From a88bd2a51e901ed8081841d647157de8153df813 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 29 Nov 2017 15:18:36 +0530 Subject: PM / OPP: Implement of_dev_pm_opp_find_required_opp() 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 Reviewed-by: Ulf Hansson --- drivers/opp/of.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) (limited to 'drivers/opp/of.c') diff --git a/drivers/opp/of.c b/drivers/opp/of.c index cba669cd00c5..6380ec3d695b 100644 --- a/drivers/opp/of.c +++ b/drivers/opp/of.c @@ -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); -- cgit v1.2.3-59-g8ed1b