---
 .../driver-api/thermal/sysfs-api.rst          |  1 +
 drivers/thermal/thermal_sysfs.c               | 23 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
index 18140dbb1ce1..ed5e6ba4e0d7 100644
--- a/Documentation/driver-api/thermal/sysfs-api.rst
+++ b/Documentation/driver-api/thermal/sysfs-api.rst

@@ -358,6 +358,7 @@ Thermal zone device sys I/F, created once it's registered::
     |---stats:                 Directory containing thermal zone device's stats
     |---stats/reset_tz_stats:  Writes to this file resets the statistics.
     |---stats/max_gradient:    The maximum recorded dT/dt in uC/ms.
+    |---stats/min_gradient:    The minimum recorded dT/dt in uC/ms.

 Thermal cooling device sys I/F, created once it's registered::

diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c
index aa28c1cae916..f89ec9a7e8c8 100644
--- a/drivers/thermal/thermal_sysfs.c
+++ b/drivers/thermal/thermal_sysfs.c

@@ -542,6 +542,7 @@ static void destroy_trip_attrs(struct thermal_zone_device *tz)
 struct thermal_zone_device_stats {
        spinlock_t lock; /* protects this struct */
        s64 max_gradient;
+       s64 min_gradient;
        ktime_t last_time;
 };

@@ -569,6 +570,10 @@ static void temperature_stats_update(struct thermal_zone_device *tz)
        /* update fastest temperature rise from our perspective */
        if (cur_gradient > stats->max_gradient)
                stats->max_gradient = cur_gradient;
+
+       /* update fastest temperature decay from our perspective */
+       if (cur_gradient < stats->min_gradient)
+               stats->min_gradient = cur_gradient;
 }

 void thermal_zone_device_stats_update(struct thermal_zone_device *tz)

@@ -595,6 +600,21 @@ static ssize_t max_gradient_show(struct device *dev,
        return ret;
 }

+static ssize_t min_gradient_show(struct device *dev,
+                                struct device_attribute *attr, char *buf)
+{
+       struct thermal_zone_device *tz = to_thermal_zone(dev);
+       struct thermal_zone_device_stats *stats = tz->stats;
+       int ret;
+
+       spin_lock(&stats->lock);
+       temperature_stats_update(tz);
+       ret = snprintf(buf, PAGE_SIZE, "%lld\n", stats->min_gradient);
+       spin_unlock(&stats->lock);
+
+       return ret;
+}
+
 static ssize_t
 reset_tz_stats_store(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t count)

@@ -604,6 +624,7 @@ reset_tz_stats_store(struct device *dev, struct device_attribute *attr,

        spin_lock(&stats->lock);

+       stats->min_gradient = 0;
        stats->max_gradient = 0;
        stats->last_time = ktime_get();

@@ -612,10 +633,12 @@ reset_tz_stats_store(struct device *dev, struct device_attribute *attr,
        return count;
 }

+static DEVICE_ATTR_RO(min_gradient);
 static DEVICE_ATTR_RO(max_gradient);
 static DEVICE_ATTR_WO(reset_tz_stats);

 static struct attribute *thermal_zone_device_stats_attrs[] = {
+       &dev_attr_min_gradient.attr,
        &dev_attr_max_gradient.attr,
        &dev_attr_reset_tz_stats.attr,
        NULL
--

2.34.1