From 1783b3da55902431198a295560cc4a473aa711ad Mon Sep 17 00:00:00 2001
From: Guillaume Gonnet <Guillaume.Gonnet@grenoble-inp.org>
Date: Thu, 16 May 2019 20:12:22 +0200
Subject: [PATCH] drivers/ds18: fix `ds18_read` with negative temperatures
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When DS18 returns 0xFE6F (corresponding to -25.0625 °C), `ds18_read` returns
13877 whereas it should return -2506. This commit fixes this issue.
---
 drivers/ds18/ds18.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ds18/ds18.c b/drivers/ds18/ds18.c
index 43b0d71b1d..f1ea75583f 100644
--- a/drivers/ds18/ds18.c
+++ b/drivers/ds18/ds18.c
@@ -184,7 +184,7 @@ int ds18_read(const ds18_t *dev, int16_t *temperature)
 
     DEBUG("[DS18] Received byte: 0x%02x\n", b2);
 
-    int32_t measurement = ((int32_t)(b2 << 8 | b1) * 625);
+    int32_t measurement = ((int16_t)(b2 << 8 | b1) * 625);
     *temperature = (int16_t)(measurement / 100);
 
     return DS18_OK;