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[PATCH V5 00/10] PM / OPP: Multiple regulator support

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  [PATCH V5 00/10] PM / OPP: Multiple regulator support Viresh Kumar <viresh.kumar@linaro.org> - 2016-11-29 07:40 +0100
    [PATCH V5 06/10] PM / OPP: Add infrastructure to manage multiple regulators Viresh Kumar <viresh.kumar@linaro.org> - 2016-11-29 07:40 +0100
    [PATCH V5 02/10] PM / OPP: Reword binding supporting multiple regulators per device Viresh Kumar <viresh.kumar@linaro.org> - 2016-11-29 07:40 +0100
    [PATCH V5 03/10] PM / OPP: Don't use OPP structure outside of rcu protected section Viresh Kumar <viresh.kumar@linaro.org> - 2016-11-29 07:50 +0100
    Re: [PATCH V5 00/10] PM / OPP: Multiple regulator support "Rafael J. Wysocki" <rafael@kernel.org> - 2016-11-29 13:50 +0100

#1531931 — [PATCH V5 00/10] PM / OPP: Multiple regulator support

Hi,

Some platforms (like TI) have complex DVFS configuration for CPU
devices, where multiple regulators are required to be configured to
change DVFS state of the device. This was explained well by Nishanth
earlier [1].

One of the major complaints around multiple regulators case was that the
DT isn't responsible in any way to represent the order in which multiple
supplies need to be programmed, before or after a frequency change. It
was considered in this patch and such information is left for the
platform specific OPP driver now, which can register its own
opp_set_rate() callback with the OPP core and the OPP core will then
call it during DVFS.

The patches are tested on Exynos5250 (Dual A15). I have hacked around DT
and code to pass values for multiple regulators and verified that they
are all properly read by the kernel (using debugfs interface).

Dave Gerlach has already tested [2] it on the real TI platforms and it
works well for him.

This is rebased over: linux-next branch in the PM tree.

V4->V5:
- Stephen boyd had some minor review comments and gave his Reviewed-by
  tag for the rest. Only 2 patches don't have his RBY tag.
- Individual patches contain the version history from V4 to V5.

V3->V4:
- Separate out cpu-supply fix in the binding in a separate patch (Mark).
- Add more documentation to the binding to explain that the relation to
  the supplies and the order of programming them is left for the
  platform specific bindings and that every platform using multiple
  regulators for their devices needs to provide a separate binding
  document explaining their implementation (Mark).
- @Rob and Stephen: I have kept your Acks for the bindings as the
  bindings only got a bit reworded (improved) since the time you guys
  Acked them. Please let me know if you want more improvement in the
  bindings now.
- V4 for 10/10 was sent earlier, which added a missing
  rcu_read_unlock(). Nothing else changed in it.
- Added some missing Kernel documentation comments

V2->V3:
- The last patch is new
- Removed a debug leftover pr_info() message
- Renamed few names as s/set_rate/set_opp
- Removed a TODO comment (as it is done now with this series)
- created struct for min_uV and max_uV
- kerneldoc comments for structures in pm_opp.h
- s/const char */const char * const
- use kasprintf()
- Some more minor reformatting
- More Ack/RBY tags added

V1->V2:
- Ack from Rob for 1st patch
- Moved the supplies structure to pm_opp.h (Dave)
- Fixed an compilation warning.

--
viresh

[1] https://marc.info/?l=linux-pm&m=145684495832764&w=2
[2] https://marc.info/?l=linux-kernel&m=147924789305276&w=2

Viresh Kumar (10):
  PM / OPP: Fix incorrect cpu-supply property in binding
  PM / OPP: Reword binding supporting multiple regulators per device
  PM / OPP: Don't use OPP structure outside of rcu protected section
  PM / OPP: Manage supply's voltage/current in a separate structure
  PM / OPP: Pass struct dev_pm_opp_supply to _set_opp_voltage()
  PM / OPP: Add infrastructure to manage multiple regulators
  PM / OPP: Separate out _generic_set_opp()
  PM / OPP: Allow platform specific custom set_opp() callbacks
  PM / OPP: Don't WARN on multiple calls to dev_pm_opp_set_regulators()
  PM / OPP: Don't assume platform doesn't have regulators

 Documentation/devicetree/bindings/opp/opp.txt |  27 +-
 drivers/base/power/opp/core.c                 | 536 ++++++++++++++++++++------
 drivers/base/power/opp/debugfs.c              |  52 ++-
 drivers/base/power/opp/of.c                   | 105 +++--
 drivers/base/power/opp/opp.h                  |  22 +-
 drivers/cpufreq/cpufreq-dt.c                  |   9 +-
 include/linux/pm_opp.h                        |  69 +++-
 7 files changed, 634 insertions(+), 186 deletions(-)

-- 
2.7.1.410.g6faf27b

[toc] | [next] | [standalone]

#1531932 — [PATCH V5 06/10] PM / OPP: Add infrastructure to manage multiple regulators

This patch adds infrastructure to manage multiple regulators and updates
the only user (cpufreq-dt) of dev_pm_opp_set{put}_regulator().

