PM / devfreq: exynos-bus: Convert to use dev_pm_opp_set_rate()

Reuse opp core code for setting bus clock and voltage. As a side
effect this allow usage 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). After applying changes both functions exynos_bus_passive_target()
and exynos_bus_target() have the same code, so remove
exynos_bus_passive_target(). In exynos_bus_probe() replace it with
exynos_bus_target.
Signed-off-by: Kamil Konieczny <k.konieczny@partner.samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/exynos-bus.c

@@ -22,7 +22,6 @@
 #include <linux/slab.h>
 
 #define DEFAULT_SATURATION_RATIO	40
-#define DEFAULT_VOLTAGE_TOLERANCE	2
 
 struct exynos_bus {
 	struct device *dev;
@@ -34,9 +33,8 @@ 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;
 };
 
@@ -90,62 +88,29 @@ static int exynos_bus_get_event(struct exynos_bus *bus,
 }
 
 /*
- * Must necessary function for devfreq simple-ondemand governor
+ * devfreq function for both simple-ondemand and passive governor
  */
 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 */
+	/* Get correct frequency for bus. */
 	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;
@@ -193,54 +158,10 @@ static void exynos_bus_exit(struct device *dev)
 
 	dev_pm_opp_of_remove_table(dev);
 	clk_disable_unprepare(bus->clk);
-	if (bus->regulator)
-		regulator_disable(bus->regulator);
-}
-
-/*
- * Must necessary function for devfreq passive governor
- */
-static int exynos_bus_passive_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;
-	int ret = 0;
-
-	/* Get new opp-bus instance according to new bus clock */
-	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 = clk_set_rate(bus->clk, new_freq);
-	if (ret < 0) {
-		dev_err(dev, "failed to set the clock of bus\n");
-		goto out;
+	if (bus->opp_table) {
+		dev_pm_opp_put_regulators(bus->opp_table);
+		bus->opp_table = NULL;
 	}
-
-	*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;
 }
 
 static void exynos_bus_passive_exit(struct device *dev)
@@ -255,21 +176,19 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
 					struct exynos_bus *bus)
 {
 	struct device *dev = bus->dev;
+	struct opp_table *opp_table;
+	const char *vdd = "vdd";
 	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");
+	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);
 		return ret;
 	}
 
+	bus->opp_table = opp_table;
+
 	/*
 	 * Get the devfreq-event devices to get the current utilization of
 	 * buses. This raw data will be used in devfreq ondemand governor.
@@ -310,14 +229,11 @@ 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);
+	dev_pm_opp_put_regulators(bus->opp_table);
+	bus->opp_table = NULL;
 
 	return ret;
 }
@@ -468,7 +384,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	goto out;
 passive:
 	/* Initialize the struct profile and governor data for passive device */
-	profile->target = exynos_bus_passive_target;
+	profile->target = exynos_bus_target;
 	profile->exit = exynos_bus_passive_exit;
 
 	/* Get the instance of parent devfreq device */
@@ -508,8 +424,10 @@ static int exynos_bus_probe(struct platform_device *pdev)
 	dev_pm_opp_of_remove_table(dev);
 	clk_disable_unprepare(bus->clk);
 err_reg:
-	if (!passive)
-		regulator_disable(bus->regulator);
+	if (!passive) {
+		dev_pm_opp_put_regulators(bus->opp_table);
+		bus->opp_table = NULL;
+	}
 
 	return ret;
 }