mfd: 88pm860x: Fix possible NULL pointer dereference on i2c_new_dummy error

commit 159ce52a6b777fc82fa0b51c7440e25f9e4c6feb upstream.

During probe the driver allocates dummy I2C device for companion chip
with i2c_new_dummy() but it does not check the return value of this call.

In case of error (i2c_new_device(): memory allocation failure or I2C
address cannot be used) this function returns NULL which is later used
by regmap_init_i2c().

If i2c_new_dummy() fails for companion device, fail also the probe for
main MFD driver.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/mfd/88pm860x-core.c b/drivers/mfd/88pm860x-core.c
index 31ca55548ef9..c270d0b268ad 100644
--- a/drivers/mfd/88pm860x-core.c
+++ b/drivers/mfd/88pm860x-core.c
@@ -1179,6 +1179,11 @@ static int pm860x_probe(struct i2c_client *client,
                 chip->companion_addr = pdata->companion_addr;
                 chip->companion = i2c_new_dummy(chip->client->adapter,
                                                 chip->companion_addr);
+                if (!chip->companion) {
+                        dev_err(&client->dev,
+                                "Failed to allocate I2C companion device\n");
+                        return -ENODEV;
+                }
                 chip->regmap_companion = regmap_init_i2c(chip->companion,
                                                         &pm860x_regmap_config);
                 if (IS_ERR(chip->regmap_companion)) {