thermal: intel: int340x: Add throttling control interface to PTC

JIRA: https://issues.redhat.com/browse/RHEL-85463

commit 7954001
Author: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date:   Fri Jun 13 14:49:22 2025 -0700

    thermal: intel: int340x: Add throttling control interface to PTC

    Firmware-based thermal temperature control loops may aggressively
    throttle performance to prevent temperature overshoots relative to the
    defined target temperature. This can negatively impact performance. User
    space may prefer to prioritize performance, even if it results in
    temperature overshoots with in acceptable range.

    For example, user space might tolerate temperature overshoots when the
    device is placed on a desk, as opposed to when it's on a lap. To
    accommodate such scenarios, an optional attribute is provided to specify
    a tolerance level for temperature overshoots while maintaining acceptable
    performance.

    Attribute:

    thermal_tolerance: This attribute ranges from 0 to 7, where 0 represents
    the most aggressive control to avoid any temperature overshoots, and 7
    represents a more graceful approach, favoring performance even at the
    expense of temperature overshoots.
    Note: This level may not scale linearly. For example, a value of 3 does not
    necessarily imply a 50% improvement in performance compared to a value of 0.

    Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
    Reviewed-by: Zhang Rui <rui.zhang@intel.com>
    Link: https://patch.msgid.link/20250613214923.2910397-1-srinivas.pandruvada@linux.intel.com
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: David Arcari <darcari@redhat.com>

Author: darcari

Documentation/driver-api/thermal/intel_dptf.rst

@@ -206,6 +206,15 @@ All these controls needs admin privilege to update.
 	Update a new temperature target in milli degree celsius for hardware to
 	use for the temperature control.
 
+``thermal_tolerance`` (RW)
+	This attribute ranges from 0 to 7, where 0 represents
+	the most aggressive control to avoid any temperature overshoots, and
+	7 represents a more graceful approach, favoring performance even at
+	the expense of temperature overshoots.
+	Note: This level may not scale linearly. For example, a value of 3 does
+	not necessarily imply a 50% improvement in performance compared to a
+	value of 0.
+
 Given that this is platform temperature control, it is expected that a
 single user-level manager owns and manages the controls. If multiple
 user-level software applications attempt to write different targets, it

drivers/thermal/intel/int340x_thermal/platform_temperature_control.c

@@ -49,14 +49,15 @@ struct mmio_reg {
 };
 
 #define MAX_ATTR_GROUP_NAME_LEN	32
-#define PTC_MAX_ATTRS		3
+#define PTC_MAX_ATTRS		4
 
 struct ptc_data {
 	u32 offset;
 	struct attribute_group ptc_attr_group;
 	struct attribute *ptc_attrs[PTC_MAX_ATTRS];
 	struct device_attribute temperature_target_attr;
 	struct device_attribute enable_attr;
+	struct device_attribute thermal_tolerance_attr;
 	char group_name[MAX_ATTR_GROUP_NAME_LEN];
 };
 
@@ -78,6 +79,7 @@ static u32 ptc_offsets[PTC_MAX_INSTANCES] = {0x5B20, 0x5B28, 0x5B30};
 static const char * const ptc_strings[] = {
 	"temperature_target",
 	"enable",
+	"thermal_tolerance",
 	NULL
 };
 
@@ -177,6 +179,8 @@ PTC_SHOW(temperature_target);
 PTC_STORE(temperature_target);
 PTC_SHOW(enable);
 PTC_STORE(enable);
+PTC_SHOW(thermal_tolerance);
+PTC_STORE(thermal_tolerance);
 
 #define ptc_init_attribute(_name)\
 	do {\
@@ -193,9 +197,11 @@ static int ptc_create_groups(struct pci_dev *pdev, int instance, struct ptc_data
 
 	ptc_init_attribute(temperature_target);
 	ptc_init_attribute(enable);
+	ptc_init_attribute(thermal_tolerance);
 
 	data->ptc_attrs[index++] = &data->temperature_target_attr.attr;
 	data->ptc_attrs[index++] = &data->enable_attr.attr;
+	data->ptc_attrs[index++] = &data->thermal_tolerance_attr.attr;
 	data->ptc_attrs[index] = NULL;
 
 	snprintf(data->group_name, MAX_ATTR_GROUP_NAME_LEN,