[0/4] drm/panfrost: Turn off clocks and regulators in PM

Message

AngeloGioacchino Del Regno Oct. 30, 2023, 1:22 p.m. UTC

At least MediaTek platforms are able to get the GPU clocks and regulators
completely off during system suspend, allowing to save a bit of power.

Panfrost is used on more than just MediaTek SoCs and the benefits of this
can be variable across different SoC models and/or different SoCs from
different manufacturers: this means that just adding this ability for all
could result in unexpected issues and breakages on untested SoCs.

For the aforemenetioned reasons, turning off the clocks and/or regulators
was implemented inside of a capabilities barrier that shall be enabled on
a per-SoC basis (in the panfrost_compatible platform data) after testing
of both benefits and feasibility.

In this series, I am adding the ability to switch on/off clocks and
regulators and enabling that on all MediaTek platforms, as I was able
to successfully test that on multiple Chromebooks featuring different
MediaTek SoCs; specifically, I've manually tested on MT8186, MT8192 and
MT8195, while MT8183 got tested only by KernelCI.

Cheers!

AngeloGioacchino Del Regno (4):
  drm/panfrost: Implement ability to turn on/off GPU clocks in suspend
  drm/panfrost: Set clocks on/off during system sleep on MediaTek SoCs
  drm/panfrost: Implement ability to turn on/off regulators in suspend
  drm/panfrost: Set regulators on/off during system sleep on MediaTek
    SoCs

 drivers/gpu/drm/panfrost/panfrost_device.c | 78 ++++++++++++++++++++--
 drivers/gpu/drm/panfrost/panfrost_device.h | 13 ++++
 drivers/gpu/drm/panfrost/panfrost_drv.c    |  3 +
 3 files changed, 90 insertions(+), 4 deletions(-)