[PATCH 0/5] OPP: Allow power/current values without voltage

[PATCH 0/5] OPP: Allow power/current values without voltage

[Viresh Kumar]

Hello,

Some platforms, such as Apple Silicon, do not describe their device's
voltage regulators in the DT as they cannot be controlled by the kernel
and/or rely on opaque firmware algorithms to control their voltage and
current characteristics at runtime. They can, however, experimentally
determine the power consumption of a given device at a given OPP, taking
advantage of opp-microwatt to provide EAS on such devices as was initially
intended.

But the OPP core currently doesn't parse the opp-microwatt property if
opp-microvolt isn't present. This patch series targets to change this approach.

This first fixes few mistakes in the DT bindings, followed by code
reorganization. And the last commit, from James, fixes the problem at hand.

I have tested all combinations on my Hikey board, hope it doesn't break
anything.

James Calligeros (1):
  OPP: decouple dt properties in opp_parse_supplies()

Viresh Kumar (4):
  dt-bindings: opp: Fix usage of current in microwatt property
  dt-bindings: opp: Fix named microwatt property
  OPP: Parse named opp-microwatt property too
  OPP: Simplify opp_parse_supplies() by restructuring it

 .../devicetree/bindings/opp/opp-v2-base.yaml  |   6 +-
 drivers/opp/of.c                              | 228 ++++++++----------
 2 files changed, 102 insertions(+), 132 deletions(-)

-- 
2.31.1.272.g89b43f80a514

[PATCH 1/5] dt-bindings: opp: Fix usage of current in microwatt property

[Viresh Kumar]

The bindings mentions "current" instead of "power". Fix it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 Documentation/devicetree/bindings/opp/opp-v2-base.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/opp/opp-v2-base.yaml b/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
index 66d0ec763f0b..cb025b0a346d 100644
--- a/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
+++ b/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
@@ -108,7 +108,7 @@ select: false
           The power for the OPP in micro-Watts.
 
           Entries for multiple regulators shall be provided in the same field
-          separated by angular brackets <>. If current values aren't required
+          separated by angular brackets <>. If power values aren't required
           for a regulator, then it shall be filled with 0. If power 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
-- 
2.31.1.272.g89b43f80a514

[PATCH 2/5] dt-bindings: opp: Fix named microwatt property

[Viresh Kumar]

The named microwatt-<name> property should look exactly like microvolt
and microamp properties. There were some differences, fix them.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 Documentation/devicetree/bindings/opp/opp-v2-base.yaml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/opp/opp-v2-base.yaml b/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
index cb025b0a346d..cf9c2f7bddc2 100644
--- a/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
+++ b/Documentation/devicetree/bindings/opp/opp-v2-base.yaml
@@ -230,9 +230,9 @@ select: false
         minItems: 1
         maxItems: 8   # Should be enough regulators
 
-      '^opp-microwatt':
+      '^opp-microwatt-':
         description:
-          Named opp-microwatt property. Similar to opp-microamp property,
+          Named opp-microwatt property. Similar to opp-microamp-<name> property,
           but for microwatt instead.
         $ref: /schemas/types.yaml#/definitions/uint32-array
         minItems: 1
-- 
2.31.1.272.g89b43f80a514

[PATCH 3/5] OPP: Parse named opp-microwatt property too

[Viresh Kumar]

We missed parsing the named opp-microwatt-<name> property, fix that.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/opp/of.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 605d68673f92..e010e119c42b 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -695,9 +695,19 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 		}
 	}
 
-	/* Search for "opp-microwatt" */
-	sprintf(name, "opp-microwatt");
-	prop = of_find_property(opp->np, name, NULL);
+	/* Search for "opp-microwatt-<name>" */
+	prop = NULL;
+	if (opp_table->prop_name) {
+		snprintf(name, sizeof(name), "opp-microwatt-%s",
+			 opp_table->prop_name);
+		prop = of_find_property(opp->np, name, NULL);
+	}
+
+	if (!prop) {
+		/* Search for "opp-microwatt" */
+		sprintf(name, "opp-microwatt");
+		prop = of_find_property(opp->np, name, NULL);
+	}
 
 	if (prop) {
 		pcount = of_property_count_u32_elems(opp->np, name);
-- 
2.31.1.272.g89b43f80a514

[PATCH 4/5] OPP: Simplify opp_parse_supplies() by restructuring it

[Viresh Kumar]

opp_parse_supplies() has grown into too big of a routine (~190 lines)
and it is not straight-forward to understand it anymore.

