[PATCH AUTOSEL for 4.4 024/167] Input: elan_i2c - check if device is there before really probing

Sasha Levin
2018-03-19T16:07:11Z

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

[ 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>
---
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 c9d491bc85e0..3851d5715772 100644
--- 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)
--
2.14.1