[PATCH 0/9] Panfrost: Improve and add MediaTek SoCs support

[Chen-Yu Tsai]

On Wed, Feb 8, 2023 at 6:37 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno at collabora.com> wrote:
>
> This series adds support for new MediaTek SoCs (MT8186/MT8192/MT8195)
> and improves MT8183 support: since the mtk-regulator-coupler driver
> was picked, it is now useless for Panfrost to look for, and manage,
> two regulators (GPU Vcore and GPU SRAM) on MediaTek;
>
> The aforementioned driver will take care of keeping the voltage
> relation (/constraints) of the two regulators on its own when a
> voltage change request is sent to the Vcore, solving the old time
> issue with not working DVFS on Panfrost+MediaTek (due to devfreq
> supporting only single regulator).
>
> In the specific case of MT8183, in order to not break the ABI, it
> was necessary to add a new compatible for enabling DVFS.

Tested on MT8183 Juniper (Kukui-based device), MT8192 Hayato (Asurada-based),
and MT8195 Tomato (Cherry-based).

GPU probed. When running glmark-es2-drm, observed state transitions in
/sys/class/devfreq/13040000.gpu/trans_stat , as well as actual changes to
values for regulators and clocks.

Tested-by: Chen-Yu Tsai <wenst at chromium.org>

Also observed that sometimes when glmark terminated, the GPU would not be
brought down to the lowest OPP.