From 3387ca5b425072b06c95831665ab9c9a63caf811 Mon Sep 17 00:00:00 2001
From: Daniele Cattaneo <daniele.cattaneo@alice.it>
Date: Sat, 14 Oct 2023 17:48:17 +0200
Subject: [PATCH] Do not crash when the STLink chip returns a voltage factor of
 zero.

---
 src/stlink-lib/usb.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/stlink-lib/usb.c b/src/stlink-lib/usb.c
index 30134e1..d3a57c3 100644
--- a/src/stlink-lib/usb.c
+++ b/src/stlink-lib/usb.c
@@ -238,7 +238,13 @@ int32_t _stlink_usb_target_voltage(stlink_t *sl) {
 
     factor = (rdata[3] << 24) | (rdata[2] << 16) | (rdata[1] << 8) | (rdata[0] << 0);
     reading = (rdata[7] << 24) | (rdata[6] << 16) | (rdata[5] << 8) | (rdata[4] << 0);
-    voltage = 2400 * reading / factor;
+    DLOG("target voltage factor=%08x reading=%08x\n", factor, reading);
+    if (factor != 0 && reading != 0) {
+        voltage = 2400 * reading / factor;
+    } else {
+        DLOG("voltage reading failed at device side, bad STLink chip?\n");
+        voltage = 0;
+    }
 
     return (voltage);
 }