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i2c-dev: Use standard bus notification mechanism

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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: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Jean Delvare 2011-03-20 14:50:52 +01:00 committed by Jean Delvare
parent 7ae31482a8
commit 9ea3e941d1
1 changed files with 39 additions and 21 deletions
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60
drivers/i2c/i2c-dev.c
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@ -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 @@ error:
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 @@ out:
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");
}