[PATCH 07/15] thermal/drivers/samsung: acpm-tmu: Return -ENODATA when sensor is disabled

[Tudor Ambarus]

In the thermal core, returning -EAGAIN from .get_temp() instructs
__thermal_zone_device_update() -> thermal_zone_recheck() to schedule a
250 ms (4 Hz) retry loop with no backoff. If re-enabling a sensor fails
(for example on resume, or after an acpm_tmu_update_thresholds() failure
when polling is active), sensor->enabled remains false while tz->mode is
still THERMAL_DEVICE_ENABLED, causing an infinite 4 Hz retry loop
instead of backing off and disabling the broken zone via
thermal_zone_broken_disable(). In addition, hwmon's temp_input_show()
forwards -EAGAIN directly to userspace rather than -ENODATA.

Return -ENODATA instead of -EAGAIN when !sensor->enabled in
acpm_tmu_get_temp().

Fixes: 50a2c5d4062a ("thermal/drivers/samsung: Add Exynos ACPM TMU driver GS101")
Signed-off-by: Tudor Ambarus <tudor.ambarus at linaro.org>
---
 drivers/thermal/samsung/acpm-tmu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/samsung/acpm-tmu.c b/drivers/thermal/samsung/acpm-tmu.c
index 4257bec802c1..1f56c69af76f 100644
--- a/drivers/thermal/samsung/acpm-tmu.c
+++ b/drivers/thermal/samsung/acpm-tmu.c
@@ -200,7 +200,7 @@ static int acpm_tmu_get_temp(struct thermal_zone_device *tz, int *temp)
 	 * after PM resume.
 	 */
 	if (!sensor->enabled)
-		return -EAGAIN;
+		return -ENODATA;
 
 	ret = pm_runtime_resume_and_get(dev);
 	if (ret < 0)
@@ -208,7 +208,7 @@ static int acpm_tmu_get_temp(struct thermal_zone_device *tz, int *temp)
 
 	scoped_guard(mutex, &sensor->lock) {
 		if (!sensor->enabled) {
-			ret = -EAGAIN;
+			ret = -ENODATA;
 		} else {
 			ret = ops->read_temp(handle, priv->mbox_chan_id,
 					     sensor->group->id, &acpm_temp);

-- 
2.56.0.257.gf7497c7d27-goog