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>

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index f1d511a9475b4dc29ec28864cb3b948e8ba13183..0e43dc208fc6d40c1f722f95828551890da68efe 100644 (file)
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -403,7 +403,7 @@ 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);
@@ -456,6 +456,9 @@ 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++)
@@ -1386,7 +1389,7 @@ 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))
@@ -1490,6 +1493,9 @@ 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)