Break it into smaller routines and reduce code redundancy a bit by using
the same code to parse properties.

This shouldn't result in any logical changes.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/opp/of.c | 216 ++++++++++++++++++-----------------------------
 1 file changed, 81 insertions(+), 135 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index e010e119c42b..e51c43495e21 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -578,179 +578,126 @@ static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
 	return false;
 }
 
-static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
-			      struct opp_table *opp_table)
+static u32 *_parse_named_prop(struct dev_pm_opp *opp, struct device *dev,
+			      struct opp_table *opp_table,
+			      const char *prop_type, bool *triplet)
 {
-	u32 *microvolt, *microamp = NULL, *microwatt = NULL;
-	int supplies = opp_table->regulator_count;
-	int vcount, icount, pcount, ret, i, j;
 	struct property *prop = NULL;
 	char name[NAME_MAX];
+	int count, ret;
+	u32 *out;
 
-	/* Search for "opp-microvolt-<name>" */
+	/* Search for "opp-<prop_type>-<name>" */
 	if (opp_table->prop_name) {
-		snprintf(name, sizeof(name), "opp-microvolt-%s",
+		snprintf(name, sizeof(name), "opp-%s-%s", prop_type,
 			 opp_table->prop_name);
 		prop = of_find_property(opp->np, name, NULL);
 	}
 
 	if (!prop) {
-		/* Search for "opp-microvolt" */
-		sprintf(name, "opp-microvolt");
+		/* Search for "opp-<prop_type>" */
+		snprintf(name, sizeof(name), "opp-%s", prop_type);
 		prop = of_find_property(opp->np, name, NULL);
-
-		/* Missing property isn't a problem, but an invalid entry is */
-		if (!prop) {
-			if (unlikely(supplies == -1)) {
-				/* Initialize regulator_count */
-				opp_table->regulator_count = 0;
-				return 0;
-			}
-
-			if (!supplies)
-				return 0;
-
-			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
-				__func__);
-			return -EINVAL;
-		}
-	}
-
-	if (unlikely(supplies == -1)) {
-		/* Initialize regulator_count */
-		supplies = opp_table->regulator_count = 1;
-	} else if (unlikely(!supplies)) {
-		dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
-		return -EINVAL;
+		if (!prop)
+			return NULL;
 	}
 
-	vcount = of_property_count_u32_elems(opp->np, name);
-	if (vcount < 0) {
-		dev_err(dev, "%s: Invalid %s property (%d)\n",
-			__func__, name, vcount);
-		return vcount;
+	count = of_property_count_u32_elems(opp->np, name);
+	if (count < 0) {
+		dev_err(dev, "%s: Invalid %s property (%d)\n", __func__, name,
+			count);
+		return ERR_PTR(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;
+	/*
+	 * Initialize regulator_count, if regulator information isn't provided
+	 * by the platform. Now that one of the properties is available, fix the
+	 * regulator_count to 1.
+	 */
+	if (unlikely(opp_table->regulator_count == -1))
+		opp_table->regulator_count = 1;
+
+	if (count != opp_table->regulator_count &&
+	    (!triplet || count != opp_table->regulator_count * 3)) {
+		dev_err(dev, "%s: Invalid number of elements in %s property (%u) with supplies (%d)\n",
+			__func__, prop_type, count, opp_table->regulator_count);
+		return ERR_PTR(-EINVAL);
 	}
 
