This function is supposed to return zero on success or negative error
codes on error.  Unfortunately, there is a bug so it sometimes returns
non-zero, positive numbers on success.

I noticed this bug during review and I can't test it.  It does appear
that the return is sometimes propogated back to _regmap_read() where all
non-zero returns are treated as failure so this may affect run time.

Fixes: 47c1697508f2 ("mfd: Align ab8500 with the abx500 interface")
Signed-off-by: Dan Carpenter <redacted>
---
v2: In v1, I introduced an new error path and forgot to drop the lock.

 drivers/mfd/ab8500-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/ab8500-core.c b/drivers/mfd/ab8500-core.c
index 30d09d177171..11ab17f64c64 100644
--- a/drivers/mfd/ab8500-core.c
+++ b/drivers/mfd/ab8500-core.c

@@ -261,7 +261,7 @@ static int get_register_interruptible(struct ab8500 *ab8500, u8 bank,
 	mutex_unlock(&ab8500->lock);
 	dev_vdbg(ab8500->dev, "rd: addr %#x => data %#x\n", addr, ret);
 
-	return ret;
+	return (ret < 0) ? ret : 0;
 }
 
 static int ab8500_get_register(struct device *dev, u8 bank,