1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/i2c/chips/lm75.h b/drivers/i2c/chips/lm75.h
new file mode 100644
index 000000000000..63e3f2fb4c21
--- /dev/null
+++ b/drivers/i2c/chips/lm75.h
@@ -0,0 +1,49 @@
+/*
+    lm75.h - Part of lm_sensors, Linux kernel modules for hardware
+             monitoring
+    Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+/*
+    This file contains common code for encoding/decoding LM75 type
+    temperature readings, which are emulated by many of the chips
+    we support.  As the user is unlikely to load more than one driver
+    which contains this code, we don't worry about the wasted space.
+*/
+
+#include <linux/i2c-sensor.h>
+
+/* straight from the datasheet */
+#define LM75_TEMP_MIN (-55000)
+#define LM75_TEMP_MAX 125000
+
+/* TEMP: 0.001C/bit (-55C to +125C)
+   REG: (0.5C/bit, two's complement) << 7 */
+static inline u16 LM75_TEMP_TO_REG(int temp)
+{
+	int ntemp = SENSORS_LIMIT(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
+	ntemp += (ntemp<0 ? -250 : 250);
+	return (u16)((ntemp / 500) << 7);
+}
+
+static inline int LM75_TEMP_FROM_REG(u16 reg)
+{
+	/* use integer division instead of equivalent right shift to
+	   guarantee arithmetic shift and preserve the sign */
+	return ((s16)reg / 128) * 500;
+}
+