thermal: core: Add sanity checks for polling_delay and passive_delay

If polling_delay is nonzero and passive_delay is greater than
polling_delay, the thermal zone temperature will be updated less
often when tz->passive is nonzero, which is not as expected.  Make
the thermal zone registration fail with -EINVAL in that case as
this is a clear thermal zone configuration mistake.

If polling_delay is nonzero and passive_delay is 0, which is regarded
as a valid thermal zone configuration, the thermal zone will use polling
except when tz->passive is nonzero.  However, the expected behavior in
that case is to continue temperature polling with the same delay value
regardless of tz->passive, so set passive_delay to the polling_delay
value then.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/5802156.DvuYhMxLoT@rjwysocki.net

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 7139f729a83d4cf680cfba5e2f5ab661c0e9fcc1..24e0520340f67fa66f10dcd7f49b41264640ddc8 100644 (file)
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1390,6 +1390,14 @@ thermal_zone_device_register_with_trips(const char *type,
        if (num_trips > 0 && !trips)
                return ERR_PTR(-EINVAL);
 
+       if (polling_delay) {
+               if (passive_delay > polling_delay)
+                       return ERR_PTR(-EINVAL);
+
+               if (!passive_delay)
+                       passive_delay = polling_delay;
+       }
+
        if (!thermal_class)
                return ERR_PTR(-ENODEV);