[PATCH v2 2/4] devfreq: exynos-bus: convert to use dev_pm_opp_set_rate()

[Kamil Konieczny]

Reuse opp core code for setting bus clock and voltage. As a side
effect this allow useage of coupled regulators feature (required
for boards using Exynos5422/5800 SoCs) because dev_pm_opp_set_rate()
uses regulator_set_voltage_triplet() for setting regulator voltage
while the old code used regulator_set_voltage_tol() with fixed
tolerance. This patch also removes no longer needed parsing of DT
property "exynos,voltage-tolerance" (no Exynos devfreq DT node uses
it).

Signed-off-by: Kamil Konieczny <k.konieczny@xxxxxxxxxxxxxxxxxxx>
---
 drivers/devfreq/exynos-bus.c | 172 ++++++++++++++---------------------
 1 file changed, 66 insertions(+), 106 deletions(-)

diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
index 486cc5b422f1..7fc4f76bd848 100644
--- a/drivers/devfreq/exynos-bus.c
+++ b/drivers/devfreq/exynos-bus.c
@@ -25,7 +25,6 @@
 #include <linux/slab.h>
 
 #define DEFAULT_SATURATION_RATIO	40
-#define DEFAULT_VOLTAGE_TOLERANCE	2
 
 struct exynos_bus {
 	struct device *dev;
@@ -37,9 +36,9 @@ struct exynos_bus {
 
 	unsigned long curr_freq;
 
-	struct regulator *regulator;
+	struct opp_table *opp_table;
+
 	struct clk *clk;
-	unsigned int voltage_tolerance;
 	unsigned int ratio;
 };
 
@@ -99,56 +98,25 @@ static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
 {
 	struct exynos_bus *bus = dev_get_drvdata(dev);
 	struct dev_pm_opp *new_opp;
-	unsigned long old_freq, new_freq, new_volt, tol;
 	int ret = 0;
-
-	/* Get new opp-bus instance according to new bus clock */
+	/*
+	 * New frequency for bus may not be exactly matched to opp, adjust
+	 * *freq to correct value.
+	 */
 	new_opp = devfreq_recommended_opp(dev, freq, flags);
 	if (IS_ERR(new_opp)) {
 		dev_err(dev, "failed to get recommended opp instance\n");
 		return PTR_ERR(new_opp);
 	}
 
-	new_freq = dev_pm_opp_get_freq(new_opp);
-	new_volt = dev_pm_opp_get_voltage(new_opp);
 	dev_pm_opp_put(new_opp);
 
-	old_freq = bus->curr_freq;
-
-	if (old_freq == new_freq)
-		return 0;
-	tol = new_volt * bus->voltage_tolerance / 100;
-
 	/* Change voltage and frequency according to new OPP level */
 	mutex_lock(&bus->lock);
+	ret = dev_pm_opp_set_rate(dev, *freq);
+	if (!ret)
+		bus->curr_freq = *freq;
 
-	if (old_freq < new_freq) {
-		ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
-		if (ret < 0) {
-			dev_err(bus->dev, "failed to set voltage\n");
-			goto out;
-		}
-	}
-
-	ret = clk_set_rate(bus->clk, new_freq);
-	if (ret < 0) {
-		dev_err(dev, "failed to change clock of bus\n");
-		clk_set_rate(bus->clk, old_freq);
-		goto out;
-	}
-
-	if (old_freq > new_freq) {
-		ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
-		if (ret < 0) {
-			dev_err(bus->dev, "failed to set voltage\n");
-			goto out;
-		}
-	}
-	bus->curr_freq = new_freq;
-
-	dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
-			old_freq, new_freq, clk_get_rate(bus->clk));
-out:
 	mutex_unlock(&bus->lock);
 
 	return ret;
@@ -194,10 +162,11 @@ static void exynos_bus_exit(struct device *dev)
 	if (ret < 0)
 		dev_warn(dev, "failed to disable the devfreq-event devices\n");
 
-	if (bus->regulator)
-		regulator_disable(bus->regulator);
+	if (bus->opp_table)
+		dev_pm_opp_put_regulators(bus->opp_table);
 
 	dev_pm_opp_of_remove_table(dev);
+
 	clk_disable_unprepare(bus->clk);
 }
 
@@ -209,39 +178,26 @@ static int exynos_bus_passive_target(struct device *dev, unsigned long *freq,
 {
 	struct exynos_bus *bus = dev_get_drvdata(dev);
 	struct dev_pm_opp *new_opp;
-	unsigned long old_freq, new_freq;
-	int ret = 0;
+	int ret;
 
-	/* Get new opp-bus instance according to new bus clock */
+	/*
+	 * New frequency for bus may not be exactly matched to opp, adjust
+	 * *freq to correct value.
+	 */
 	new_opp = devfreq_recommended_opp(dev, freq, flags);
 	if (IS_ERR(new_opp)) {
 		dev_err(dev, "failed to get recommended opp instance\n");
 		return PTR_ERR(new_opp);
 	}
 
-	new_freq = dev_pm_opp_get_freq(new_opp);
 	dev_pm_opp_put(new_opp);
 
-	old_freq = bus->curr_freq;
-
-	if (old_freq == new_freq)
-		return 0;
-
 	/* Change the frequency according to new OPP level */
 	mutex_lock(&bus->lock);
+	ret = dev_pm_opp_set_rate(dev, *freq);
+	if (!ret)
+		bus->curr_freq = *freq;
 
