[PATCH v1 0/4] Add T-Head TH1520 VO clock support for LicheePi 4A GPU enablement

[Michal Wilczynski]

This is a subset of a larger patch series enabling the Imagination BXM-4-64 GPU
on the LicheePi 4A board, which is powered by the T-HEAD TH1520 SoC. While the
full series includes power-domain, reset, and firmware changes, this part
focuses solely on the clock subsystem needed for the GPU and other VO (video
output) blocks. By merging these clock patches independently, we prepare the
groundwork for future GPU integration via the `drm/imagination` driver.

The T-HEAD TH1520 SoC features multiple clock controllers. Initially, only the
AP clock controller was supported upstream. The patches below add support for
the VO (video output) clock controller, which manages GPU-related gates, HDMI,
and other multimedia clocks. Additionally, they introduce a mechanism to
provide no-op operations for the GPU's "mem" clock gate (documented as
“Reserved” in the hardware manual) and coordinate the GPU CLKGEN reset in the
clock driver.

Bigger series cover letter:

https://lore.kernel.org/all/20250219140239.1378758-1-m.wilczynski@samsung.com/

Michal Wilczynski (4):
  dt-bindings: clock: thead: Add TH1520 VO clock controller
  clk: thead: Add clock support for VO subsystem in T-Head TH1520 SoC
  clk: thead: Add support for custom ops in CCU_GATE_CLK_OPS macro
  clk: thead: Add GPU clock gate control with CLKGEN reset support

 .../bindings/clock/thead,th1520-clk-ap.yaml   |  33 +-
 drivers/clk/thead/clk-th1520-ap.c             | 298 ++++++++++++++++--
 .../dt-bindings/clock/thead,th1520-clk-ap.h   |  34 ++
 3 files changed, 334 insertions(+), 31 deletions(-)

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2.34.1