hwmon: (peci/cputemp) Fix crit_hyst returning delta instead of absolute temperature

The hwmon sysfs ABI expects tempN_crit_hyst to report the temperature at
which the critical condition clears, not the hysteresis delta from the
critical limit.

The peci cputemp driver currently returns tjmax - tcontrol for
crit_hyst_type, which is the hysteresis margin rather than the
corresponding absolute temperature.

Return tcontrol directly, and update the documentation accordingly.

Fixes: bf3608f ("hwmon: peci: Add cputemp driver")
Cc: [email protected]
Signed-off-by: Sanman Pradhan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guenter Roeck <[email protected]>

Author: Sanman Pradhan

Documentation/hwmon/peci-cputemp.rst

@@ -51,8 +51,9 @@ temp1_max		Provides thermal control temperature of the CPU package
 temp1_crit		Provides shutdown temperature of the CPU package which
 			is also known as the maximum processor junction
 			temperature, Tjmax or Tprochot.
-temp1_crit_hyst		Provides the hysteresis value from Tcontrol to Tjmax of
-			the CPU package.
+temp1_crit_hyst		Provides the hysteresis temperature of the CPU
+			package. Returns Tcontrol, the temperature at which
+			the critical condition clears.
 
 temp2_label		"DTS"
 temp2_input		Provides current temperature of the CPU package scaled
@@ -62,8 +63,9 @@ temp2_max		Provides thermal control temperature of the CPU package
 temp2_crit		Provides shutdown temperature of the CPU package which
 			is also known as the maximum processor junction
 			temperature, Tjmax or Tprochot.
-temp2_crit_hyst		Provides the hysteresis value from Tcontrol to Tjmax of
-			the CPU package.
+temp2_crit_hyst		Provides the hysteresis temperature of the CPU
+			package. Returns Tcontrol, the temperature at which
+			the critical condition clears.
 
 temp3_label		"Tcontrol"
 temp3_input		Provides current Tcontrol temperature of the CPU

drivers/hwmon/peci/cputemp.c

@@ -131,7 +131,7 @@ static int get_temp_target(struct peci_cputemp *priv, enum peci_temp_target_type
 		*val = priv->temp.target.tjmax;
 		break;
 	case crit_hyst_type:
-		*val = priv->temp.target.tjmax - priv->temp.target.tcontrol;
+		*val = priv->temp.target.tcontrol;
 		break;
 	default:
 		ret = -EOPNOTSUPP;