_nested(&adap->userspace_clients_lock,
@ -1780,8 +1752,10 @@ void i2c_del_adapter(struct i2c_adapter *adap)
* we can't remove the dummy devices during the first pass: they
* could have been instantiated by real devices wishing to clean
* them up properly, so we give them a chance to do that first. */
mutex_lock(&core_lock);
device_for_each_child(&adap->dev, NULL, __unregister_client);
device_for_each_child(&adap->dev, NULL, __unregister_dummy);
mutex_unlock(&core_lock);
/* device name is gone after device_unregister */
dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
@ -2001,7 +1975,6 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
/* add the driver to the list of i2c drivers in the driver core */
driver->driver.owner = owner;
driver->driver.bus = &i2c_bus_type;
INIT_LIST_HEAD(&driver->clients);
/* When registration returns, the driver core
* will have called probe() for all matching-but-unbound devices.
@ -2019,10 +1992,13 @@ int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
}
EXPORT_SYMBOL(i2c_register_driver);
static int __process_removed_driver(struct device *dev, void *data)
static int __i2c_unregister_detected_client(struct device *dev, void *argp)
{
if (dev->type == &i2c_adapter_type)
i2c_do_del_adapter(data, to_i2c_adapter(dev));
struct i2c_client *client = i2c_verify_client(dev);
if (client && client->flags & I2C_CLIENT_AUTO)
i2c_unregister_device(client);
return 0;
}
@ -2033,7 +2009,12 @@ static int __process_removed_driver(struct device *dev, void *data)
*/
void i2c_del_driver(struct i2c_driver *driver)
{
i2c_for_each_dev(driver, __process_removed_driver);
mutex_lock(&core_lock);
/* Satisfy __must_check, function can't fail */
if (driver_for_each_device(&driver->driver, NULL, NULL,
__i2c_unregister_detected_client)) {
}
mutex_unlock(&core_lock);
driver_unregister(&driver->driver);
pr_debug("driver [%s] unregistered\n", driver->driver.name);
@ -2460,6 +2441,7 @@ static int i2c_detect_address(struct i2c_client *temp_client,
/* Finally call the custom detection function */
memset(&info, 0, sizeof(struct i2c_board_info));
info.addr = addr;
info.flags = I2C_CLIENT_AUTO;
err = driver->detect(temp_client, &info);
if (err) {
/* -ENODEV is returned if the detection fails. We catch it
@ -2486,9 +2468,7 @@ static int i2c_detect_address(struct i2c_client *temp_client,
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
info.type, info.addr);
client = i2c_new_client_device(adapter, &info);
if (!IS_ERR(client))
list_add_tail(&client->detected, &driver->clients);
else
if (IS_ERR(client))
dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
info.type, info.addr);
}

3
include/linux/i2c.h
View file

@ -244,7 +244,6 @@ enum i2c_driver_flags {
* @id_table: List of I2C devices supported by this driver
* @detect: Callback for device detection
* @address_list: The I2C addresses to probe (for detect)
* @clients: List of detected clients we created (for i2c-core use only)
* @flags: A bitmask of flags defined in &enum i2c_driver_flags
*
* The driver.owner field should be set to the module owner of this driver.
@ -299,7 +298,6 @@ struct i2c_driver {
/* Device detection callback for automatic device creation */
int (*detect)(struct i2c_client *client, struct i2c_board_info *info);
const unsigned short *address_list;
struct list_head clients;
u32 flags;
};
@ -334,6 +332,7 @@ struct i2c_client {
#define I2C_CLIENT_SLAVE 0x20 /* we are the slave */
#define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */
#define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */
#define I2C_CLIENT_AUTO 0x100 /* client was auto-detected */
#define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */
/* Must match I2C_M_STOP|IGNORE_NAK */