[PATCH 3/9] iio: adc: ad7768-1: reject devices without match data

[Jiale Yao]

SPI driver_override allows a device to bind to this driver without
matching either the OF or SPI device ID table. In that case,
spi_get_device_match_data() returns NULL.

ad7768_probe() later dereferences the returned chip information to
initialize the IIO channels and device name, causing a NULL pointer
dereference.

Commit 572a00852635 ("iio: dac: ad5686: missing NULL check on match
data") fixed the same driver_override issue in another SPI driver.
Reject devices without match data before continuing the probe.

Fixes: fa087f5babbc ("iio: adc: ad7768-1: introduce chip info for future multidevice support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
---
 drivers/iio/adc/ad7768-1.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index e9060c1bbe6f..3972821c295a 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -1829,6 +1829,9 @@ static int ad7768_probe(struct spi_device *spi)
 	}
 
 	st->chip = spi_get_device_match_data(spi);
+	if (!st->chip)
+		return -ENODATA;
+
 	st->spi = spi;
 
 	st->regmap = devm_regmap_init_spi(spi, &ad7768_regmap_config);
-- 
2.34.1