hwmon: (mlxreg-fan) Return zero speed for broken fan

Currently for broken fan driver returns value calculated based on error
code (0xFF) in related fan speed register.
Thus, for such fan user gets fan{n}_fault to 1 and fan{n}_input with
misleading value.

Add check for fan fault prior return speed value and return zero if
fault is detected.

Fixes: 65afb4c8e7e4 ("hwmon: (mlxreg-fan) Add support for Mellanox FAN driver")
Signed-off-by: Vadim Pasternak <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>

diff --git a/drivers/hwmon/mlxreg-fan.c b/drivers/hwmon/mlxreg-fan.c
index b48bd7c961d665c4bab51f627f524f88ae415cf6..96017cc8da7ecd5b79e9068bccce9be1315f674e 100644 (file)
--- a/drivers/hwmon/mlxreg-fan.c
+++ b/drivers/hwmon/mlxreg-fan.c
@@ -155,6 +155,12 @@ mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
                        if (err)
                                return err;
 
+                       if (MLXREG_FAN_GET_FAULT(regval, tacho->mask)) {
+                               /* FAN is broken - return zero for FAN speed. */
+                               *val = 0;
+                               return 0;
+                       }
+
                        *val = MLXREG_FAN_GET_RPM(regval, fan->divider,
                                                  fan->samples);
                        break;