Re: [PATCH 3/3] clk: qcom: add MSM8x60 MMCC driver

[Linus Walleij]

On Sat, May 30, 2026 at 3:58 PM Herman van Hazendonk
<github.com@xxxxxxxxxx> wrote:

> Add a clock driver for the Multimedia Clock Controller (MMCC) on the
> MSM8x60 family (MSM8260/MSM8660/APQ8060) - the Scorpion-class
> generation that preceded MSM8960's Krait CPUs.
>
> The MMCC layout on MSM8x60 differs from MSM8960 in several ways that
> make a separate driver cleaner than parameterising mmcc-msm8960.c:
>
>   - the pix_rdi mux requires a custom set_parent op that temporarily
>     enables both parents during the glitch-free transition;
>   - the IJPEG GDSC requires releasing AXI, AHB and CORE resets;
>   - several rate-source pairs (MDP pixel, GFX2D/3D) only exist on
>     8x60 (e.g. PLL2-derived 228571000/266667000 for graphics);
>   - the camera CSI / VFE / JPEG / VPE / ROT clock topology lacks the
>     later 8960 reorganisation.
>
> Used on the HP TouchPad (Tenderloin) for graphics (Adreno A220),
> display (MDP4), camera (CSI/VFE), JPEG (Gemini), VIDC, VPE and
> rotator. Reset IDs are exposed via a separate header so consumers
> can reset the GDSCs and individual blocks.
>
> Signed-off-by: Herman van Hazendonk <github.com@xxxxxxxxxx>

I spent some time looking at this driver and comparing it to my
earlier attempt at the same, it's basically a better and more complete
version of what I was hacking on so naturally I'm a big fan of this
driver.

I can't find anything more to add, except perhaps a top-level
comment that in some documentation PLL2 is called called
MM_PLL1 and PLL3 is called MM_PLL2 which can be confusing,
so it's good to mention this somewhere.

Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>

Yours,
Linus Walleij