mfd: twl6040: Check for error when reading revision register

We may have an error when reading the revision register, so check for
the returned value.

Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
index f15114f8c258..6e88f25832fb 100644
--- a/drivers/mfd/twl6040.c
+++ b/drivers/mfd/twl6040.c
@@ -661,6 +661,11 @@ static int twl6040_probe(struct i2c_client *client,
         init_completion(&twl6040->ready);
 
         twl6040->rev = twl6040_reg_read(twl6040, TWL6040_REG_ASICREV);
+        if (twl6040->rev < 0) {
+                dev_err(&client->dev, "Failed to read revision register: %d\n",
+                        twl6040->rev);
+                goto gpio_err;
+        }
 
         /* ERRATA: Automatic power-up is not possible in ES1.0 */
         if (twl6040_get_revid(twl6040) > TWL6040_REV_ES1_0)