drm/panfrost: add regulators to devfreq

Some OPP tables specify voltage for each frequency. Devfreq can
handle these regulators but they should be get only 1 time to avoid
issue and know who is in charge.

If OPP table is probe don't init regulator.
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200710095409.407087-11-peron.clem@gmail.com

drivers/gpu/drm/panfrost/panfrost_devfreq.c

@@ -93,14 +93,30 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
 	unsigned long cur_freq;
 	struct device *dev = &pfdev->pdev->dev;
 	struct devfreq *devfreq;
+	struct opp_table *opp_table;
 	struct thermal_cooling_device *cooling;
 	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 
+	opp_table = dev_pm_opp_set_regulators(dev, pfdev->comp->supply_names,
+					      pfdev->comp->num_supplies);
+	if (IS_ERR(opp_table)) {
+		ret = PTR_ERR(opp_table);
+		/* Continue if the optional regulator is missing */
+		if (ret != -ENODEV) {
+			DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
+			goto err_fini;
+		}
+	} else {
+		pfdevfreq->regulators_opp_table = opp_table;
+	}
+
 	ret = dev_pm_opp_of_add_table(dev);
-	if (ret == -ENODEV) /* Optional, continue without devfreq */
-		return 0;
-	else if (ret)
-		return ret;
+	if (ret) {
+		/* Optional, continue without devfreq */
+		if (ret == -ENODEV)
+			ret = 0;
+		goto err_fini;
+	}
 	pfdevfreq->opp_of_table_added = true;
 
 	spin_lock_init(&pfdevfreq->lock);
@@ -153,6 +169,11 @@ void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 		dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
 		pfdevfreq->opp_of_table_added = false;
 	}
+
+	if (pfdevfreq->regulators_opp_table) {
+		dev_pm_opp_put_regulators(pfdevfreq->regulators_opp_table);
+		pfdevfreq->regulators_opp_table = NULL;
+	}
 }
 
 void panfrost_devfreq_resume(struct panfrost_device *pfdev)

drivers/gpu/drm/panfrost/panfrost_devfreq.h

@@ -8,12 +8,14 @@
 #include <linux/ktime.h>
 
 struct devfreq;
+struct opp_table;
 struct thermal_cooling_device;
 
 struct panfrost_device;
 
 struct panfrost_devfreq {
 	struct devfreq *devfreq;
+	struct opp_table *regulators_opp_table;
 	struct thermal_cooling_device *cooling;
 	bool opp_of_table_added;
 

drivers/gpu/drm/panfrost/panfrost_device.c

@@ -225,9 +225,12 @@ int panfrost_device_init(struct panfrost_device *pfdev)
 		goto out_clk;
 	}
 
-	err = panfrost_regulator_init(pfdev);
-	if (err)
-		goto out_devfreq;
+	/* OPP will handle regulators */
+	if (!pfdev->pfdevfreq.opp_of_table_added) {
+		err = panfrost_regulator_init(pfdev);
+		if (err)
+			goto out_devfreq;
+	}
 
 	err = panfrost_reset_init(pfdev);
 	if (err) {