OPP: Simplify opp_parse_supplies() by restructuring it

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.
Tested-by: James Calligeros <jcalligeros99@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

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 (!prop)
+			return NULL;
 	}
 
-			if (!supplies)
-				return 0;
-
-			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
-				__func__);
-			return -EINVAL;
-		}
+	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);
 	}
 
-	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;
-	}
+	/*
+	 * 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;
 
-	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;
+	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);
 	}
 
-	/* 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;
-	}
+	out = kmalloc_array(count, sizeof(*out), GFP_KERNEL);
+	if (!out)
+		return ERR_PTR(-EINVAL);
 
-	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
-	if (!microvolt)
-		return -ENOMEM;
-
-	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);
-	}
+	return out;
+}
 
-	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;
-		}
+static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
+				struct opp_table *opp_table, bool *triplet)
+{
+	u32 *microvolt;
 
-		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;
-		}
+	microvolt = _parse_named_prop(opp, dev, opp_table, "microvolt", triplet);
+	if (IS_ERR(microvolt))
+		return 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;
+	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);
-	}
+	return microvolt;
+}
 
-	if (!prop) {
-		/* Search for "opp-microwatt" */
-		sprintf(name, "opp-microwatt");
-		prop = of_find_property(opp->np, name, NULL);
-	}
+static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
+			      struct opp_table *opp_table)
+{
+	u32 *microvolt, *microamp, *microwatt;
+	int ret = 0, i, j;
+	bool triplet;
 
-	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;
-		}
+	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
+	if (IS_ERR_OR_NULL(microvolt))
+		return PTR_ERR(microvolt);
 
-		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;
+	microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
+	if (IS_ERR(microamp)) {
+		ret = PTR_ERR(microamp);
+		goto free_microvolt;
 	}
 
-		microwatt = kmalloc_array(pcount, sizeof(*microwatt),
-					  GFP_KERNEL);
-		if (!microwatt) {
-			ret = -EINVAL;
+	microwatt = _parse_named_prop(opp, dev, opp_table, "microwatt", NULL);
+	if (IS_ERR(microwatt)) {
+		ret = PTR_ERR(microwatt);
 		goto free_microamp;
 	}
 
-		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;
-		}
-	}
-
-	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);