iio: hmc5843: fix potential NULL pointer dereferences

BugLink: https://bugs.launchpad.net/bugs/1832661

[ Upstream commit 536cc27d ]

devm_regmap_init_i2c may fail and return NULL. The fix returns
the error when it fails.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/staging/iio/magnetometer/hmc5843_i2c.c

@@ -59,8 +59,13 @@ static const struct regmap_config hmc5843_i2c_regmap_config = {
 static int hmc5843_i2c_probe(struct i2c_client *cli,
 			     const struct i2c_device_id *id)
 {
+	struct regmap *regmap = devm_regmap_init_i2c(cli,
+			&hmc5843_i2c_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
 	return hmc5843_common_probe(&cli->dev,
-			devm_regmap_init_i2c(cli, &hmc5843_i2c_regmap_config),
+			regmap,
 			id->driver_data, id->name);
 }
 

drivers/staging/iio/magnetometer/hmc5843_spi.c

@@ -59,6 +59,7 @@ static const struct regmap_config hmc5843_spi_regmap_config = {
 static int hmc5843_spi_probe(struct spi_device *spi)
 {
 	int ret;
+	struct regmap *regmap;
 	const struct spi_device_id *id = spi_get_device_id(spi);
 
 	spi->mode = SPI_MODE_3;
@@ -68,8 +69,12 @@ static int hmc5843_spi_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
+	regmap = devm_regmap_init_spi(spi, &hmc5843_spi_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
 	return hmc5843_common_probe(&spi->dev,
-			devm_regmap_init_spi(spi, &hmc5843_spi_regmap_config),
+			regmap,
 			id->driver_data, id->name);
 }