From d8b8facdd0462c280d92bae7b792924cd6647c48 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 24 Jul 2021 17:07:30 +1000
Subject: [PATCH] HAL_ChibiOS: fixed off by 1 bug in GPIO check

---
 libraries/AP_HAL_ChibiOS/GPIO.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/AP_HAL_ChibiOS/GPIO.cpp b/libraries/AP_HAL_ChibiOS/GPIO.cpp
index 39be31eb3b..e24c24729a 100644
--- a/libraries/AP_HAL_ChibiOS/GPIO.cpp
+++ b/libraries/AP_HAL_ChibiOS/GPIO.cpp
@@ -80,7 +80,7 @@ void GPIO::init()
     for (uint8_t i=0; i<ARRAY_SIZE(_gpio_tab); i++) {
         struct gpio_entry *g = &_gpio_tab[i];
         if (g->pwm_num != 0) {
-            g->enabled = SRV_Channels::is_GPIO(g->pwm_num+chan_offset);
+            g->enabled = SRV_Channels::is_GPIO((g->pwm_num-1)+chan_offset);
         }
     }
 #endif // HAL_BOOTLOADER_BUILD