[PATCH] button: qcom-pmic: fix some error checking

[Dan Carpenter]

The pmic_reg_read() function can return errors.  Add a check for that.

Fixes: 4e8aa0065d4b ("button: qcom-pmic: introduce Qualcomm PMIC button driver")
Signed-off-by: Dan Carpenter <dan.carpen...@linaro.org>
---
This patch is mostly to make static checkers happy but it's obvious and
harmless.

 drivers/button/button-qcom-pmic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/button/button-qcom-pmic.c 
b/drivers/button/button-qcom-pmic.c
index 34a976d1e6c6..e778e51a4f36 100644
--- a/drivers/button/button-qcom-pmic.c
+++ b/drivers/button/button-qcom-pmic.c
@@ -86,7 +86,7 @@ static int qcom_pwrkey_probe(struct udevice *dev)
        }
 
        ret = pmic_reg_read(priv->pmic, priv->base + REG_SUBTYPE);
-       if ((ret & 0x7) == 0) {
+       if (ret < 0 || (ret & 0x7) == 0) {
                printf("%s: unexpected PMCI function subtype %d\n", dev->name, 
ret);
                return -ENXIO;
        }
-- 
2.43.0