[PATCH 4.9 033/310] Input: elan_i2c - check if device is there before really probing

From: Greg Kroah-Hartman
Date: Wed Apr 11 2018 - 16:05:45 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>


[ 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@xxxxxxxxxxxx>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/input/mouse/elan_i2c_core.c | 7 +++++++
1 file changed, 7 insertions(+)

--- 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
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)