[PATCH 08/13] thermal: Allow sensor ops to fail with -ENOSYS

Sascha Hauer
2015-03-26T15:54:22Z

The thermal core uses the existence of the .get_temp, .get_trend and
.set_emul_temp to detect whether this operation exists and should be
used or whether it should be emulated in software. This makes problems
for of-thermal which has to modify the struct thermal_zone_device_ops
during runtime whenever a sensor is registered or unregistered.

Let the core test for -ENOSYS from these callbacks and treat it like
if the callbacks were not present.

This allows of-thermal to always set the sensor related callbacks and
to make struct thermal_zone_device_ops const again.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
drivers/thermal/thermal_core.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 6d0fdad..acf00b5 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -413,10 +413,13 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
*/
int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
{
- int ret = -EINVAL;
+ int ret;

- if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
- goto exit;
+ if (!tz || IS_ERR(tz))
+ return -EINVAL;
+
+ if (!tz->ops->get_temp)
+ return -ENOSYS;

mutex_lock(&tz->lock);

@@ -426,7 +429,7 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
*temp = tz->emul_temperature;

mutex_unlock(&tz->lock);
-exit:
+
return ret;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
@@ -437,10 +440,11 @@ void thermal_zone_device_update(struct thermal_zone_device *tz)
unsigned long temp;
int ret;

- if (!tz->ops->get_temp)
+ ret = thermal_zone_get_temp(tz, &temp);
+
+ if (ret == -ENOSYS)
return;

- ret = thermal_zone_get_temp(tz, &temp);
if (ret) {
dev_warn(&tz->device, "failed to read out thermal zone %d\n",
tz->id);
@@ -788,12 +792,16 @@ emul_temp_store(struct device *dev, struct device_attribute *attr,
}
}

- if (!tz->ops->set_emul_temp) {
+ if (tz->ops->set_emul_temp)
+ ret = tz->ops->set_emul_temp(tz, temperature);
+ else
+ ret = -ENOSYS;
+
+ if (ret == -ENOSYS) {
mutex_lock(&tz->lock);
tz->emul_temperature = temperature;
mutex_unlock(&tz->lock);
- } else {
- ret = tz->ops->set_emul_temp(tz, temperature);
+ ret = 0;
}

if (!ret)
--
2.1.4