Re: [PATCH v1 2/2] drm/panthor: treat sram as mandatory except mt8196
From: Boris Brezillon <boris.brezillon@collabora.com>
Date: 2026-02-16 09:37:51
Also in:
dri-devel, linux-mediatek, lkml
On Sun, 15 Feb 2026 13:02:51 +0300 Onur Özkan [off-list ref] wrote:
quoted hunk ↗ jump to hunk
If sram-supply is missing, Panthor falls back to a dummy regulator with a warning. This implicit behavior hides missing DT wiring behind regulator core fallback. Make SRAM handling explicit: require sram-supply for all Panthor compatibles except mt8196-mali where GPU supplies are intentionally managed outside Panthor and DT does not model sram-supply for that compatible. This keeps DT power modeling explicit and avoids relying on dummy-regulator fallback. Link: https://lore.kernel.org/all/20260213155937.6af75786@nimda/ (local) Signed-off-by: Onur Özkan <work@onurozkan.dev> --- drivers/gpu/drm/panthor/panthor_devfreq.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c index 2249b41ca4af..5f6075f18fe3 100644 --- a/drivers/gpu/drm/panthor/panthor_devfreq.c +++ b/drivers/gpu/drm/panthor/panthor_devfreq.c@@ -206,12 +206,17 @@ int panthor_devfreq_init(struct panthor_device *ptdev) * But without knowing if it's beneficial or not (in term of power * consumption), or how much it slows down the suspend/resume steps, * let's just keep regulators enabled for the device lifetime. + * + * Treat sram-supply as mandatory except for mt8196-mali. It manages + * SRAM outside Panthor so this driver must not require direct control + * over it. */ - ret = devm_regulator_get_enable_optional(dev, "sram"); - if (ret && ret != -ENODEV) { - if (ret != -EPROBE_DEFER) + if (!of_device_is_compatible(dev->of_node, "mediatek,mt8196-mali")) {
Rather than checking for specific compats here, let's go for a dont_need_sram_supply bool in panthor_soc_data.
+ ret = devm_regulator_get_enable_optional(dev, "sram");
If we assume SRAM supply is mandatory, should this be devm_regulator_get_enable() instead?
+ if (ret) {
DRM_DEV_ERROR(dev, "Couldn't retrieve/enable sram supply\n");
- return ret;
+ return ret;
+ }
}
opp = devfreq_recommended_opp(dev, &cur_freq, 0);