Re: [PATCH V2 01/16] PM / OPP: get/put regulators from OPP core

On 01/28, Viresh Kumar wrote:

+/**

• • dev_pm_opp_put_regulator() - Releases resources blocked for regulator
• • @dev: Device for which regulator was set.
• • Locking: The internal device_opp and opp structures are RCU protected.
• • Hence this function internally uses RCU updater strategy with mutex locks
• • to keep the integrity of the internal data structures. Callers should ensure
• • 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) +{

• struct device_opp *dev_opp;
• mutex_lock(&dev_opp_list_lock);
• /* Check for existing list for 'dev' first */
• dev_opp = _find_device_opp(dev);
• if (IS_ERR(dev_opp)) {

• dev_err(dev, "Failed to find dev_opp: %ld\n", PTR_ERR(dev_opp));
  

• goto unlock;
  

• }
• if (IS_ERR_OR_NULL(dev_opp->regulator)) {

• dev_err(dev, "%s: Doesn't have regulator set\n", __func__);
  

• goto unlock;
  

• }
• /* Make sure there are no concurrent readers while updating dev_opp */
• WARN_ON(!list_empty(&dev_opp->opp_list));
• regulator_put(dev_opp->regulator);
• dev_opp->regulator = ERR_PTR(-EINVAL);
• /* Try freeing device_opp if this was the last blocking resource */
• _remove_device_opp(dev_opp);

+unlock:

• mutex_unlock(&dev_opp_list_lock);

+} +EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulator);

I'm still lost why we need this API. When the OPP is torn down we can call regulator_put there instead. The same style seems to be done for supported hw, and prop_name, which doesn't make any sense either. Just tear everything down when there aren't any more OPPs in the table.