i2c: Fix oops on bus multiplexer driver loading

The two I2C bus multiplexer drivers (i2c-amd756-s4882 and
i2c-nforce2-s4985) make use of the bus they want to multiplex before
checking if it is really present. Swap the instructions to test for
presence first. This fixes a oops reported by Ingo Molnar.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/i2c/busses/i2c-amd756-s4882.c b/drivers/i2c/busses/i2c-amd756-s4882.c
index 72872d1e63ef..8ba2bcf727d3 100644
--- a/drivers/i2c/busses/i2c-amd756-s4882.c
+++ b/drivers/i2c/busses/i2c-amd756-s4882.c
@@ -155,6 +155,9 @@ static int __init amd756_s4882_init(void)
         int i, error;
         union i2c_smbus_data ioconfig;
 
+        if (!amd756_smbus.dev.parent)
+                return -ENODEV;
+
         /* Configure the PCA9556 multiplexer */
         ioconfig.byte = 0x00; /* All I/O to output mode */
         error = i2c_smbus_xfer(&amd756_smbus, 0x18, 0, I2C_SMBUS_WRITE, 0x03,
@@ -168,11 +171,7 @@ static int __init amd756_s4882_init(void)
         /* Unregister physical bus */
         error = i2c_del_adapter(&amd756_smbus);
         if (error) {
-                if (error == -EINVAL)
-                        error = -ENODEV;
-                else
-                        dev_err(&amd756_smbus.dev, "Physical bus removal "
-                                "failed\n");
+                dev_err(&amd756_smbus.dev, "Physical bus removal failed\n");
                 goto ERROR0;
         }