[PATCH v2] Input: elan_i2c - check if device is there before really probing

[Dmitry Torokhov]

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.

Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
---

v2: switched over to i2c_smbus_read_byte() as Guenter suggested

 drivers/input/mouse/elan_i2c_core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/input/mouse/elan_i2c_core.c 
b/drivers/input/mouse/elan_i2c_core.c
index 5d3b53dd2fa2..3b616cb7c67f 100644
--- a/drivers/input/mouse/elan_i2c_core.c
+++ b/drivers/input/mouse/elan_i2c_core.c
@@ -1091,6 +1091,13 @@ 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)
-- 
2.13.0.rc2.291.g57267f2277-goog


-- 
Dmitry