iio: adc: handle unknow of_device_id data

If we get an unknown 'childmode' value, a number of variables are not
initialized properly:

drivers/iio/adc/rcar-gyroadc.c: In function 'rcar_gyroadc_probe':
drivers/iio/adc/rcar-gyroadc.c:390:5: error: 'num_channels' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/iio/adc/rcar-gyroadc.c:426:22: error: 'sample_width' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/iio/adc/rcar-gyroadc.c:428:23: error: 'channels' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The driver is currently correct, but handling this properly is more robust
for possible modifications.

There is also a false-positive warning about adcmode being possibly uninitialized,
but that cannot happen as we also check the 'first' flag:

drivers/iio/adc/rcar-gyroadc.c:398:26: error: 'adcmode' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This adds an initialization for 'adcmode' and bails out for any unknown childmode.

Fixes: 059c53b32329 ("iio: adc: Add Renesas GyroADC driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/adc/rcar-gyroadc.c b/drivers/iio/adc/rcar-gyroadc.c
index 0c44f72c32a8592abd674410368e48e42aa77a13..018ed360e717cd619e89844225db1f374e1c2536 100644 (file)
--- a/drivers/iio/adc/rcar-gyroadc.c
+++ b/drivers/iio/adc/rcar-gyroadc.c
@@ -336,7 +336,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
        struct device_node *child;
        struct regulator *vref;
        unsigned int reg;
-       unsigned int adcmode, childmode;
+       unsigned int adcmode = -1, childmode;
        unsigned int sample_width;
        unsigned int num_channels;
        int ret, first = 1;
@@ -366,6 +366,8 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
                        channels = rcar_gyroadc_iio_channels_3;
                        num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
                        break;
+               default:
+                       return -EINVAL;
                }
 
                /*