[PATCH 4.4.y-cip 07/23] PM / OPP: Add dev_pm_opp_set_rate()


Chen-Yu Tsai (Moxa) <wens@...>
 

From: Viresh Kumar <viresh.kumar@linaro.org>

commit 6a0712f6f199e737aa5913d28ec4bd3a25de9660 upstream.

This adds a routine, dev_pm_opp_set_rate(), responsible for configuring
power-supply and clock source for an OPP.

The OPP is found by matching against the target_freq passed to the
routine. This shall replace similar code present in most of the OPP
users and help simplify them a lot.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Chen-Yu Tsai (Moxa) <wens@csie.org>
---
drivers/base/power/opp/core.c | 176 ++++++++++++++++++++++++++++++++++
include/linux/pm_opp.h | 6 ++
2 files changed, 182 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.=
c
index 4fd3a59060e30..91b4cc261d84a 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -529,6 +529,182 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struc=
t device *dev,
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
=20
+/*
+ * The caller needs to ensure that device_opp (and hence the clk) isn't =
freed,
+ * while clk returned here is used.
+ */
+static struct clk *_get_opp_clk(struct device *dev)
+{
+ struct device_opp *dev_opp;
+ struct clk *clk;
+
+ rcu_read_lock();
+
+ dev_opp =3D _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+ clk =3D ERR_CAST(dev_opp);
+ goto unlock;
+ }
+
+ clk =3D dev_opp->clk;
+ if (IS_ERR(clk))
+ dev_err(dev, "%s: No clock available for the device\n",
+ __func__);
+
+unlock:
+ rcu_read_unlock();
+ return clk;
+}
+
+static int _set_opp_voltage(struct device *dev, struct regulator *reg,
+ unsigned long u_volt, unsigned long u_volt_min,
+ unsigned long u_volt_max)
+{
+ int ret;
+
+ /* Regulator not available for device */
+ if (IS_ERR(reg)) {
+ dev_dbg(dev, "%s: regulator not available: %ld\n", __func__,
+ PTR_ERR(reg));
+ return 0;
+ }
+
+ dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__, u_volt_min,
+ u_volt, u_volt_max);
+
+ ret =3D regulator_set_voltage_triplet(reg, u_volt_min, u_volt,
+ u_volt_max);
+ if (ret)
+ dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
+ __func__, u_volt_min, u_volt, u_volt_max, ret);
+
+ return ret;
+}
+
+/**
+ * dev_pm_opp_set_rate() - Configure new OPP based on frequency
+ * @dev: device for which we do this operation
+ * @target_freq: frequency to achieve
+ *
+ * This configures the power-supplies and clock source to the levels spe=
cified
+ * by the OPP corresponding to the target_freq.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
+{
+ struct device_opp *dev_opp;
+ struct dev_pm_opp *old_opp, *opp;
+ struct regulator *reg;
+ struct clk *clk;
+ unsigned long freq, old_freq;
+ unsigned long u_volt, u_volt_min, u_volt_max;
+ unsigned long ou_volt, ou_volt_min, ou_volt_max;
+ int ret;
+
+ if (unlikely(!target_freq)) {
+ dev_err(dev, "%s: Invalid target frequency %lu\n", __func__,
+ target_freq);
+ return -EINVAL;
+ }
+
+ clk =3D _get_opp_clk(dev);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ freq =3D clk_round_rate(clk, target_freq);
+ if ((long)freq <=3D 0)
+ freq =3D target_freq;
+
+ old_freq =3D clk_get_rate(clk);
+
+ /* Return early if nothing to do */
+ if (old_freq =3D=3D freq) {
+ dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do=
\n",
+ __func__, freq);
+ return 0;
+ }
+
+ rcu_read_lock();
+
+ dev_opp =3D _find_device_opp(dev);
+ if (IS_ERR(dev_opp)) {
+ dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+ rcu_read_unlock();
+ return PTR_ERR(dev_opp);
+ }
+
+ old_opp =3D dev_pm_opp_find_freq_ceil(dev, &old_freq);
+ if (!IS_ERR(old_opp)) {
+ ou_volt =3D old_opp->u_volt;
+ ou_volt_min =3D old_opp->u_volt_min;
+ ou_volt_max =3D old_opp->u_volt_max;
+ } else {
+ dev_err(dev, "%s: failed to find current OPP for freq %lu (%ld)\n",
+ __func__, old_freq, PTR_ERR(old_opp));
+ }
+
+ opp =3D dev_pm_opp_find_freq_ceil(dev, &freq);
+ if (IS_ERR(opp)) {
+ ret =3D PTR_ERR(opp);
+ dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
+ __func__, freq, ret);
+ rcu_read_unlock();
+ return ret;
+ }
+
+ u_volt =3D opp->u_volt;
+ u_volt_min =3D opp->u_volt_min;
+ u_volt_max =3D opp->u_volt_max;
+
+ reg =3D dev_opp->regulator;
+
+ rcu_read_unlock();
+
+ /* Scaling up? Scale voltage before frequency */
+ if (freq > old_freq) {
+ ret =3D _set_opp_voltage(dev, reg, u_volt, u_volt_min,
+ u_volt_max);
+ if (ret)
+ goto restore_voltage;
+ }
+
+ /* Change frequency */
+
+ dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n",
+ __func__, old_freq, freq);
+
+ ret =3D clk_set_rate(clk, freq);
+ if (ret) {
+ dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
+ ret);
+ goto restore_voltage;
+ }
+
+ /* Scaling down? Scale voltage after frequency */
+ if (freq < old_freq) {
+ ret =3D _set_opp_voltage(dev, reg, u_volt, u_volt_min,
+ u_volt_max);
+ if (ret)
+ goto restore_freq;
+ }
+
+ return 0;
+
+restore_freq:
+ if (clk_set_rate(clk, old_freq))
+ dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
+ __func__, old_freq);
+restore_voltage:
+ /* This shouldn't harm even if the voltages weren't updated earlier */
+ if (!IS_ERR(old_opp))
+ _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
+
/* List-dev Helpers */
static void _kfree_list_dev_rcu(struct rcu_head *head)
{
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 59da3d9e11ea3..cccaf4a29e9f0 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -64,6 +64,7 @@ int dev_pm_opp_set_prop_name(struct device *dev, const =
char *name);
void dev_pm_opp_put_prop_name(struct device *dev);
int dev_pm_opp_set_regulator(struct device *dev, const char *name);
void dev_pm_opp_put_regulator(struct device *dev);
+int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq);
#else
static inline unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *op=
p)
{
@@ -172,6 +173,11 @@ static inline int dev_pm_opp_set_regulator(struct de=
vice *dev, const char *name)
=20
static inline void dev_pm_opp_put_regulator(struct device *dev) {}
=20
+static inline int dev_pm_opp_set_rate(struct device *dev, unsigned long =
target_freq)
+{
+ return -EINVAL;
+}
+
#endif /* CONFIG_PM_OPP */
=20
#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
--=20
2.27.0

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