thermal: allow registering without .get_temp
Eduardo Valentin [Fri, 14 Feb 2014 00:18:24 +0000 (16:18 -0800)]
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.

Change-Id: I1ff78dc306f24a42ab5f3930992033301cd054d9
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>
Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com> # for the NVIDIA downstream kernel
Reviewed-on: http://git-master/r/356893
Reviewed-by: Matthew Longnecker <mlongnecker@nvidia.com>
Reviewed-by: Diwakar Tundlam <dtundlam@nvidia.com>
Tested-by: Diwakar Tundlam <dtundlam@nvidia.com>

drivers/thermal/thermal_core.c

index 823c3c5..a0e693d 100644 (file)
@@ -417,7 +417,7 @@ 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);
@@ -470,6 +470,9 @@ 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++)
@@ -1527,7 +1530,7 @@ 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 || !ops->get_trip_temp))
@@ -1660,6 +1663,9 @@ 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);
 
        dev_info(&tz->device, "Registering thermal zone %s for type %s\n",