diff --git a/drivers/button/button-qcom-pmic.c b/drivers/button/button-qcom-pmic.c
index 34a976d..e778e51 100644
--- a/drivers/button/button-qcom-pmic.c
+++ b/drivers/button/button-qcom-pmic.c
@@ -86,7 +86,7 @@
 	}
 
 	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;
 	}