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

[ Upstream commit c5928551fd41b2eecdad78fa2be2a4a13ed5fde9 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/mouse/elan_i2c_core.c b/drivers/input/mouse/elan_i2c_core.c
index c9d491b..3851d57 100644 (file)
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -1082,6 +1082,13 @@ 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)