This is preparatory work for adding full support for devices with
multiple regulators.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>

---
V4->V5:
- Don't allocate from within rcu locked section.
- s/+//
---
 drivers/base/power/opp/core.c    | 246 +++++++++++++++++++++++++++------------
 drivers/base/power/opp/debugfs.c |  52 +++++++--
 drivers/base/power/opp/of.c      | 103 +++++++++++-----
 drivers/base/power/opp/opp.h     |  10 +-
 drivers/cpufreq/cpufreq-dt.c     |   9 +-
 include/linux/pm_opp.h           |   8 +-
 6 files changed, 301 insertions(+), 127 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 37fad2eb0f47..89a3fd720724 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -93,6 +93,8 @@ struct opp_table *_find_opp_table(struct device *dev)
  * Return: voltage in micro volt corresponding to the opp, else
  * return 0
  *
+ * This is useful only for devices with single power supply.
+ *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu
  * protected pointer. This means that opp which could have been fetched by
  * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
@@ -112,7 +114,7 @@ unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
 	if (IS_ERR_OR_NULL(tmp_opp))
 		pr_err("%s: Invalid parameters\n", __func__);
 	else
-		v = tmp_opp->supply.u_volt;
+		v = tmp_opp->supplies[0].u_volt;
 
 	return v;
 }
@@ -210,6 +212,24 @@ unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
 
+static int _get_regulator_count(struct device *dev)
+{
+	struct opp_table *opp_table;
+	int count;
+
+	rcu_read_lock();
+
+	opp_table = _find_opp_table(dev);
+	if (!IS_ERR(opp_table))
+		count = opp_table->regulator_count;
+	else
+		count = 0;
+
+	rcu_read_unlock();
+
+	return count;
+}
+
 /**
  * dev_pm_opp_get_max_volt_latency() - Get max voltage latency in nanoseconds
  * @dev: device for which we do this operation
@@ -222,34 +242,51 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 {
 	struct opp_table *opp_table;
 	struct dev_pm_opp *opp;
-	struct regulator *reg;
+	struct regulator *reg, **regulators;
 	unsigned long latency_ns = 0;
-	unsigned long min_uV = ~0, max_uV = 0;
-	int ret;
+	int ret, i, count;
+	struct {
+		unsigned long min;
+		unsigned long max;
+	} *uV;
+
+	count = _get_regulator_count(dev);
+
+	/* Regulator may not be required for the device */
+	if (!count)
+		return 0;
+
+	regulators = kmalloc_array(count, sizeof(*regulators), GFP_KERNEL);
+	if (!regulators)
+		return 0;
+
+	uV = kmalloc_array(count, sizeof(*uV), GFP_KERNEL);
+	if (!uV)
+		goto free_regulators;
 
 	rcu_read_lock();
 
 	opp_table = _find_opp_table(dev);
 	if (IS_ERR(opp_table)) {
 		rcu_read_unlock();
-		return 0;
+		goto free_uV;
 	}
 
-	reg = opp_table->regulator;
-	if (IS_ERR(reg)) {
-		/* Regulator may not be required for device */
-		rcu_read_unlock();
-		return 0;
-	}
+	memcpy(regulators, opp_table->regulators, count * sizeof(*regulators));
 
-	list_for_each_entry_rcu(opp, &opp_table->opp_list, node) {
-		if (!opp->available)
-			continue;
+	for (i = 0; i < count; i++) {
+		uV[i].min = ~0;
+		uV[i].max = 0;
 
-		if (opp->supply.u_volt_min < min_uV)
-			min_uV = opp->supply.u_volt_min;
-		if (opp->supply.u_volt_max > max_uV)
-			max_uV = opp->supply.u_volt_max;
+		list_for_each_entry_rcu(opp, &opp_table->opp_list, node) {
+			if (!opp->available)
+				continue;
+
+			if (opp->supplies[i].u_volt_min < uV[i].min)
+				uV[i].min = opp->supplies[i].u_volt_min;
+			if (opp->supplies[i].u_volt_max > uV[i].max)
+				uV[i].max = opp->supplies[i].u_volt_max;
+		}
 	}
 
