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

Kamil Konieczny
2019-07-15T12:05:40Z

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@partner.samsung.com>
---
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