-	ret = clk_set_rate(bus->clk, new_freq);
-	if (ret < 0) {
-		dev_err(dev, "failed to set the clock of bus\n");
-		goto out;
-	}
-
-	*freq = new_freq;
-	bus->curr_freq = new_freq;
-
-	dev_dbg(dev, "Set the frequency of bus (%luHz -> %luHz, %luHz)\n",
-			old_freq, new_freq, clk_get_rate(bus->clk));
-out:
 	mutex_unlock(&bus->lock);
 
 	return ret;
@@ -259,20 +215,7 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
 					struct exynos_bus *bus)
 {
 	struct device *dev = bus->dev;
-	int i, ret, count, size;
-
-	/* Get the regulator to provide each bus with the power */
-	bus->regulator = devm_regulator_get(dev, "vdd");
-	if (IS_ERR(bus->regulator)) {
-		dev_err(dev, "failed to get VDD regulator\n");
-		return PTR_ERR(bus->regulator);
-	}
-
-	ret = regulator_enable(bus->regulator);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable VDD regulator\n");
-		return ret;
-	}
+	int i, count, size;
 
 	/*
 	 * Get the devfreq-event devices to get the current utilization of
@@ -281,24 +224,20 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
 	count = devfreq_event_get_edev_count(dev);
 	if (count < 0) {
 		dev_err(dev, "failed to get the count of devfreq-event dev\n");
-		ret = count;
-		goto err_regulator;
+		return count;
 	}
+
 	bus->edev_count = count;
 
 	size = sizeof(*bus->edev) * count;
 	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
-	if (!bus->edev) {
-		ret = -ENOMEM;
-		goto err_regulator;
-	}
+	if (!bus->edev)
+		return -ENOMEM;
 
 	for (i = 0; i < count; i++) {
 		bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
-		if (IS_ERR(bus->edev[i])) {
-			ret = -EPROBE_DEFER;
-			goto err_regulator;
-		}
+		if (IS_ERR(bus->edev[i]))
+			return -EPROBE_DEFER;
 	}
 
 	/*
@@ -314,22 +253,15 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
 	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
 		bus->ratio = DEFAULT_SATURATION_RATIO;
 
-	if (of_property_read_u32(np, "exynos,voltage-tolerance",
-					&bus->voltage_tolerance))
-		bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;
-
 	return 0;
-
-err_regulator:
-	regulator_disable(bus->regulator);
-
-	return ret;
 }
 
 static int exynos_bus_parse_of(struct device_node *np,
-			      struct exynos_bus *bus)
+			      struct exynos_bus *bus, bool passive)
 {
 	struct device *dev = bus->dev;
+	struct opp_table *opp_table;
+	const char *vdd = "vdd";
 	struct dev_pm_opp *opp;
 	unsigned long rate;
 	int ret;
@@ -347,11 +279,22 @@ static int exynos_bus_parse_of(struct device_node *np,
 		return ret;
 	}
 
+	if (!passive) {
+		opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
+		if (IS_ERR(opp_table)) {
+			ret = PTR_ERR(opp_table);
+			dev_err(dev, "failed to set regulators %d\n", ret);
+			goto err_clk;
+		}
+
+		bus->opp_table = opp_table;
+	}
+
 	/* Get the freq and voltage from OPP table to scale the bus freq */
 	ret = dev_pm_opp_of_add_table(dev);
 	if (ret < 0) {
 		dev_err(dev, "failed to get OPP table\n");
-		goto err_clk;
+		goto err_regulator;
 	}
 
 	rate = clk_get_rate(bus->clk);
@@ -362,6 +305,7 @@ static int exynos_bus_parse_of(struct device_node *np,
 		ret = PTR_ERR(opp);
 		goto err_opp;
 	}
+
 	bus->curr_freq = dev_pm_opp_get_freq(opp);
 	dev_pm_opp_put(opp);
 
@@ -369,6 +313,13 @@ static int exynos_bus_parse_of(struct device_node *np,
 
 err_opp:
 	dev_pm_opp_of_remove_table(dev);
+
+err_regulator:
+	if (bus->opp_table) {
+		dev_pm_opp_put_regulators(bus->opp_table);
+		bus->opp_table = NULL;
+	}
+
 err_clk:
 	clk_disable_unprepare(bus->clk);
 
@@ -386,6 +337,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	struct exynos_bus *bus;
 	int ret, max_state;
 	unsigned long min_freq, max_freq;
+	bool passive = false;
 
 	if (!np) {
 		dev_err(dev, "failed to find devicetree node\n");
@@ -395,12 +347,18 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
 	if (!bus)
 		return -ENOMEM;
+
 	mutex_init(&bus->lock);
 	bus->dev = &pdev->dev;
 	platform_set_drvdata(pdev, bus);
+	node = of_parse_phandle(dev->of_node, "devfreq", 0);
+	if (node) {
+		of_node_put(node);
+		passive = true;
+	}
 
 	/* Parse the device-tree to get the resource information */
-	ret = exynos_bus_parse_of(np, bus);
+	ret = exynos_bus_parse_of(np, bus, passive);
 	if (ret < 0)
 		return ret;
 
@@ -410,13 +368,10 @@ static int exynos_bus_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	node = of_parse_phandle(dev->of_node, "devfreq", 0);
-	if (node) {
-		of_node_put(node);
+	if (passive)
 		goto passive;
-	} else {
-		ret = exynos_bus_parent_parse_of(np, bus);
-	}
+
+	ret = exynos_bus_parent_parse_of(np, bus);
 
 	if (ret < 0)
 		goto err;
@@ -509,6 +464,11 @@ static int exynos_bus_probe(struct platform_device *pdev)
 
 err:
 	dev_pm_opp_of_remove_table(dev);
+	if (bus->opp_table) {
+		dev_pm_opp_put_regulators(bus->opp_table);
+		bus->opp_table = NULL;
+	}
+
 	clk_disable_unprepare(bus->clk);
 
 	return ret;
-- 
2.22.0