 	rcu_read_unlock();
@@ -258,9 +295,16 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 	 * The caller needs to ensure that opp_table (and hence the regulator)
 	 * isn't freed, while we are executing this routine.
 	 */
-	ret = regulator_set_voltage_time(reg, min_uV, max_uV);
-	if (ret > 0)
-		latency_ns = ret * 1000;
+	for (i = 0; reg = regulators[i], i < count; i++) {
+		ret = regulator_set_voltage_time(reg, uV[i].min, uV[i].max);
+		if (ret > 0)
+			latency_ns += ret * 1000;
+	}
+
+free_uV:
+	kfree(uV);
+free_regulators:
+	kfree(regulators);
 
 	return latency_ns;
 }
@@ -580,7 +624,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 {
 	struct opp_table *opp_table;
 	struct dev_pm_opp *old_opp, *opp;
-	struct regulator *reg;
+	struct regulator *reg = ERR_PTR(-ENXIO);
 	struct clk *clk;
 	unsigned long freq, old_freq;
 	struct dev_pm_opp_supply old_supply, new_supply;
@@ -633,14 +677,23 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 		return ret;
 	}
 
+	if (opp_table->regulators) {
+		/* This function only supports single regulator per device */
+		if (WARN_ON(opp_table->regulator_count > 1)) {
+			dev_err(dev, "multiple regulators not supported\n");
+			rcu_read_unlock();
+			return -EINVAL;
+		}
+
+		reg = opp_table->regulators[0];
+	}
+
 	if (IS_ERR(old_opp))
 		old_supply.u_volt = 0;
 	else
-		memcpy(&old_supply, &old_opp->supply, sizeof(old_supply));
-
-	memcpy(&new_supply, &opp->supply, sizeof(new_supply));
+		memcpy(&old_supply, old_opp->supplies, sizeof(old_supply));
 
-	reg = opp_table->regulator;
+	memcpy(&new_supply, opp->supplies, sizeof(new_supply));
 
 	rcu_read_unlock();
 
@@ -764,9 +817,6 @@ static struct opp_table *_add_opp_table(struct device *dev)
 
 	_of_init_opp_table(opp_table, dev);
 
-	/* Set regulator to a non-NULL error value */
-	opp_table->regulator = ERR_PTR(-ENXIO);
-
 	/* Find clk for the device */
 	opp_table->clk = clk_get(dev, NULL);
 	if (IS_ERR(opp_table->clk)) {
@@ -815,7 +865,7 @@ static void _remove_opp_table(struct opp_table *opp_table)
 	if (opp_table->prop_name)
 		return;
 
-	if (!IS_ERR(opp_table->regulator))
+	if (opp_table->regulators)
 		return;
 
 	/* Release clk */
@@ -924,35 +974,50 @@ struct dev_pm_opp *_allocate_opp(struct device *dev,
 				 struct opp_table **opp_table)
 {
 	struct dev_pm_opp *opp;
+	int count, supply_size;
+	struct opp_table *table;
 
-	/* allocate new OPP node */
-	opp = kzalloc(sizeof(*opp), GFP_KERNEL);
-	if (!opp)
+	table = _add_opp_table(dev);
+	if (!table)
 		return NULL;
 
-	INIT_LIST_HEAD(&opp->node);
+	/* Allocate space for at least one supply */
+	count = table->regulator_count ? table->regulator_count : 1;
+	supply_size = sizeof(*opp->supplies) * count;
 
-	*opp_table = _add_opp_table(dev);
-	if (!*opp_table) {
-		kfree(opp);
+	/* allocate new OPP node and supplies structures */
+	opp = kzalloc(sizeof(*opp) + supply_size, GFP_KERNEL);
+	if (!opp) {
+		kfree(table);
 		return NULL;
 	}
 
+	/* Put the supplies at the end of the OPP structure as an empty array */
+	opp->supplies = (struct dev_pm_opp_supply *)(opp + 1);
+	INIT_LIST_HEAD(&opp->node);
+
+	*opp_table = table;
+
 	return opp;
 }
 
 static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
 					 struct opp_table *opp_table)
 {
-	struct regulator *reg = opp_table->regulator;
-
-	if (!IS_ERR(reg) &&
-	    !regulator_is_supported_voltage(reg, opp->supply.u_volt_min,
-					    opp->supply.u_volt_max)) {
-		pr_warn("%s: OPP minuV: %lu maxuV: %lu, not supported by regulator\n",
-			__func__, opp->supply.u_volt_min,
-			opp->supply.u_volt_max);
-		return false;
+	struct regulator *reg;
+	int i;
+
+	for (i = 0; i < opp_table->regulator_count; i++) {
+		reg = opp_table->regulators[i];
+
+		if (!regulator_is_supported_voltage(reg,
+					opp->supplies[i].u_volt_min,
+					opp->supplies[i].u_volt_max)) {
+			pr_warn("%s: OPP minuV: %lu maxuV: %lu, not supported by regulator\n",
+				__func__, opp->supplies[i].u_volt_min,
+				opp->supplies[i].u_volt_max);
+			return false;
+		}
 	}
 
 	return true;
@@ -984,12 +1049,13 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
 
