From 5bfa7a8df43baa8087af60998dd37af9ca5ecd33 Mon Sep 17 00:00:00 2001
From: Valmantas Paliksa <walmis@gmail.com>
Date: Fri, 22 Mar 2019 07:10:57 -0600
Subject: [PATCH] drivers/ioexpander/gpio.c:  Return EINVAL if written value is
 not 0 nor 1.

---
 drivers/ioexpander/gpio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/ioexpander/gpio.c b/drivers/ioexpander/gpio.c
index c650def5d8..70ebcee20a 100644
--- a/drivers/ioexpander/gpio.c
+++ b/drivers/ioexpander/gpio.c
@@ -251,6 +251,10 @@ static ssize_t gpio_write(FAR struct file *filep, FAR const char *buffer,
         {
           val = 1;
         }
+      else
+        {
+          return -EINVAL;
+        }
 
       /* Write the GPIO value */