mlxsw: core: Add support for negative temperature readout

Extend macros MLXSW_REG_MTMP_TEMP_TO_MC() to allow support of negative
temperature readout, since chip and others thermal components are
capable of operating within the negative temperature.
With no such support negative temperature will be consider as very high
temperature and it will cause wrong readout and thermal shutdown.
For negative values 2`s complement is used.
Tested in chamber.
Example of chip ambient temperature readout with chamber temperature:
-10 Celsius:
temp1:             -6.0C  (highest =  -5.0C)
-5 Celsius:
temp1:             -1.0C  (highest =  -1.0C)

v2 (Andrew Lunn):
* Replace '%u' with '%d' in mlxsw_hwmon_module_temp_show()

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
index 504a34d240f7..35a1dc89c28a 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
@@ -312,7 +312,7 @@ static int mlxsw_thermal_get_temp(struct thermal_zone_device *tzdev,
 	struct mlxsw_thermal *thermal = tzdev->devdata;
 	struct device *dev = thermal->bus_info->dev;
 	char mtmp_pl[MLXSW_REG_MTMP_LEN];
-	unsigned int temp;
+	int temp;
 	int err;
 
 	mlxsw_reg_mtmp_pack(mtmp_pl, 0, false, false);
@@ -327,7 +327,7 @@ static int mlxsw_thermal_get_temp(struct thermal_zone_device *tzdev,
 		mlxsw_thermal_tz_score_update(thermal, tzdev, thermal->trips,
 					      temp);
 
-	*p_temp = (int) temp;
+	*p_temp = temp;
 	return 0;
 }
 
@@ -503,7 +503,7 @@ static int mlxsw_thermal_module_temp_get(struct thermal_zone_device *tzdev,
 	struct mlxsw_thermal *thermal = tz->parent;
 	struct device *dev = thermal->bus_info->dev;
 	char mtmp_pl[MLXSW_REG_MTMP_LEN];
-	unsigned int temp;
+	int temp;
 	int err;
 
 	/* Read module temperature. */
@@ -519,14 +519,14 @@ static int mlxsw_thermal_module_temp_get(struct thermal_zone_device *tzdev,
 		return 0;
 	}
 	mlxsw_reg_mtmp_unpack(mtmp_pl, &temp, NULL, NULL);
-	*p_temp = (int) temp;
+	*p_temp = temp;
 
 	if (!temp)
 		return 0;
 
 	/* Update trip points. */
 	err = mlxsw_thermal_module_trips_update(dev, thermal->core, tz);
-	if (!err)
+	if (!err && temp > 0)
 		mlxsw_thermal_tz_score_update(thermal, tzdev, tz->trips, temp);
 
 	return 0;
@@ -612,8 +612,8 @@ static int mlxsw_thermal_gearbox_temp_get(struct thermal_zone_device *tzdev,
 	struct mlxsw_thermal_module *tz = tzdev->devdata;
 	struct mlxsw_thermal *thermal = tz->parent;
 	char mtmp_pl[MLXSW_REG_MTMP_LEN];
-	unsigned int temp;
 	u16 index;
+	int temp;
 	int err;
 
 	index = MLXSW_REG_MTMP_GBOX_INDEX_MIN + tz->module;
@@ -627,7 +627,7 @@ static int mlxsw_thermal_gearbox_temp_get(struct thermal_zone_device *tzdev,
 	if (temp > 0)
 		mlxsw_thermal_tz_score_update(thermal, tzdev, tz->trips, temp);
 
-	*p_temp = (int) temp;
+	*p_temp = temp;
 	return 0;
 }