-	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
-	if (!microvolt)
-		return -ENOMEM;
+	out = kmalloc_array(count, sizeof(*out), GFP_KERNEL);
+	if (!out)
+		return ERR_PTR(-EINVAL);
 
-	ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
+	ret = of_property_read_u32_array(opp->np, name, out, count);
 	if (ret) {
 		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
-		ret = -EINVAL;
-		goto free_microvolt;
+		kfree(out);
+		return ERR_PTR(-EINVAL);
 	}
 
-	/* Search for "opp-microamp-<name>" */
-	prop = NULL;
-	if (opp_table->prop_name) {
-		snprintf(name, sizeof(name), "opp-microamp-%s",
-			 opp_table->prop_name);
-		prop = of_find_property(opp->np, name, NULL);
-	}
+	if (triplet)
+		*triplet = count != opp_table->regulator_count;
 
-	if (!prop) {
-		/* Search for "opp-microamp" */
-		sprintf(name, "opp-microamp");
-		prop = of_find_property(opp->np, name, NULL);
-	}
-
-	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 out;
+}
 
-		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;
-		}
+static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
+				struct opp_table *opp_table, bool *triplet)
+{
+	u32 *microvolt;
 
-		microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
-		if (!microamp) {
-			ret = -EINVAL;
-			goto free_microvolt;
-		}
+	microvolt = _parse_named_prop(opp, dev, opp_table, "microvolt", triplet);
+	if (IS_ERR(microvolt))
+		return 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;
+	if (!microvolt) {
+		/*
+		 * Missing property isn't a problem, but an invalid
+		 * entry is. This property isn't optional if regulator
+		 * information is provided.
+		 */
+		if (opp_table->regulator_count > 0) {
+			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
+				__func__);
+			return ERR_PTR(-EINVAL);
 		}
 	}
 
-	/* Search for "opp-microwatt-<name>" */
-	prop = NULL;
-	if (opp_table->prop_name) {
-		snprintf(name, sizeof(name), "opp-microwatt-%s",
-			 opp_table->prop_name);
-		prop = of_find_property(opp->np, name, NULL);
-	}
-
-	if (!prop) {
-		/* Search for "opp-microwatt" */
-		sprintf(name, "opp-microwatt");
-		prop = of_find_property(opp->np, name, NULL);
-	}
+	return microvolt;
+}
 
-	if (prop) {
-		pcount = of_property_count_u32_elems(opp->np, name);
-		if (pcount < 0) {
-			dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
-				name, pcount);
-			ret = pcount;
-			goto free_microamp;
-		}
+static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
+			      struct opp_table *opp_table)
+{
+	u32 *microvolt, *microamp, *microwatt;
+	int ret, i, j;
+	bool triplet;
 
-		if (pcount != supplies) {
-			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
-				__func__, name, pcount, supplies);
-			ret = -EINVAL;
-			goto free_microamp;
-		}
+	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
+	if (IS_ERR_OR_NULL(microvolt))
+		return PTR_ERR(microvolt);
 
-		microwatt = kmalloc_array(pcount, sizeof(*microwatt),
-					  GFP_KERNEL);
-		if (!microwatt) {
-			ret = -EINVAL;
-			goto free_microamp;
-		}
+	microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
+	if (IS_ERR(microamp)) {
+		ret = PTR_ERR(microamp);
+		goto free_microvolt;
+	}
 
-		ret = of_property_read_u32_array(opp->np, name, microwatt,
-						 pcount);
-		if (ret) {
-			dev_err(dev, "%s: error parsing %s: %d\n", __func__,
-				name, ret);
-			ret = -EINVAL;
-			goto free_microwatt;
-		}
+	microwatt = _parse_named_prop(opp, dev, opp_table, "microwatt", NULL);
+	if (IS_ERR(microwatt)) {
+		ret = PTR_ERR(microwatt);
+		goto free_microamp;
 	}
 
