diff --git a/Documentation/hwmon/lm77 b/Documentation/hwmon/lm77
index 57c3a46d6370..bfc915fe3639 100644
--- a/Documentation/hwmon/lm77
+++ b/Documentation/hwmon/lm77
@@ -18,5 +18,21 @@ sensor incorporates a band-gap type temperature sensor,
 10-bit ADC, and a digital comparator with user-programmable upper
 and lower limit values.
 
-Limits can be set through the Overtemperature Shutdown register and
-Hysteresis register.
+The LM77 implements 3 limits: low (temp1_min), high (temp1_max) and
+critical (temp1_crit.) It also implements an hysteresis mechanism which
+applies to all 3 limits. The relative difference is stored in a single
+register on the chip, which means that the relative difference between
+the limit and its hysteresis is always the same for all 3 limits.
+
+This implementation detail implies the following:
+* When setting a limit, its hysteresis will automatically follow, the
+  difference staying unchanged. For example, if the old critical limit
+  was 80 degrees C, and the hysteresis was 75 degrees C, and you change
+  the critical limit to 90 degrees C, then the hysteresis will
+  automatically change to 85 degrees C.
+* All 3 hysteresis can't be set independently. We decided to make
+  temp1_crit_hyst writable, while temp1_min_hyst and temp1_max_hyst are
+  read-only. Setting temp1_crit_hyst writes the difference between
+  temp1_crit_hyst and temp1_crit into the chip, and the same relative
+  hysteresis applies automatically to the low and high limits.
+* The limits should be set before the hysteresis.
diff --git a/drivers/hwmon/lm77.c b/drivers/hwmon/lm77.c
index 4cd8a513c47b..85e5b3355be4 100644
--- a/drivers/hwmon/lm77.c
+++ b/drivers/hwmon/lm77.c
@@ -216,13 +216,11 @@ static ssize_t set_temp_crit_hyst(struct device *dev,
 	return count;
 }
 
-/* preserve hysteresis when setting T_crit */
 static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr,
 			     const char *buf, size_t count)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct lm77_data *data = i2c_get_clientdata(client);
-	int oldcrithyst;
 	unsigned long val;
 	int err;
 
@@ -231,13 +229,9 @@ static ssize_t set_temp_crit(struct device *dev, struct device_attribute *attr,
 		return err;
 
 	mutex_lock(&data->update_lock);
-	oldcrithyst = data->temp_crit - data->temp_hyst;
 	data->temp_crit = val;
-	data->temp_hyst = data->temp_crit - oldcrithyst;
 	lm77_write_value(client, LM77_REG_TEMP_CRIT,
 			 LM77_TEMP_TO_REG(data->temp_crit));
-	lm77_write_value(client, LM77_REG_TEMP_HYST,
-			 LM77_TEMP_TO_REG(data->temp_hyst));
 	mutex_unlock(&data->update_lock);
 	return count;
 }