hwmon: (lm90) Support the extra resolution bits of MAX6657

The Maxim MAX6657, MAX6658 and MAX6659 have extra resolution bits for
the local temperature measurement. Let the lm90 driver read them and
export them to user-space.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Martyn Welch <martyn.welch@gefanuc.com>

Documentation/hwmon/lm90

@@ -86,9 +86,8 @@ family is that it features critical limits with hysteresis, and an
 increased resolution of the remote temperature measurement.
 
 The different chipsets of the family are not strictly identical, although
-very similar. This driver doesn't handle any specific feature for now,
-with the exception of SMBus PEC. For reference, here comes a non-exhaustive
-list of specific features:
+very similar. For reference, here comes a non-exhaustive list of specific
+features:
 
 LM90:
   * Filter and alert configuration register at 0xBF.
@@ -114,9 +113,11 @@ ADT7461:
   * Lower resolution for remote temperature
 
 MAX6657 and MAX6658:
+  * Better local resolution
   * Remote sensor type selection
 
 MAX6659:
+  * Better local resolution
   * Selectable address
   * Second critical temperature limit
   * Remote sensor type selection
@@ -127,7 +128,8 @@ MAX6680 and MAX6681:
 
 All temperature values are given in degrees Celsius. Resolution
 is 1.0 degree for the local temperature, 0.125 degree for the remote
-temperature.
+temperature, except for the MAX6657, MAX6658 and MAX6659 which have a
+resolution of 0.125 degree for both temperatures.
 
 Each sensor has its own high and low limits, plus a critical limit.
 Additionally, there is a relative hysteresis value common to both critical

drivers/hwmon/lm90.c

@@ -149,6 +149,10 @@ I2C_CLIENT_INSMOD_7(lm90, adm1032, lm99, lm86, max6657, adt7461, max6680);
 #define LM90_REG_R_TCRIT_HYST		0x21
 #define LM90_REG_W_TCRIT_HYST		0x21
 
+/* MAX6657-specific registers */
+
+#define MAX6657_REG_R_LOCAL_TEMPL	0x11
+
 /*
  * Conversions and various macros
  * For local temperatures and limits, critical limits and the hysteresis
@@ -239,15 +243,15 @@ struct lm90_data {
 	int kind;
 
 	/* registers values */
-	s8 temp8[5];	/* 0: local input
-			   1: local low limit
-			   2: local high limit
-			   3: local critical limit
-			   4: remote critical limit */
-	s16 temp11[4];	/* 0: remote input
+	s8 temp8[4];	/* 0: local low limit
+			   1: local high limit
+			   2: local critical limit
+			   3: remote critical limit */
+	s16 temp11[5];	/* 0: remote input
 			   1: remote low limit
 			   2: remote high limit
-			   3: remote offset (except max6657) */
+			   3: remote offset (except max6657)
+			   4: local input */
 	u8 temp_hyst;
 	u8 alarms; /* bitvector */
 };
@@ -285,7 +289,7 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
 		data->temp8[nr] = TEMP1_TO_REG_ADT7461(val);
 	else
 		data->temp8[nr] = TEMP1_TO_REG(val);
-	i2c_smbus_write_byte_data(client, reg[nr - 1], data->temp8[nr]);
+	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
 	mutex_unlock(&data->update_lock);
 	return count;
 }
@@ -347,7 +351,7 @@ static ssize_t set_temphyst(struct device *dev, struct device_attribute *dummy,
 	long hyst;
 
 	mutex_lock(&data->update_lock);
-	hyst = TEMP1_FROM_REG(data->temp8[3]) - val;
+	hyst = TEMP1_FROM_REG(data->temp8[2]) - val;
 	i2c_smbus_write_byte_data(client, LM90_REG_W_TCRIT_HYST,
 				  HYST_TO_REG(hyst));
 	mutex_unlock(&data->update_lock);
@@ -371,23 +375,23 @@ static ssize_t show_alarm(struct device *dev, struct device_attribute
 	return sprintf(buf, "%d\n", (data->alarms >> bitnr) & 1);
 }
 
-static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp8, NULL, 0);
+static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp11, NULL, 4);
 static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp11, NULL, 0);
 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp8,
-	set_temp8, 1);
+	set_temp8, 0);
 static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp11,
 	set_temp11, 1);
 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp8,
-	set_temp8, 2);
+	set_temp8, 1);
 static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp11,
 	set_temp11, 2);
 static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp8,
-	set_temp8, 3);
+	set_temp8, 2);
 static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp8,
-	set_temp8, 4);
+	set_temp8, 3);
 static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temphyst,
-	set_temphyst, 3);
-static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 4);
+	set_temphyst, 2);
+static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_temphyst, NULL, 3);
 static SENSOR_DEVICE_ATTR(temp2_offset, S_IWUSR | S_IRUGO, show_temp11,
 	set_temp11, 3);
 
@@ -779,13 +783,21 @@ static struct lm90_data *lm90_update_device(struct device *dev)
 		u8 h, l;
 
 		dev_dbg(&client->dev, "Updating lm90 data.\n");
-		lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
-		lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[1]);
-		lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[2]);
-		lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[3]);
-		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
+		lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[0]);
+		lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[1]);
+		lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[2]);
+		lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[3]);
 		lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
 
+		if (data->kind == max6657) {
+			lm90_read16(client, LM90_REG_R_LOCAL_TEMP,
+				    MAX6657_REG_R_LOCAL_TEMPL,
+				    &data->temp11[4]);
+		} else {
+			if (lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP,
+					  &h) == 0)
+				data->temp11[4] = h << 8;
+		}
 		lm90_read16(client, LM90_REG_R_REMOTE_TEMPH,
 			    LM90_REG_R_REMOTE_TEMPL, &data->temp11[0]);