[PATCH v2] thermal:core:fix: Check return code of the ->get_max_state() callback

[Lukasz Majewski <l.majewski@samsung.com>]

The return code from ->get_max_state() callback was not checked during
binding cooling device to thermal zone device.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
---
Changes for v2:
- It turned out that patches from 1 to 6 from v1 are not needed, since
  they either already solve the problem (like imx_thermal.c) or not use
  cpufreq as a thermal cooling device.
- The patch 7 from v1 is also not needed since this patch on error exits
  this function without using max_state variable.
- In thermal driver probe the cpufreq_cooling_register() method presence
  is crucial to evaluate if the thermal driver needs any actions with 
  -EPROBE_DEFER.
---
 drivers/thermal/thermal_core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 43b9070..8567929 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -928,7 +928,7 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
 	struct thermal_zone_device *pos1;
 	struct thermal_cooling_device *pos2;
 	unsigned long max_state;
-	int result;
+	int result, ret;
 
 	if (trip >= tz->trips || (trip < 0 && trip != THERMAL_TRIPS_NONE))
 		return -EINVAL;
@@ -945,7 +945,9 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
 	if (tz != pos1 || cdev != pos2)
 		return -EINVAL;
 
-	cdev->ops->get_max_state(cdev, &max_state);
+	ret = cdev->ops->get_max_state(cdev, &max_state);
+	if (ret)
+		return ret;
 
 	/* lower default 0, upper default max_state */
 	lower = lower == THERMAL_NO_LIMIT ? 0 : lower;
-- 
2.0.0.rc2