Input: elan_i2c - check if device is there before really probing

Before trying to properly initialize the touchpad and generate bunch of
errors, let's first see it there is anything at the given address. If we
get error, fail silently with -ENXIO.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
index d5ab9dd..551ad29 100644 (file)
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -1077,6 +1077,13 @@ static int elan_probe(struct i2c_client *client,
                return error;
        }
 
+       /* Make sure there is something at this address */
+       error = i2c_smbus_read_byte(client);
+       if (error < 0) {
+               dev_dbg(&client->dev, "nothing at this address: %d\n", error);
+               return -ENXIO;
+       }
+
        /* Initialize the touchpad. */
        error = elan_initialize(data);
        if (error)