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Commit 9ea3e941 authored by Jean Delvare's avatar Jean Delvare Committed by Jean Delvare
Browse files

i2c-dev: Use standard bus notification mechanism 



Use the standard driver core mechanism to keep track of i2c adapters
present on the system: i2c_for_each_dev and a notifier. This will let
us deprecate and ultimately remove the legacy attach_adapter and
detach_adapter callbacks in i2c_driver.

Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 7ae31482

drivers/i2c/i2c-dev.c

+39 −21
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 


#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/notifier.h>

#include <linux/fs.h>

#include <linux/slab.h>

#include <linux/init.h>
@@ -37,16 +39,13 @@ 
#include <linux/jiffies.h>

#include <linux/uaccess.h>



static struct i2c_driver i2cdev_driver;



/*

 * An i2c_dev represents an i2c_adapter ... an I2C or SMBus master, not a

 * slave (i2c_client) with which messages will be exchanged.  It's coupled

 * with a character special file which is accessed by user mode drivers.

 *

 * The list of i2c_dev structures is parallel to the i2c_adapter lists

 * maintained by the driver model, and is updated using notifications

 * delivered to the i2cdev_driver.

 * maintained by the driver model, and is updated using bus notifications.

 */

struct i2c_dev {

	struct list_head list;
@@ -491,7 +490,6 @@ static int i2cdev_open(struct inode *inode, struct file *file) 
		return -ENOMEM;

	}

	snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);

	client->driver = &i2cdev_driver;



	client->adapter = adap;

	file->private_data = client;
@@ -522,19 +520,18 @@ static const struct file_operations i2cdev_fops = { 


/* ------------------------------------------------------------------------- */



/*

 * The legacy "i2cdev_driver" is used primarily to get notifications when

 * I2C adapters are added or removed, so that each one gets an i2c_dev

 * and is thus made available to userspace driver code.

 */



static struct class *i2c_dev_class;



static int i2cdev_attach_adapter(struct i2c_adapter *adap)

static int i2cdev_attach_adapter(struct device *dev, void *dummy)

{

	struct i2c_adapter *adap;

	struct i2c_dev *i2c_dev;

	int res;



	if (dev->type != &i2c_adapter_type)

		return 0;

	adap = to_i2c_adapter(dev);



	i2c_dev = get_free_i2c_dev(adap);

	if (IS_ERR(i2c_dev))

		return PTR_ERR(i2c_dev);
@@ -561,10 +558,15 @@ static int i2cdev_attach_adapter(struct i2c_adapter *adap) 
	return res;

}



static int i2cdev_detach_adapter(struct i2c_adapter *adap)

static int i2cdev_detach_adapter(struct device *dev, void *dummy)

{

	struct i2c_adapter *adap;

	struct i2c_dev *i2c_dev;



	if (dev->type != &i2c_adapter_type)

		return 0;

	adap = to_i2c_adapter(dev);



	i2c_dev = i2c_dev_get_by_minor(adap->nr);

	if (!i2c_dev) /* attach_adapter must have failed */

		return 0;
@@ -577,12 +579,23 @@ static int i2cdev_detach_adapter(struct i2c_adapter *adap) 
	return 0;

}



static struct i2c_driver i2cdev_driver = {

	.driver = {

		.name	= "dev_driver",

	},

	.attach_adapter	= i2cdev_attach_adapter,

	.detach_adapter	= i2cdev_detach_adapter,

int i2cdev_notifier_call(struct notifier_block *nb, unsigned long action,

			 void *data)

{

	struct device *dev = data;



	switch (action) {

	case BUS_NOTIFY_ADD_DEVICE:

		return i2cdev_attach_adapter(dev, NULL);

	case BUS_NOTIFY_DEL_DEVICE:

		return i2cdev_detach_adapter(dev, NULL);

	}



	return 0;

}



static struct notifier_block i2cdev_notifier = {

	.notifier_call = i2cdev_notifier_call,

};



/* ------------------------------------------------------------------------- */
@@ -607,10 +620,14 @@ static int __init i2c_dev_init(void) 
		goto out_unreg_chrdev;

	}



	res = i2c_add_driver(&i2cdev_driver);

	/* Keep track of adapters which will be added or removed later */

	res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);

	if (res)

		goto out_unreg_class;



	/* Bind to already existing adapters right away */

	i2c_for_each_dev(NULL, i2cdev_attach_adapter);



	return 0;



out_unreg_class:
@@ -624,7 +641,8 @@ static int __init i2c_dev_init(void) 


static void __exit i2c_dev_exit(void)

{

	i2c_del_driver(&i2cdev_driver);

	bus_unregister_notifier(&i2c_bus_type, &i2cdev_notifier);

	i2c_for_each_dev(NULL, i2cdev_detach_adapter);

	class_destroy(i2c_dev_class);

	unregister_chrdev(I2C_MAJOR, "i2c");

}