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From:   Takashi Iwai <tiwai@suse.de>
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc:     linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: [PATCH] Input: elants_i2c - Fix NULL dereference at probing
Date:   Wed, 26 May 2021 21:43:01 +0200
Message-Id: <20210526194301.28780-1-tiwai@suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The recent change in elants_i2c driver to support more chips
introduced a regression leading to Oops at probing.  The driver reads
id->driver_data, but the id may be NULL depending on the device type
the driver gets bound.

Add a NULL check and falls back to the default EKTH3500.

Fixes: 9517b95bdc46 ("Input: elants_i2c - add support for eKTF3624")
BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1186454
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/input/touchscreen/elants_i2c.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 17540bdb1eaf..172a6951cead 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -1396,7 +1396,10 @@ static int elants_i2c_probe(struct i2c_client *client,
 	init_completion(&ts->cmd_done);
 
 	ts->client = client;
-	ts->chip_id = (enum elants_chip_id)id->driver_data;
+	if (id)
+		ts->chip_id = (enum elants_chip_id)id->driver_data;
+	else
+		ts->chip_id = EKTH3500;
 	i2c_set_clientdata(client, ts);
 
 	ts->vcc33 = devm_regulator_get(&client->dev, "vcc33");
-- 
2.26.2