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PM / OPP: Implement of_dev_pm_opp_find_required_opp()

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A device's DT node or its OPP nodes can contain a phandle to other
device's OPP node, in the "required-opps" property.

This patch implements a routine to find that required OPP from the node
that contains the "required-opps" property.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Viresh Kumar
2017-11-29 15:18:36 +05:30
parent fa9b274f8a
commit a88bd2a51e
4 changed files with 62 additions and 3 deletions
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54
drivers/opp/of.c
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@@ -673,3 +673,57 @@ put_cpu_node:
return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
/**
* of_dev_pm_opp_find_required_opp() - Search for required OPP.
* @dev: The device whose OPP node is referenced by the 'np' DT node.
* @np: Node that contains the "required-opps" property.
*
* Returns the OPP of the device 'dev', whose phandle is present in the "np"
* node. Although the "required-opps" property supports having multiple
* phandles, this helper routine only parses the very first phandle in the list.
*
* Return: Matching opp, else returns ERR_PTR in case of error and should be
* handled using IS_ERR.
*
* The callers are required to call dev_pm_opp_put() for the returned OPP after
* use.
*/
struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
struct device_node *np)
{
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
struct device_node *required_np;
struct opp_table *opp_table;
opp_table = _find_opp_table(dev);
if (IS_ERR(opp_table))
return ERR_CAST(opp_table);
required_np = of_parse_phandle(np, "required-opps", 0);
if (unlikely(!required_np)) {
dev_err(dev, "Unable to parse required-opps\n");
goto put_opp_table;
}
mutex_lock(&opp_table->lock);
list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
if (temp_opp->available && temp_opp->np == required_np) {
opp = temp_opp;
/* Increment the reference count of OPP */
dev_pm_opp_get(opp);
break;
}
}
mutex_unlock(&opp_table->lock);
of_node_put(required_np);
put_opp_table:
dev_pm_opp_put_opp_table(opp_table);
return opp;
}
EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);