Commit 56a50667 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Wolfram Sang
Browse files

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



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: default avatarHeiner Kallweit <hkallweit1@gmail.com>
[wsa: fixed description of the new flag]
Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
parent 60be8006

drivers/i2c/i2c-core-base.c

+16 −36
Original line number Diff line number Diff line
@@ -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);

	}

include/linux/i2c.h

+1 −2
Original line number Diff line number Diff line
@@ -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 */