 		/* Duplicate OPPs */
 		dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
-			 __func__, opp->rate, opp->supply.u_volt,
-			 opp->available, new_opp->rate, new_opp->supply.u_volt,
-			 new_opp->available);
+			 __func__, opp->rate, opp->supplies[0].u_volt,
+			 opp->available, new_opp->rate,
+			 new_opp->supplies[0].u_volt, new_opp->available);
 
+		/* Should we compare voltages for all regulators here ? */
 		return opp->available &&
-		       new_opp->supply.u_volt == opp->supply.u_volt ? 0 : -EEXIST;
+		       new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? 0 : -EEXIST;
 	}
 
 	new_opp->opp_table = opp_table;
@@ -1056,9 +1122,9 @@ int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
 	/* populate the opp table */
 	new_opp->rate = freq;
 	tol = u_volt * opp_table->voltage_tolerance_v1 / 100;
-	new_opp->supply.u_volt = u_volt;
-	new_opp->supply.u_volt_min = u_volt - tol;
-	new_opp->supply.u_volt_max = u_volt + tol;
+	new_opp->supplies[0].u_volt = u_volt;
+	new_opp->supplies[0].u_volt_min = u_volt - tol;
+	new_opp->supplies[0].u_volt_max = u_volt + tol;
 	new_opp->available = true;
 	new_opp->dynamic = dynamic;
 
@@ -1303,12 +1369,14 @@ void dev_pm_opp_put_prop_name(struct device *dev)
 EXPORT_SYMBOL_GPL(dev_pm_opp_put_prop_name);
 
 /**
- * dev_pm_opp_set_regulator() - Set regulator name for the device
+ * dev_pm_opp_set_regulators() - Set regulator names for the device
  * @dev: Device for which regulator name is being set.
- * @name: Name of the regulator.
+ * @names: Array of pointers to the names of the regulator.
+ * @count: Number of regulators.
  *
  * In order to support OPP switching, OPP layer needs to know the name of the
- * device's regulator, as the core would be required to switch voltages as well.
+ * device's regulators, as the core would be required to switch voltages as
+ * well.
  *
  * This must be called before any OPPs are initialized for the device.
  *
@@ -1318,11 +1386,12 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_put_prop_name);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex cannot be locked.
  */
-int dev_pm_opp_set_regulator(struct device *dev, const char *name)
+int dev_pm_opp_set_regulators(struct device *dev, const char * const names[],
+			      unsigned int count)
 {
 	struct opp_table *opp_table;
 	struct regulator *reg;
-	int ret;
+	int ret, i;
 
 	mutex_lock(&opp_table_lock);
 
@@ -1338,26 +1407,44 @@ int dev_pm_opp_set_regulator(struct device *dev, const char *name)
 		goto err;
 	}
 
-	/* Already have a regulator set */
-	if (WARN_ON(!IS_ERR(opp_table->regulator))) {
+	/* Already have regulators set */
+	if (WARN_ON(opp_table->regulators)) {
 		ret = -EBUSY;
 		goto err;
 	}
-	/* Allocate the regulator */
-	reg = regulator_get_optional(dev, name);
-	if (IS_ERR(reg)) {
-		ret = PTR_ERR(reg);
-		if (ret != -EPROBE_DEFER)
-			dev_err(dev, "%s: no regulator (%s) found: %d\n",
-				__func__, name, ret);
+
+	opp_table->regulators = kmalloc_array(count,
+					      sizeof(*opp_table->regulators),
+					      GFP_KERNEL);
+	if (!opp_table->regulators) {
+		ret = -ENOMEM;
 		goto err;
 	}
 
-	opp_table->regulator = reg;
+	for (i = 0; i < count; i++) {
+		reg = regulator_get_optional(dev, names[i]);
+		if (IS_ERR(reg)) {
+			ret = PTR_ERR(reg);
+			if (ret != -EPROBE_DEFER)
+				dev_err(dev, "%s: regulator (%s) not found: %d\n",
+					__func__, names[i], ret);
+			goto free_regulators;
+		}
+
+		opp_table->regulators[i] = reg;
+	}
+
+	opp_table->regulator_count = count;
 
 	mutex_unlock(&opp_table_lock);
 	return 0;
 
+free_regulators:
+	while (i != 0)
+		regulator_put(opp_table->regulators[--i]);
+
+	kfree(opp_table->regulators);
+	opp_table->regulators = NULL;
 err:
 	_remove_opp_table(opp_table);
 unlock:
@@ -1365,11 +1452,11 @@ int dev_pm_opp_set_regulator(struct device *dev, const char *name)
 
 	return ret;
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulator);
+EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulators);
 
