thermal: core: Store trip pointer in struct thermal_instance

Replace the integer trip number stored in struct thermal_instance with
a pointer to the relevant trip and adjust the code using the structure
in question accordingly.

The main reason for making this change is to allow the trip point to
cooling device binding code more straightforward, as illustrated by
subsequent modifications of the ACPI thermal driver, but it also helps
to clarify the overall design and allows the governor code overhead to
be reduced (through subsequent modifications).

The only case in which it adds complexity is trip_point_show() that
needs to walk the trips[] table to find the index of the given trip
point, but this is not a critical path and the interface that
trip_point_show() belongs to is problematic anyway (for instance, it
doesn't cover the case when the same cooling devices is associated
with multiple trip points).

This is a preliminary change and the affected code will be refined by
a series of subsequent modifications of thermal governors, the core and
the ACPI thermal driver.

The general functionality is not expected to be affected by this change.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/thermal/thermal_trip.c b/drivers/thermal/thermal_trip.c
index 1cadb3b5d104..a8e92a89b2b8 100644
--- a/drivers/thermal/thermal_trip.c
+++ b/drivers/thermal/thermal_trip.c
@@ -157,3 +157,18 @@ int thermal_zone_set_trip(struct thermal_zone_device *tz, int trip_id,
 
 	return 0;
 }
+
+int thermal_zone_trip_id(struct thermal_zone_device *tz,
+			 const struct thermal_trip *trip)
+{
+	int i;
+
+	lockdep_assert_held(&tz->lock);
+
+	for (i = 0; i < tz->num_trips; i++) {
+		if (&tz->trips[i] == trip)
+			return i;
+	}
+
+	return -ENODATA;
+}