i2c: Check for address validity on client registration

Do basic address validity checks when a client is being registered. We
already had checks in place for devices which are being detected, but
not for devices which are simply instantiated.

This is a very basic check. We don't want to do strict checking here
because some devices are known to infringe the I2C address constraints
(e.g. IR receivers at 7-bit address 0x7a while this value is
supposedly reserved for 10-bit addresses.) So we assume the caller
knows what it is doing.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Matthieu Castet <castet.matthieu@free.fr>

1 files changed, 26 insertions, 7 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index f744f73e3ff5..96f01331544d 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -371,6 +371,22 @@ struct i2c_client *i2c_verify_client(struct device *dev)
 EXPORT_SYMBOL(i2c_verify_client);
 
 
+/* This is a permissive address validity check, I2C address map constraints
+ * are purposedly not enforced, except for the general call address. */
+static int i2c_check_client_addr_validity(const struct i2c_client *client)
+{
+        if (client->flags & I2C_CLIENT_TEN) {
+                /* 10-bit address, all values are valid */
+                if (client->addr > 0x3ff)
+                        return -EINVAL;
+        } else {
+                /* 7-bit address, reject the general call address */
+                if (client->addr == 0x00 || client->addr > 0x7f)
+                        return -EINVAL;
+        }
+        return 0;
+}
+
 /**
  * i2c_new_device - instantiate an i2c device
  * @adap: the adapter managing the device
@@ -410,6 +426,14 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 
         strlcpy(client->name, info->type, sizeof(client->name));
 
+        /* Check for address validity */
+        status = i2c_check_client_addr_validity(client);
+        if (status) {
+                dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
+                        client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
+                goto out_err_silent;
+        }
+
         /* Check for address business */
         status = i2c_check_addr(adap, client->addr);
         if (status)
@@ -436,6 +460,7 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 out_err:
         dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
                 "(%d)\n", client->name, client->addr, status);
+out_err_silent:
         kfree(client);
         return NULL;
 }
@@ -561,15 +586,9 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
                 return -EINVAL;
         }
 
-        if (info.addr < 0x03 || info.addr > 0x77) {
-                dev_err(dev, "%s: Invalid I2C address 0x%hx\n", "new_device",
-                        info.addr);
-                return -EINVAL;
-        }
-
         client = i2c_new_device(adap, &info);
         if (!client)
-                return -EEXIST;
+                return -EINVAL;
 
         /* Keep track of the added device */
         i2c_lock_adapter(adap);