diff options
Diffstat (limited to 'drivers/i2c/i2c-dev.c')
| -rw-r--r-- | drivers/i2c/i2c-dev.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index 7360f9c37256..c21ae20ae362 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -182,6 +182,29 @@ static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t c 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 @@ static int i2cdev_ioctl(struct inode *inode, struct file *file, 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: |