thermal: trace: Trace temperature changes

Create a new event to trace the temperature of a thermal zone. Using
this event trace the temperature changes of the thermal zone every-time
it is updated.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/thermal_core.c

@@ -38,6 +38,9 @@
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/thermal.h>
+
 #include "thermal_core.h"
 #include "thermal_hwmon.h"
 
@@ -463,6 +466,7 @@ static void update_temperature(struct thermal_zone_device *tz)
 	tz->temperature = temp;
 	mutex_unlock(&tz->lock);
 
+	trace_thermal_temperature(tz);
 	dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n",
 				tz->last_temperature, tz->temperature);
 }

include/trace/events/thermal.h

@@ -0,0 +1,38 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM thermal
+
+#if !defined(_TRACE_THERMAL_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_THERMAL_H
+
+#include <linux/thermal.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(thermal_temperature,
+
+	TP_PROTO(struct thermal_zone_device *tz),
+
+	TP_ARGS(tz),
+
+	TP_STRUCT__entry(
+		__string(thermal_zone, tz->type)
+		__field(int, id)
+		__field(int, temp_prev)
+		__field(int, temp)
+	),
+
+	TP_fast_assign(
+		__assign_str(thermal_zone, tz->type);
+		__entry->id = tz->id;
+		__entry->temp_prev = tz->last_temperature;
+		__entry->temp = tz->temperature;
+	),
+
+	TP_printk("thermal_zone=%s id=%d temp_prev=%d temp=%d",
+		__get_str(thermal_zone), __entry->id, __entry->temp_prev,
+		__entry->temp)
+);
+
+#endif /* _TRACE_THERMAL_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>