[PATCH v4 7/8] drm/panthor: Use existing OPP table if present

Nicolas Frattaroli
2025-09-23T11:41:29Z

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 | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c
index 8903f60c0a3f06313ac2008791c210ff32b6bd52..4ec46a67db7d4331ac31a249e41ee19378cd411e 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;

@@ -152,17 +153,22 @@ 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");
+ 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;
- }
+ return ret;
+ }

- ret = devm_pm_opp_of_add_table(dev);
- if (ret)
- return ret;
+ ret = devm_pm_opp_of_add_table(dev);
+ if (ret)
+ return ret;
+ } else {
+ dev_pm_opp_put_opp_table(t);
+ }

spin_lock_init(&pdevfreq->lock);

--
2.51.0