[PATCH v7 2/7] OPP: Add helpers for reading the binding properties

[Georgi Djakov <georgi.djakov@linaro.org>]

From: Saravana Kannan <saravanak@google.com>

The opp-hz DT property is not mandatory and we may use another property
as a key in the OPP table. Add helper functions to simplify the reading
and comparing the keys.

Signed-off-by: Saravana Kannan <saravanak@google.com>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---
v7:
* Extracted just the helpers from patch v6, as Viresh advised to split it.

v6: https://lore.kernel.org/r/20191207002424.201796-3-saravanak@google.com

 drivers/opp/core.c | 15 +++++++++++++--
 drivers/opp/of.c   | 42 ++++++++++++++++++++++++++----------------
 drivers/opp/opp.h  |  1 +
 3 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index ba43e6a3dc0a..c9c1bbe6ae27 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1272,11 +1272,21 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
 	return true;
 }
 
+int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
+{
+	if (opp1->rate != opp2->rate)
+		return opp1->rate < opp2->rate ? -1 : 1;
+	if (opp1->level != opp2->level)
+		return opp1->level < opp2->level ? -1 : 1;
+	return 0;
+}
+
 static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
 			     struct opp_table *opp_table,
 			     struct list_head **head)
 {
 	struct dev_pm_opp *opp;
+	int opp_cmp;
 
 	/*
 	 * Insert new OPP in order of increasing frequency and discard if
@@ -1287,12 +1297,13 @@ static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
 	 * loop.
 	 */
 	list_for_each_entry(opp, &opp_table->opp_list, node) {
-		if (new_opp->rate > opp->rate) {
+		opp_cmp = _opp_compare_key(new_opp, opp);
+		if (opp_cmp > 0) {
 			*head = &opp->node;
 			continue;
 		}
 
-		if (new_opp->rate < opp->rate)
+		if (opp_cmp < 0)
 			return 0;
 
 		/* Duplicate OPPs */
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 9cd8f0adacae..e33169c7e045 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -521,6 +521,28 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
+static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
+			 bool *rate_not_available)
+{
+	u64 rate;
+	int ret;
+
+	ret = of_property_read_u64(np, "opp-hz", &rate);
+	if (!ret) {
+		/*
+		 * Rate is defined as an unsigned long in clk API, and so
+		 * casting explicitly to its type. Must be fixed once rate is 64
+		 * bit guaranteed in clk API.
+		 */
+		new_opp->rate = (unsigned long)rate;
+	}
+	*rate_not_available = !!ret;
+
+	of_property_read_u32(np, "opp-level", &new_opp->level);
+
+	return ret;
+}
+
 /**
  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
  * @opp_table:	OPP table
@@ -558,26 +580,14 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	if (!new_opp)
 		return ERR_PTR(-ENOMEM);
 
-	ret = of_property_read_u64(np, "opp-hz", &rate);
+	ret = _read_opp_key(new_opp, np, &rate_not_available);
 	if (ret < 0) {
-		/* "opp-hz" is optional for devices like power domains. */
-		if (!opp_table->is_genpd) {
-			dev_err(dev, "%s: opp-hz not found\n", __func__);
-			goto free_opp;
-		}
+		if (!opp_table->is_genpd)
+			dev_err(dev, "%s: opp key field not found\n", __func__);
 
-		rate_not_available = true;
-	} else {
-		/*
-		 * Rate is defined as an unsigned long in clk API, and so
-		 * casting explicitly to its type. Must be fixed once rate is 64
-		 * bit guaranteed in clk API.
-		 */
-		new_opp->rate = (unsigned long)rate;
+		goto free_opp;
 	}
 
-	of_property_read_u32(np, "opp-level", &new_opp->level);
-
 	/* Check if the OPP supports hardware's hierarchy of versions or not */
 	if (!_opp_is_supported(dev, opp_table, np)) {
 		dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index d14e27102730..bcadb1e328a4 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -211,6 +211,7 @@ struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_
 void _dev_pm_opp_find_and_remove_table(struct device *dev);
 struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
 void _opp_free(struct dev_pm_opp *opp);
+int _opp_compare_key(struct dev_pm_opp *opp1, struct dev_pm_opp *opp2);
 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table, bool rate_not_available);
 int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, int last_cpu);