 /**
- * dev_pm_opp_put_regulator() - Releases resources blocked for regulator
- * @dev: Device for which regulator was set.
+ * dev_pm_opp_put_regulators() - Releases resources blocked for regulators
+ * @dev: Device for which regulators were set.
  *
  * Locking: The internal opp_table and opp structures are RCU protected.
  * Hence this function internally uses RCU updater strategy with mutex locks
@@ -1377,9 +1464,10 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulator);
  * that this function is *NOT* called under RCU protection or in contexts where
  * mutex cannot be locked.
  */
-void dev_pm_opp_put_regulator(struct device *dev)
+void dev_pm_opp_put_regulators(struct device *dev)
 {
 	struct opp_table *opp_table;
+	int i;
 
 	mutex_lock(&opp_table_lock);
 
@@ -1391,16 +1479,20 @@ void dev_pm_opp_put_regulator(struct device *dev)
 		goto unlock;
 	}
 
-	if (IS_ERR(opp_table->regulator)) {
-		dev_err(dev, "%s: Doesn't have regulator set\n", __func__);
+	if (!opp_table->regulators) {
+		dev_err(dev, "%s: Doesn't have regulators set\n", __func__);
 		goto unlock;
 	}
 
 	/* Make sure there are no concurrent readers while updating opp_table */
 	WARN_ON(!list_empty(&opp_table->opp_list));
 
-	regulator_put(opp_table->regulator);
-	opp_table->regulator = ERR_PTR(-ENXIO);
+	for (i = opp_table->regulator_count - 1; i >= 0; i--)
+		regulator_put(opp_table->regulators[i]);
+
+	kfree(opp_table->regulators);
+	opp_table->regulators = NULL;
+	opp_table->regulator_count = 0;
 
 	/* Try freeing opp_table if this was the last blocking resource */
 	_remove_opp_table(opp_table);
@@ -1408,7 +1500,7 @@ void dev_pm_opp_put_regulator(struct device *dev)
 unlock:
 	mutex_unlock(&opp_table_lock);
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulator);
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulators);
 
 /**
  * dev_pm_opp_add()  - Add an OPP table from a table definitions
diff --git a/drivers/base/power/opp/debugfs.c b/drivers/base/power/opp/debugfs.c
index c897676ca35f..95f433db4ac7 100644
--- a/drivers/base/power/opp/debugfs.c
+++ b/drivers/base/power/opp/debugfs.c
@@ -15,6 +15,7 @@
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/limits.h>
+#include <linux/slab.h>
 
 #include "opp.h"
 
@@ -34,6 +35,46 @@ void opp_debug_remove_one(struct dev_pm_opp *opp)
 	debugfs_remove_recursive(opp->dentry);
 }
 
+static bool opp_debug_create_supplies(struct dev_pm_opp *opp,
+				      struct opp_table *opp_table,
+				      struct dentry *pdentry)
+{
+	struct dentry *d;
+	int i = 0;
+	char *name;
+
+	/* Always create at least supply-0 directory */
+	do {
+		name = kasprintf(GFP_KERNEL, "supply-%d", i);
+
+		/* Create per-opp directory */
+		d = debugfs_create_dir(name, pdentry);
+
+		kfree(name);
+
+		if (!d)
+			return false;
+
+		if (!debugfs_create_ulong("u_volt_target", S_IRUGO, d,
+					  &opp->supplies[i].u_volt))
+			return false;
+
+		if (!debugfs_create_ulong("u_volt_min", S_IRUGO, d,
+					  &opp->supplies[i].u_volt_min))
+			return false;
+
+		if (!debugfs_create_ulong("u_volt_max", S_IRUGO, d,
+					  &opp->supplies[i].u_volt_max))
+			return false;
+
+		if (!debugfs_create_ulong("u_amp", S_IRUGO, d,
+					  &opp->supplies[i].u_amp))
+			return false;
+	} while (++i < opp_table->regulator_count);
+
+	return true;
+}
+
 int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 {
 	struct dentry *pdentry = opp_table->dentry;
@@ -63,16 +104,7 @@ int opp_debug_create_one(struct dev_pm_opp *opp, struct opp_table *opp_table)
 	if (!debugfs_create_ulong("rate_hz", S_IRUGO, d, &opp->rate))
 		return -ENOMEM;
 