-	for (i = 0, j = 0; i < supplies; i++) {
+	for (i = 0, j = 0; i < opp_table->regulator_count; 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 {
+		if (triplet) {
 			opp->supplies[i].u_volt_min = microvolt[j++];
 			opp->supplies[i].u_volt_max = microvolt[j++];
+		} else {
+			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
+			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
 		}
 
 		if (microamp)
@@ -760,7 +707,6 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 			opp->supplies[i].u_watt = microwatt[i];
 	}
 
-free_microwatt:
 	kfree(microwatt);
 free_microamp:
 	kfree(microamp);
-- 
2.31.1.272.g89b43f80a514

[PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[Viresh Kumar]

From: James Calligeros <jcalligeros99@gmail.com>

The opp-microwatt property was added with the intention of providing
platforms a way to specify a precise value for the power consumption
of a device at a given OPP to enable better energy-aware scheduling
decisions by informing the kernel of the total static and dynamic
power of a device at a given OPP, removing the reliance on the EM
subsystem's often flawed estimations. This property is parsed by
opp_parse_supplies(), which creates a hard dependency on the
opp-microvolt property.

Some platforms, such as Apple Silicon, do not describe their device's
voltage regulators in the DT as they cannot be controlled by the kernel
and/or rely on opaque firmware algorithms to control their voltage and
current characteristics at runtime. We can, however, experimentally
determine the power consumption of a given device at a given OPP, taking
advantage of opp-microwatt to provide EAS on such devices as was
initially intended.

Allow platforms to specify and consume any subset of opp-microvolt,
opp-microamp, or opp-microwatt without a hard dependency on
opp-microvolt to enable this functionality on such platforms.

Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V2: Rewritten by Viresh on top of his changes.

 drivers/opp/of.c | 36 +++++++++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index e51c43495e21..273fa9c0e1c0 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -654,9 +654,12 @@ static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
 		/*
 		 * Missing property isn't a problem, but an invalid
 		 * entry is. This property isn't optional if regulator
-		 * information is provided.
+		 * information is provided. Check only for the first OPP, as
+		 * regulator_count may get initialized after that to a valid
+		 * value.
 		 */
-		if (opp_table->regulator_count > 0) {
+		if (list_empty(&opp_table->opp_list) &&
+		    opp_table->regulator_count > 0) {
 			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
 				__func__);
 			return ERR_PTR(-EINVAL);
@@ -674,7 +677,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 	bool triplet;
 
 	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
-	if (IS_ERR_OR_NULL(microvolt))
+	if (IS_ERR(microvolt))
 		return PTR_ERR(microvolt);
 
 	microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
@@ -689,15 +692,26 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 		goto free_microamp;
 	}
 
-	for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
-		opp->supplies[i].u_volt = microvolt[j++];
+	/*
+	 * Initialize regulator_count if it is uninitialized and no properties
+	 * are found.
+	 */
+	if (unlikely(opp_table->regulator_count == -1)) {
+		opp_table->regulator_count = 0;
+		return 0;
+	}
 
-		if (triplet) {
-			opp->supplies[i].u_volt_min = microvolt[j++];
-			opp->supplies[i].u_volt_max = microvolt[j++];
-		} else {
-			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
-			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
+	for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
+		if (microvolt) {
+			opp->supplies[i].u_volt = microvolt[j++];
+
+			if (triplet) {
+				opp->supplies[i].u_volt_min = microvolt[j++];
+				opp->supplies[i].u_volt_max = microvolt[j++];
+			} else {
+				opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
+				opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
+			}
 		}
 
 		if (microamp)
-- 
2.31.1.272.g89b43f80a514

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[James Calligeros]

On Thursday, 3 November 2022 9:01:08 PM AEST Viresh Kumar wrote:

> @@ -674,7 +677,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
>  	bool triplet;
>  
>  	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
> -	if (IS_ERR_OR_NULL(microvolt))
> +	if (IS_ERR(microvolt))
>  		return PTR_ERR(microvolt);
 
Erroring out here will still block EM registration on platforms without 
the opp-microvolt prop so we're back to square one, which means the 
patch does not do what the description says it does. It behaves
almost identically to the current code.

