[RFC PATCH 08/18] drm/panthor: Skip devfreq when no OPP table is present

[Karunika Choo]

On Mali v15 AM systems, frequency scaling is handled outside panthor by
the AM_GOVERNOR block, so the GPU DT node may not provide an OPP table.

Make panthor_devfreq_init() return early when operating-points-v2 is
absent, and guard the devfreq helper paths against a missing devfreq
instance.

This keeps devfreq enabled for existing platforms while allowing v15 AM
systems to probe without a local devfreq setup.

Signed-off-by: Karunika Choo <karunika.choo@xxxxxxx>
---
 drivers/gpu/drm/panthor/panthor_devfreq.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c
index 2249b41ca4af..c3252ce54437 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.c
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.c
@@ -148,6 +148,9 @@ int panthor_devfreq_init(struct panthor_device *ptdev)
 	unsigned long freq = ULONG_MAX;
 	int ret;
 
+	if (!device_property_read_bool(ptdev->base.dev, "operating-points-v2"))
+		return 0;
+
 	pdevfreq = drmm_kzalloc(&ptdev->base, sizeof(*ptdev->devfreq), GFP_KERNEL);
 	if (!pdevfreq)
 		return -ENOMEM;
@@ -267,7 +270,7 @@ void panthor_devfreq_resume(struct panthor_device *ptdev)
 {
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 
-	if (!pdevfreq->devfreq)
+	if (!pdevfreq || !pdevfreq->devfreq)
 		return;
 
 	panthor_devfreq_reset(pdevfreq);
@@ -279,7 +282,7 @@ void panthor_devfreq_suspend(struct panthor_device *ptdev)
 {
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 
-	if (!pdevfreq->devfreq)
+	if (!pdevfreq || !pdevfreq->devfreq)
 		return;
 
 	drm_WARN_ON(&ptdev->base, devfreq_suspend_device(pdevfreq->devfreq));
@@ -290,7 +293,7 @@ void panthor_devfreq_record_busy(struct panthor_device *ptdev)
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 	unsigned long irqflags;
 
-	if (!pdevfreq->devfreq)
+	if (!pdevfreq || !pdevfreq->devfreq)
 		return;
 
 	spin_lock_irqsave(&pdevfreq->lock, irqflags);
@@ -306,7 +309,7 @@ void panthor_devfreq_record_idle(struct panthor_device *ptdev)
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 	unsigned long irqflags;
 
-	if (!pdevfreq->devfreq)
+	if (!pdevfreq || !pdevfreq->devfreq)
 		return;
 
 	spin_lock_irqsave(&pdevfreq->lock, irqflags);
@@ -323,7 +326,7 @@ unsigned long panthor_devfreq_get_freq(struct panthor_device *ptdev)
 	unsigned long freq = 0;
 	int ret;
 
-	if (!pdevfreq->devfreq)
+	if (!pdevfreq || !pdevfreq->devfreq)
 		return 0;
 
 	ret = pdevfreq->devfreq->profile->get_cur_freq(ptdev->base.dev, &freq);
-- 
2.43.0