-	if (!debugfs_create_ulong("u_volt_target", S_IRUGO, d, &opp->supply.u_volt))
-		return -ENOMEM;
-
-	if (!debugfs_create_ulong("u_volt_min", S_IRUGO, d, &opp->supply.u_volt_min))
-		return -ENOMEM;
-
-	if (!debugfs_create_ulong("u_volt_max", S_IRUGO, d, &opp->supply.u_volt_max))
-		return -ENOMEM;
-
-	if (!debugfs_create_ulong("u_amp", S_IRUGO, d, &opp->supply.u_amp))
+	if (!opp_debug_create_supplies(opp, opp_table, d))
 		return -ENOMEM;
 
 	if (!debugfs_create_ulong("clock_latency_ns", S_IRUGO, d,
diff --git a/drivers/base/power/opp/of.c b/drivers/base/power/opp/of.c
index bdf409d42126..3f7d2591b173 100644
--- a/drivers/base/power/opp/of.c
+++ b/drivers/base/power/opp/of.c
@@ -17,6 +17,7 @@
 #include <linux/errno.h>
 #include <linux/device.h>
 #include <linux/of.h>
+#include <linux/slab.h>
 #include <linux/export.h>
 
 #include "opp.h"
@@ -101,16 +102,16 @@ static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
 	return true;
 }
 
-/* TODO: Support multiple regulators */
 static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 			      struct opp_table *opp_table)
 {
-	u32 microvolt[3] = {0};
-	u32 val;
-	int count, ret;
+	u32 *microvolt, *microamp = NULL;
+	int supplies, vcount, icount, ret, i, j;
 	struct property *prop = NULL;
 	char name[NAME_MAX];
 
+	supplies = opp_table->regulator_count ? opp_table->regulator_count : 1;
+
 	/* Search for "opp-microvolt-<name>" */
 	if (opp_table->prop_name) {
 		snprintf(name, sizeof(name), "opp-microvolt-%s",
@@ -128,34 +129,29 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 			return 0;
 	}
 
-	count = of_property_count_u32_elems(opp->np, name);
-	if (count < 0) {
+	vcount = of_property_count_u32_elems(opp->np, name);
+	if (vcount < 0) {
 		dev_err(dev, "%s: Invalid %s property (%d)\n",
-			__func__, name, count);
-		return count;
+			__func__, name, vcount);
+		return vcount;
 	}
 
-	/* There can be one or three elements here */
-	if (count != 1 && count != 3) {
-		dev_err(dev, "%s: Invalid number of elements in %s property (%d)\n",
-			__func__, name, count);
+	/* There can be one or three elements per supply */
+	if (vcount != supplies && vcount != supplies * 3) {
+		dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
+			__func__, name, vcount, supplies);
 		return -EINVAL;
 	}
 
-	ret = of_property_read_u32_array(opp->np, name, microvolt, count);
+	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
+	if (!microvolt)
+		return -ENOMEM;
+
+	ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
 	if (ret) {
 		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
-		return -EINVAL;
-	}
-
-	opp->supply.u_volt = microvolt[0];
-
-	if (count == 1) {
-		opp->supply.u_volt_min = opp->supply.u_volt;
-		opp->supply.u_volt_max = opp->supply.u_volt;
-	} else {
-		opp->supply.u_volt_min = microvolt[1];
-		opp->supply.u_volt_max = microvolt[2];
+		ret = -EINVAL;
+		goto free_microvolt;
 	}
 
 	/* Search for "opp-microamp-<name>" */
@@ -172,10 +168,59 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 		prop = of_find_property(opp->np, name, NULL);
 	}
 
-	if (prop && !of_property_read_u32(opp->np, name, &val))
-		opp->supply.u_amp = val;
+	if (prop) {
+		icount = of_property_count_u32_elems(opp->np, name);
+		if (icount < 0) {
+			dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
+				name, icount);
+			ret = icount;
+			goto free_microvolt;
+		}
 
-	return 0;
+		if (icount != supplies) {
+			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
+				__func__, name, icount, supplies);
+			ret = -EINVAL;
+			goto free_microvolt;
+		}
+
+		microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
+		if (!microamp) {
+			ret = -EINVAL;
+			goto free_microvolt;
+		}
+
+		ret = of_property_read_u32_array(opp->np, name, microamp,
+						 icount);
+		if (ret) {
+			dev_err(dev, "%s: error parsing %s: %d\n", __func__,
+				name, ret);
+			ret = -EINVAL;
+			goto free_microamp;
+		}
+	}
+
+	for (i = 0, j = 0; i < supplies; i++) {
+		opp->supplies[i].u_volt = microvolt[j++];
+
+		if (vcount == supplies) {
+			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
+			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
+		} else {
+			opp->supplies[i].u_volt_min = microvolt[j++];
+			opp->supplies[i].u_volt_max = microvolt[j++];
+		}
+
+		if (microamp)
+			opp->supplies[i].u_amp = microamp[i];
+	}
+
+free_microamp:
+	kfree(microamp);
+free_microvolt:
+	kfree(microvolt);
+
+	return ret;
 }
 
 /**
@@ -304,8 +349,8 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
 
 	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
 		 __func__, new_opp->turbo, new_opp->rate,
-		 new_opp->supply.u_volt, new_opp->supply.u_volt_min,
-		 new_opp->supply.u_volt_max, new_opp->clock_latency_ns);
+		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
+		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);
 
 	/*
 	 * Notify the changes in the availability of the operable
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 8a02516542c2..5b0f7e53bede 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -61,7 +61,7 @@ extern struct list_head opp_tables;
  * @turbo:	true if turbo (boost) OPP
  * @suspend:	true if suspend OPP
  * @rate:	Frequency in hertz
- * @supply:	Power supply voltage/current values
+ * @supplies:	Power supplies voltage/current values
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  *		frequency from any other OPP's frequency.
  * @opp_table:	points back to the opp_table struct this opp belongs to
@@ -80,7 +80,7 @@ struct dev_pm_opp {
 	bool suspend;
 	unsigned long rate;
 
-	struct dev_pm_opp_supply supply;
+	struct dev_pm_opp_supply *supplies;
 
 	unsigned long clock_latency_ns;
 
@@ -139,7 +139,8 @@ enum opp_table_access {
  * @supported_hw_count: Number of elements in supported_hw array.
  * @prop_name: A name to postfix to many DT properties, while parsing them.
  * @clk: Device's clock handle
- * @regulator: Supply regulator
+ * @regulators: Supply regulators
+ * @regulator_count: Number of power supply regulators
  * @dentry:	debugfs dentry pointer of the real device directory (not links).
  * @dentry_name: Name of the real dentry.
  *
@@ -174,7 +175,8 @@ struct opp_table {
 	unsigned int supported_hw_count;
 	const char *prop_name;
 	struct clk *clk;
-	struct regulator *regulator;
+	struct regulator **regulators;
+	unsigned int regulator_count;
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
index 5c07ae05d69a..15cb26118dc7 100644
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -186,7 +186,10 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 	 */
 	name = find_supply_name(cpu_dev);
 	if (name) {
-		ret = dev_pm_opp_set_regulator(cpu_dev, name);
+		const char *names[] = {name};
+
+		ret = dev_pm_opp_set_regulators(cpu_dev, names,
+						ARRAY_SIZE(names));
 		if (ret) {
 			dev_err(cpu_dev, "Failed to set regulator for cpu%d: %d\n",
 				policy->cpu, ret);
@@ -285,7 +288,7 @@ static int cpufreq_init(struct cpufreq_policy *policy)
 out_free_opp:
 	dev_pm_opp_of_cpumask_remove_table(policy->cpus);
 	if (name)
-		dev_pm_opp_put_regulator(cpu_dev);
+		dev_pm_opp_put_regulators(cpu_dev);
 out_put_clk:
 	clk_put(cpu_clk);
 
@@ -300,7 +303,7 @@ static int cpufreq_exit(struct cpufreq_policy *policy)
 	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 	dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
 	if (priv->reg_name)
-		dev_pm_opp_put_regulator(priv->cpu_dev);
+		dev_pm_opp_put_regulators(priv->cpu_dev);
 
 	clk_put(policy->clk);
 	kfree(priv);
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index f69126e2bb59..27eea9bfc5ed 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -78,8 +78,8 @@ int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
 void dev_pm_opp_put_supported_hw(struct device *dev);
 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_regulators(struct device *dev, const char * const names[], unsigned int count);
+void dev_pm_opp_put_regulators(struct device *dev);
 int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq);
 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cpumask);
 int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);
@@ -186,12 +186,12 @@ static inline int dev_pm_opp_set_prop_name(struct device *dev, const char *name)
 
 static inline void dev_pm_opp_put_prop_name(struct device *dev) {}
 
-static inline int dev_pm_opp_set_regulator(struct device *dev, const char *name)
+static inline int dev_pm_opp_set_regulators(struct device *dev, const char *names[], unsigned int count)
 {
 	return -ENOTSUPP;
 }
 
-static inline void dev_pm_opp_put_regulator(struct device *dev) {}
+static inline void dev_pm_opp_put_regulators(struct device *dev) {}
 
 static inline int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 {
-- 
2.7.1.410.g6faf27b

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#1531934 — [PATCH V5 02/10] PM / OPP: Reword binding supporting multiple regulators per device

On certain platforms (like TI), DVFS for a single device (CPU) requires
configuring multiple power supplies.

The OPP bindings already contains binding and example to explain this
case, but it isn't sufficient.

- There is no way for the code parsing these bindings to know which
  voltage values belong to which power supply.

- It is not possible to know the order in which the supplies need to be
  configured while switching OPPs.