I assume this is an intentional choice given the comments in
opp_parse_microvolt(), so the commit message should drop 
references to fixing such platforms.

If this is a hard sticking point and opp_parse_supplies() must return
a regulator with opp-microvolt, then I am of the opinion that the parsing
of opp-microwatt should be detangled entirely from the regulator
infrastructure.

Otherwise for the whole series,

Tested-by: James Calligeros <jcalligeros99@gmail.com>

- James

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[Viresh Kumar]

On 03-11-22, 22:24, James Calligeros wrote:
> On Thursday, 3 November 2022 9:01:08 PM AEST Viresh Kumar wrote:
> 
> > @@ -674,7 +677,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
> >  	bool triplet;
> >  
> >  	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
> > -	if (IS_ERR_OR_NULL(microvolt))
> > +	if (IS_ERR(microvolt))
> >  		return PTR_ERR(microvolt);
>  
> Erroring out here will still block EM registration on platforms without 
> the opp-microvolt prop so we're back to square one, which means the 
> patch does not do what the description says it does. It behaves
> almost identically to the current code.

I am confused.

With the current code, the following will work:
- all three available
- microvolt available and nothing else.
- only microamp available
- only microwatt available
- both microamp and microwatt available but no microvolt
- and other combinations

Isn't this all we want ?

We error out here when there is a problem with DT entries, i.e. incorrect
entries, etc. Else we will get NULL here and we continue as we don't check for
IS_ERR_OR_NULL() anymore after this patch.

> I assume this is an intentional choice given the comments in
> opp_parse_microvolt(), so the commit message should drop 
> references to fixing such platforms.
> 
> If this is a hard sticking point and opp_parse_supplies() must return
> a regulator with opp-microvolt, then I am of the opinion that the parsing
> of opp-microwatt should be detangled entirely from the regulator
> infrastructure.
> 
> Otherwise for the whole series,
> 
> Tested-by: James Calligeros <jcalligeros99@gmail.com>

What did you test exactly ? As I thought you will be testing the only microwatt
case here and you say it won't work.

Sorry, I just got a little bit confused :(

-- 
viresh

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[James Calligeros]

On Thursday, 3 November 2022 11:10:51 PM AEST Viresh Kumar wrote:
> On 03-11-22, 22:24, James Calligeros wrote:
> > On Thursday, 3 November 2022 9:01:08 PM AEST Viresh Kumar wrote:
> > 
> > > @@ -674,7 +677,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
> > >  	bool triplet;
> > >  
> > >  	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
> > > -	if (IS_ERR_OR_NULL(microvolt))
> > > +	if (IS_ERR(microvolt))
> > >  		return PTR_ERR(microvolt);
> >  
> > Erroring out here will still block EM registration on platforms without 
> > the opp-microvolt prop so we're back to square one, which means the 
> > patch does not do what the description says it does. It behaves
> > almost identically to the current code.
> 
> I am confused.
> 
> With the current code, the following will work:
> - all three available
> - microvolt available and nothing else.
> - only microamp available
> - only microwatt available
> - both microamp and microwatt available but no microvolt
> - and other combinations
> 
> Isn't this all we want ?

You're right, I misinterpreted an error. Details as below.

> What did you test exactly ? As I thought you will be testing the only microwatt
> case here and you say it won't work.
> 
> Sorry, I just got a little bit confused :(
> 

I did test on the Apple machine with only opp-microwatt, but I misinterpreted
the error. We end up here upon parsing the second OPP:

>if (list_empty(&opp_table->opp_list) &&
>    opp_table->regulator_count > 0) {
>	dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
>		__func__);
>	return ERR_PTR(-EINVAL);
>}

When this path is removed, things work as expected. Could it be that opp_list has
not been updated by the time we're parsing the next OPP? Seems unlikely, but
at the same time if we're ending up taking this branch then there's not much else
that could have gone wrong.

- James

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[Viresh Kumar]

On 04-11-22, 01:23, James Calligeros wrote:
> >if (list_empty(&opp_table->opp_list) &&
> >    opp_table->regulator_count > 0) {

I did test this and it should have worked for you as well.

