i2c-dev: Unbound new-style i2c clients aren't busy
Let i2c-dev deal properly with new-style i2c clients. Instead of
considering them always busy, it needs to check wether a driver is
bound to them or not.
This is still not completely correct, as the client could become
busy later, but the same problem already existed before new-style
clients were introduced. We'll want to fix it someday.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 7360f9c..c21ae20 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -182,6 +182,29 @@
return ret;
}
+/* This address checking function differs from the one in i2c-core
+ in that it considers an address with a registered device, but no
+ bounded driver, as NOT busy. */
+static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
+{
+ struct list_head *item;
+ struct i2c_client *client;
+ int res = 0;
+
+ mutex_lock(&adapter->clist_lock);
+ list_for_each(item, &adapter->clients) {
+ client = list_entry(item, struct i2c_client, list);
+ if (client->addr == addr) {
+ if (client->driver)
+ res = -EBUSY;
+ break;
+ }
+ }
+ mutex_unlock(&adapter->clist_lock);
+
+ return res;
+}
+
static int i2cdev_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
@@ -213,8 +236,9 @@
if ((arg > 0x3ff) ||
(((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
return -EINVAL;
- if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
+ if (cmd == I2C_SLAVE && i2cdev_check_addr(client->adapter, arg))
return -EBUSY;
+ /* REVISIT: address could become busy later */
client->addr = arg;
return 0;
case I2C_TENBIT: