[PATCH v6 6/7] drm/panthor: Use existing OPP table if present

[Nicolas Frattaroli <nicolas.frattaroli@collabora.com>]

On SoCs where the GPU's power-domain is in charge of setting performance
levels, the OPP table of the GPU node will have already been populated
during said power-domain's attach_dev operation.

To avoid initialising an OPP table twice, only set the OPP regulator and
the OPPs from DT if there's no OPP table present.

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
---
 drivers/gpu/drm/panthor/panthor_devfreq.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c
index 978f193a2aee561fadd9a976e9b1417118260889..6beb6170d6eea3dd65880dfe64a61abbdd5f08da 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.c
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.c
@@ -143,6 +143,7 @@ int panthor_devfreq_init(struct panthor_device *ptdev)
 	struct panthor_devfreq *pdevfreq;
 	struct dev_pm_opp *opp;
 	unsigned long cur_freq;
+	struct opp_table *t;
 	unsigned long freq = ULONG_MAX;
 	int ret;
 
@@ -152,18 +153,23 @@ int panthor_devfreq_init(struct panthor_device *ptdev)
 
 	ptdev->devfreq = pdevfreq;
 
-	ret = devm_pm_opp_set_regulators(dev, reg_names);
-	if (ret) {
-		if (ret != -EPROBE_DEFER)
-			DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
-
-		return ret;
+	t = dev_pm_opp_get_opp_table(dev);
+	if (IS_ERR_OR_NULL(t)) {
+		ret = devm_pm_opp_set_regulators(dev, reg_names);
+		if (ret) {
+			if (ret != -EPROBE_DEFER)
+				DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
+
+			return ret;
+		}
+
+		ret = devm_pm_opp_of_add_table(dev);
+		if (ret)
+			return ret;
+	} else {
+		dev_pm_opp_put_opp_table(t);
 	}
 
-	ret = devm_pm_opp_of_add_table(dev);
-	if (ret)
-		return ret;
-
 	spin_lock_init(&pdevfreq->lock);
 
 	panthor_devfreq_reset(pdevfreq);

-- 
2.51.0