> >	dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
> >		__func__);
> >	return ERR_PTR(-EINVAL);
> >}
> 
> When this path is removed, things work as expected. Could it be that opp_list has
> not been updated by the time we're parsing the next OPP? Seems unlikely, but
> at the same time if we're ending up taking this branch then there's not much else
> that could have gone wrong.

It should happen sequentially.

Ahh, I looked code for sometime before I wrote this line. I know what's going
on. Its a bug in the patchset that I fixed yesterday and pushed.

Initialize "ret = 0" in opp_parse_supplies().

Or pick patches from:

git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git opp/linux-next

Sorry for the trouble.

-- 
viresh

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[Viresh Kumar]

On 03-11-22, 16:31, Viresh Kumar wrote:
> From: James Calligeros <jcalligeros99@gmail.com>
> 
> The opp-microwatt property was added with the intention of providing
> platforms a way to specify a precise value for the power consumption
> of a device at a given OPP to enable better energy-aware scheduling
> decisions by informing the kernel of the total static and dynamic
> power of a device at a given OPP, removing the reliance on the EM
> subsystem's often flawed estimations. This property is parsed by
> opp_parse_supplies(), which creates a hard dependency on the
> opp-microvolt property.
> 
> Some platforms, such as Apple Silicon, do not describe their device's
> voltage regulators in the DT as they cannot be controlled by the kernel
> and/or rely on opaque firmware algorithms to control their voltage and
> current characteristics at runtime. We can, however, experimentally
> determine the power consumption of a given device at a given OPP, taking
> advantage of opp-microwatt to provide EAS on such devices as was
> initially intended.
> 
> Allow platforms to specify and consume any subset of opp-microvolt,
> opp-microamp, or opp-microwatt without a hard dependency on
> opp-microvolt to enable this functionality on such platforms.
> 
> Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
> Co-developed-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> V2: Rewritten by Viresh on top of his changes.
> 
>  drivers/opp/of.c | 36 +++++++++++++++++++++++++-----------
>  1 file changed, 25 insertions(+), 11 deletions(-)

Plus this fix:

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 273fa9c0e1c0..e55c6095adf0 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -673,7 +673,7 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
                              struct opp_table *opp_table)
 {
        u32 *microvolt, *microamp, *microwatt;
-       int ret, i, j;
+       int ret = 0, i, j;
        bool triplet;

        microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);

-- 
viresh

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[James Calligeros]

On Friday, 4 November 2022 3:07:52 PM AEST Viresh Kumar wrote:
> It should happen sequentially.

 I noticed the mutexes after I got some sleep :)

> Initialize "ret = 0" in opp_parse_supplies().
> 
> Or pick patches from:
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git opp/linux-next
> 

It didn't even cross my mind that opp_parse_supplies() returning
ret uninitialised was causing the failure further up the chain. Applied
and tested, everything's working as expected now. 

> Sorry for the trouble.

This is on me, I should have heeded the compiler warning.

- James

Re: [PATCH V2 5/5] OPP: decouple dt properties in opp_parse_supplies()

[Viresh Kumar]

On 04-11-22, 15:25, James Calligeros wrote:
> On Friday, 4 November 2022 3:07:52 PM AEST Viresh Kumar wrote:
> > It should happen sequentially.
> 
>  I noticed the mutexes after I got some sleep :)
> 
> > Initialize "ret = 0" in opp_parse_supplies().
> > 
> > Or pick patches from:
> > 
> > git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm.git opp/linux-next
> > 
> 
> It didn't even cross my mind that opp_parse_supplies() returning
> ret uninitialised was causing the failure further up the chain. Applied
> and tested, everything's working as expected now. 
> 
> > Sorry for the trouble.
> 
> This is on me, I should have heeded the compiler warning.

Thanks James for giving this a try. Really appreciate it. The changes are
applied and pushed for linux-next along with your Tested-by.

-- 
viresh