PM / OPP: Pass opp_table to dev_pm_opp_put_regulator()

Joonyoung Shim reported an interesting problem on his ARM octa-core
Odoroid-XU3 platform. During system suspend, dev_pm_opp_put_regulator()
was failing for a struct device for which dev_pm_opp_set_regulator() is
called earlier.

This happened because an earlier call to
dev_pm_opp_of_cpumask_remove_table() function (from cpufreq-dt.c file)
removed all the entries from opp_table->dev_list apart from the last CPU
device in the cpumask of CPUs sharing the OPP.

But both dev_pm_opp_set_regulator() and dev_pm_opp_put_regulator()
routines get CPU device for the first CPU in the cpumask. And so the OPP
core failed to find the OPP table for the struct device.

This patch attempts to fix this problem by returning a pointer to the
opp_table from dev_pm_opp_set_regulator() and using that as the
parameter to dev_pm_opp_put_regulator(). This ensures that the
dev_pm_opp_put_regulator() doesn't fail to find the opp table.

Note that similar design problem also exists with other
dev_pm_opp_put_*() APIs, but those aren't used currently by anyone and
so we don't need to update them for now.

Cc: 4.4+ <stable@vger.kernel.org> # 4.4+
Reported-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ Viresh: Wrote commit log and tested on exynos 5250 ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 6 insertions, 16 deletions

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 4c7c6da..2824d3a 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -1316,7 +1316,7 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_put_prop_name);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex cannot be locked.
  */
-int dev_pm_opp_set_regulator(struct device *dev, const char *name)
+struct opp_table *dev_pm_opp_set_regulator(struct device *dev, const char *name)
 {
 	struct opp_table *opp_table;
 	struct regulator *reg;
@@ -1354,20 +1354,20 @@ int dev_pm_opp_set_regulator(struct device *dev, const char *name)
 	opp_table->regulator = reg;
 
 	mutex_unlock(&opp_table_lock);
-	return 0;
+	return opp_table;
 
 err:
 	_remove_opp_table(opp_table);
 unlock:
 	mutex_unlock(&opp_table_lock);
 
-	return ret;
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulator);
 
 /**
  * dev_pm_opp_put_regulator() - Releases resources blocked for regulator
- * @dev: Device for which regulator was set.
+ * @opp_table: OPP table returned from dev_pm_opp_set_regulator().
  *
  * Locking: The internal opp_table and opp structures are RCU protected.
  * Hence this function internally uses RCU updater strategy with mutex locks
@@ -1375,22 +1375,12 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulator);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex cannot be locked.
  */
-void dev_pm_opp_put_regulator(struct device *dev)
+void dev_pm_opp_put_regulator(struct opp_table *opp_table)
 {
-	struct opp_table *opp_table;
-
 	mutex_lock(&opp_table_lock);
 
-	/* Check for existing table for 'dev' first */
-	opp_table = _find_opp_table(dev);
-	if (IS_ERR(opp_table)) {
-		dev_err(dev, "Failed to find opp_table: %ld\n",
-			PTR_ERR(opp_table));
-		goto unlock;
-	}
-
 	if (IS_ERR(opp_table->regulator)) {
-		dev_err(dev, "%s: Doesn't have regulator set\n", __func__);
+		pr_err("%s: Doesn't have regulator set\n", __func__);
 		goto unlock;
 	}