coresight: cti: Add PM runtime call in enable_store

In commit 6746eae ("coresight: cti: Fix hang in cti_disable_hw()")
PM runtime calls are removed from cti_enable_hw/cti_disable_hw. When
enabling CTI by writing enable sysfs node, clock for accessing CTI
register won't be enabled. Device will crash due to register access
issue. Add PM runtime call in enable_store to fix this issue.

Fixes: 6746eae ("coresight: cti: Fix hang in cti_disable_hw()")
Signed-off-by: Mao Jinlong <quic_jinlmao@quicinc.com>
[Change to only call pm_runtime_put if a disable happened]
Tested-by: Jinlong Mao <quic_jinlmao@quicinc.com>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230110110736.2709917-3-james.clark@arm.com

drivers/hwtracing/coresight/coresight-cti-sysfs.c

@@ -108,10 +108,19 @@ static ssize_t enable_store(struct device *dev,
 	if (ret)
 		return ret;
 
-	if (val)
+	if (val) {
+		ret = pm_runtime_resume_and_get(dev->parent);
+		if (ret)
+			return ret;
 		ret = cti_enable(drvdata->csdev);
-	else
+		if (ret)
+			pm_runtime_put(dev->parent);
+	} else {
 		ret = cti_disable(drvdata->csdev);
+		if (!ret)
+			pm_runtime_put(dev->parent);
+	}
+
 	if (ret)
 		return ret;
 	return size;