thermal: allow registering without .get_temp

This patch changes the thermal core driver to allow
registration of thermal zones without the .get_temp callback.

The idea behind this change is to allow lazy registration
of sensor callbacks.

The thermal zone will be disabled whenever the ops
does not contain a .get_temp callback. The sysfs interface
will be returning -EINVAL on any temperature read operation.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
(cherry picked from commit 81bd4e1cebed5efb85bd94a15342ee4d6965a416)

Signed-off-by: Alex Shi <alex.shi@linaro.org>

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index d755440791b7ce0a01d3e186e423ed6769fcc8be..818cd787dbd2d058c8aacc303e8f9a04959b139e 100644 (file)
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -388,7 +388,7 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
        enum thermal_trip_type type;
 #endif
 
-       if (!tz || IS_ERR(tz))
+       if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
                goto exit;
 
        mutex_lock(&tz->lock);
@@ -441,6 +441,9 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
 {
        int count;
 
+       if (!tz->ops->get_temp)
+               return;
+
        update_temperature(tz);
 
        for (count = 0; count < tz->trips; count++)
@@ -1621,7 +1624,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
        if (trips > THERMAL_MAX_TRIPS || trips < 0 || mask >> trips)
                return ERR_PTR(-EINVAL);
 
-       if (!ops || !ops->get_temp)
+       if (!ops)
                return ERR_PTR(-EINVAL);
 
        if (trips > 0 && !ops->get_trip_type)
@@ -1723,6 +1726,9 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
 
        INIT_DELAYED_WORK(&(tz->poll_queue), thermal_zone_device_check);
 
+       if (!tz->ops->get_temp)
+               thermal_zone_device_set_polling(tz, 0);
+
        thermal_zone_device_update(tz);
 
        if (!result)