mfd: arizona: Fix undefined behavior

When the driver is used with a subdevice that is disabled in the
kernel configuration, clang gets a little confused about the
control flow and fails to notice that n_subdevs is only
uninitialized when subdevs is NULL, and we check for that,
leading to a false-positive warning:

drivers/mfd/arizona-core.c:1423:19: error: variable 'n_subdevs' is uninitialized when used here
      [-Werror,-Wuninitialized]
                              subdevs, n_subdevs, NULL, 0, NULL);
                                       ^~~~~~~~~
drivers/mfd/arizona-core.c:999:15: note: initialize the variable 'n_subdevs' to silence this warning
        int n_subdevs, ret, i;
                     ^
                      = 0

Ideally, we would rearrange the code to avoid all those early
initializations and have an explicit exit in each disabled case,
but it's much easier to chicken out and add one more initialization
here to shut up the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/arizona-core.c b/drivers/mfd/arizona-core.c
index 27b61639cdc7e7073d7bf3cd5247ac371a75c37c..0ca0fc9a67fd9bf5e64074d5688ace009f031156 100644 (file)
--- a/drivers/mfd/arizona-core.c
+++ b/drivers/mfd/arizona-core.c
@@ -996,7 +996,7 @@ int arizona_dev_init(struct arizona *arizona)
        unsigned int reg, val;
        int (*apply_patch)(struct arizona *) = NULL;
        const struct mfd_cell *subdevs = NULL;
-       int n_subdevs, ret, i;
+       int n_subdevs = 0, ret, i;
 
        dev_set_drvdata(arizona->dev, arizona);
        mutex_init(&arizona->clk_lock);