This patch clarifies on those details by mentioning that such
information is left for the implementation specific bindings to explain.
They may want to hardcode such details or implement their own properties
to get such information. All implementations using multiple regulators
for their devices must provide a binding document explaining their
implementation.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
---
 Documentation/devicetree/bindings/opp/opp.txt | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
index f0239f68d186..9f5ca4457b5f 100644
--- a/Documentation/devicetree/bindings/opp/opp.txt
+++ b/Documentation/devicetree/bindings/opp/opp.txt
@@ -86,8 +86,14 @@ properties.
   Single entry is for target voltage and three entries are for <target min max>
   voltages.
 
-  Entries for multiple regulators must be present in the same order as
-  regulators are specified in device's DT node.
+  Entries for multiple regulators shall be provided in the same field separated
+  by angular brackets <>. The OPP binding doesn't provide any provisions to
+  relate the values to their power supplies or the order in which the supplies
+  need to be configured and that is left for the implementation specific
+  binding.
+
+  Entries for all regulators shall be of the same size, i.e. either all use a
+  single value or triplets.
 
 - opp-microvolt-<name>: Named opp-microvolt property. This is exactly similar to
   the above opp-microvolt property, but allows multiple voltage ranges to be
@@ -104,10 +110,13 @@ properties.
 
   Should only be set if opp-microvolt is set for the OPP.
 
-  Entries for multiple regulators must be present in the same order as
-  regulators are specified in device's DT node. If this property isn't required
-  for few regulators, then this should be marked as zero for them. If it isn't
-  required for any regulator, then this property need not be present.
+  Entries for multiple regulators shall be provided in the same field separated
+  by angular brackets <>. If current values aren't required for a regulator,
+  then it shall be filled with 0. If current values aren't required for any of
+  the regulators, then this field is not required. The OPP binding doesn't
+  provide any provisions to relate the values to their power supplies or the
+  order in which the supplies need to be configured and that is left for the
+  implementation specific binding.
 
 - opp-microamp-<name>: Named opp-microamp property. Similar to
   opp-microvolt-<name> property, but for microamp instead.
-- 
2.7.1.410.g6faf27b

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#1531940 — [PATCH V5 03/10] PM / OPP: Don't use OPP structure outside of rcu protected section

The OPP structure must not be used out of the rcu protected section.
Cache the values to be used in separate variables instead.

Cc:  # v4.6+ <stable@vger.kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Dave Gerlach <d-gerlach@ti.com>
---
 drivers/base/power/opp/core.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 4c7c6da7a989..056527a3fb4e 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -584,6 +584,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	struct clk *clk;
 	unsigned long freq, old_freq;
 	unsigned long u_volt, u_volt_min, u_volt_max;
+	unsigned long old_u_volt, old_u_volt_min, old_u_volt_max;
 	int ret;
 
 	if (unlikely(!target_freq)) {
@@ -633,6 +634,14 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 		return ret;
 	}
 
+	if (IS_ERR(old_opp)) {
+		old_u_volt = 0;
+	} else {
+		old_u_volt = old_opp->u_volt;
+		old_u_volt_min = old_opp->u_volt_min;
+		old_u_volt_max = old_opp->u_volt_max;
+	}
+
 	u_volt = opp->u_volt;
 	u_volt_min = opp->u_volt_min;
 	u_volt_max = opp->u_volt_max;
@@ -677,9 +686,10 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 			__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, old_opp->u_volt,
-				 old_opp->u_volt_min, old_opp->u_volt_max);
+	if (old_u_volt) {
+		_set_opp_voltage(dev, reg, old_u_volt, old_u_volt_min,
+				 old_u_volt_max);
+	}
 
 	return ret;
 }
-- 
2.7.1.410.g6faf27b

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#1532254

On Tue, Nov 29, 2016 at 7:36 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> Hi,
>
> Some platforms (like TI) have complex DVFS configuration for CPU
> devices, where multiple regulators are required to be configured to
> change DVFS state of the device. This was explained well by Nishanth
> earlier [1].
>
> One of the major complaints around multiple regulators case was that the
> DT isn't responsible in any way to represent the order in which multiple
> supplies need to be programmed, before or after a frequency change. It
> was considered in this patch and such information is left for the
> platform specific OPP driver now, which can register its own
> opp_set_rate() callback with the OPP core and the OPP core will then
> call it during DVFS.
>
> The patches are tested on Exynos5250 (Dual A15). I have hacked around DT
> and code to pass values for multiple regulators and verified that they
> are all properly read by the kernel (using debugfs interface).
>
> Dave Gerlach has already tested [2] it on the real TI platforms and it
> works well for him.
>
> This is rebased over: linux-next branch in the PM tree.
>
> V4->V5:
> - Stephen boyd had some minor review comments and gave his Reviewed-by
>   tag for the rest. Only 2 patches don't have his RBY tag.
> - Individual patches contain the version history from V4 to V5.

Cool.

I'd still like to see that everyone agrees with patch [6/10] in particular.

Thanks,
Rafael

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