On Mon, Sep 26, 2022 at 4:36 PM AngeloGioacchino Del Regno
[off-list ref] wrote:

Il 26/09/22 05:27, Chen-Yu Tsai ha scritto:

quoted

On Thu, Sep 15, 2022 at 3:25 PM AngeloGioacchino Del Regno
[off-list ref] wrote:

quoted

The MFG_BG3D is a gate to enable/disable clock output to the GPU,
but the actual output is decided by multiple muxes; in particular:
mfg_ck_fast_ref muxes between "slow" (top_mfg_core_tmp) and
"fast" (MFGPLL) clock, while top_mfg_core_tmp muxes between the
26MHz clock and various system PLLs.

This also implies that "top_mfg_core_tmp" is a parent of the
"mfg_ck_fast_ref" mux (and not vice-versa), so reparent the

I don't see where this was the case though? I think what you meant
was that the direct parent for "mfg_bg3d" is "mfg_ck_fast_ref, not
"top_mfg_core_tmp"?

MFG_BG3D's direct parent is mfg_ck_fast_ref - yes - but in the commit message
I am explaining how the clock tree for MFG_BG3D really is and, in particular,
I'm then explaining that:
* parenting MFG_BG3D to "top_mfg_core_tmp" is wrong; because
* "top_mfg_core_tmp" is a parent of "mfg_ck_fast_ref" (not the other way around).

So, the question in your comment is addressed just a little later....

quoted

quoted

MFG_BG3D gate to the latter and add the CLK_SET_RATE_PARENT

...here, where I say "reparent MFG_BG3D to the latter", where "the latter" is,
exactly "mfg_ck_fast_ref".

I hope you now understand what I am trying to communicate :-)

However, if even after that you still think that the commit description should
be rewritten in some less tangled and/or more understandable way, I definitely
can do that.

Please confirm :-)

I think

    This also implies that "top_mfg_core_tmp" is a parent of the
    "mfg_ck_fast_ref" mux (and not vice-versa)

actually confused me.

Maybe just say

    The clock gate comes after all the muxes, so its parent is
    mfg_ck_fast_ref, not top_mfg_core_tmp. Reparent mfg_bg3d to
    the latter to match the hardware ...

Since you are fixing the topology, could you also add a fixes tag?


Thanks
ChenYu

quoted

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flag to it: this way we ensure propagating rate changes that
are requested on MFG_BG3D along its entire clock tree.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Otherwise,

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>

quoted

---
  drivers/clk/mediatek/clk-mt8195-mfg.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mt8195-mfg.c b/drivers/clk/mediatek/clk-mt8195-mfg.c
index 9411c556a5a9..c94cb71bd9b9 100644
--- a/drivers/clk/mediatek/clk-mt8195-mfg.c
+++ b/drivers/clk/mediatek/clk-mt8195-mfg.c

@@ -17,10 +17,12 @@ static const struct mtk_gate_regs mfg_cg_regs = {
  };

  #define GATE_MFG(_id, _name, _parent, _shift)                  \
-       GATE_MTK(_id, _name, _parent, &mfg_cg_regs, _shift, &mtk_clk_gate_ops_setclr)
+       GATE_MTK_FLAGS(_id, _name, _parent, &mfg_cg_regs,       \
+                      _shift, &mtk_clk_gate_ops_setclr,        \
+                      CLK_SET_RATE_PARENT)

  static const struct mtk_gate mfg_clks[] = {
-       GATE_MFG(CLK_MFG_BG3D, "mfg_bg3d", "top_mfg_core_tmp", 0),
+       GATE_MFG(CLK_MFG_BG3D, "mfg_bg3d", "mfg_ck_fast_ref", 0),
  };

  static const struct mtk_clk_desc mfg_desc = {
--

2.37.2