Hi Elaine,

On 2025-01-25 06:38, Alex Bee wrote:

Hi Elaine,

Am 25.01.25 um 02:15 schrieb Elaine Zhang:

quoted

This reverts commit 1d34b9757523c1ad547bd6d040381f62d74a3189.

RK3228 Only GPLL and CPLL, GPLL is a common clock, does not allow
dclk_vop to change its frequency, CPLL is used by GMAC,
if dclk_vop use CLK_SET_RATE_PARENT and CLK_SET_RATE_NO_REPARENT flags will
affect the GMAC function.

how do you come to this conclusion?

On the RK3228, hdmiphy is the default parent of dclk_vop, a clock that is
not even generated by the CRU but is the output of an external HDMI PHY.
The CLK_SET_RATE_NO_REPARENT flag ensures that the parent of dclk_vop never
changes to sclk_vop_pre (and thus never uses CPLL or GPLL). With
CLK_SET_RATE_PARENT we only ensure that we can use all rates of [0] since
there is no divider between dclk_vop and hdmiphy. Overall it is pretty much
the same situation as for RK3328, which handles these clocks in the same
way (see dclk_lcdc for RK3328).

I came to similar conclusion for v1 of this patch, see [2].

Maybe we should assign clk parent in DT similar to rk3328.dtsi to make
it extra clear that hdmiphy should be used as parent?

  assigned-clocks = <&cru DCLK_VOP>;
  assigned-clock-parents = <&cru SCLK_HDMI_PHY>;

Also for next revert patch you send, please include the patch author in
the recipient list :-)

[2] https://lore.kernel.org/all/d95d317c-5f6e-42bd-94a9-e1a6c7685e2f@kwiboo.se/ (local)

Regards,
Jonas

Regards,
Alex

[0] [1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/phy/rockchip/phy-rockchip-inno-hdmi.c?h=v6.13#n293

quoted

If the client application does not use GMAC and CPLL is free, make this
change on the local branch.

Signed-off-by: Elaine Zhang <redacted>
---
  drivers/clk/rockchip/clk-rk3228.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/rockchip/clk-rk3228.c b/drivers/clk/rockchip/clk-rk3228.c
index ed602c27b624..9c0284607766 100644
--- a/drivers/clk/rockchip/clk-rk3228.c
+++ b/drivers/clk/rockchip/clk-rk3228.c

@@ -409,7 +409,7 @@ static struct rockchip_clk_branch rk3228_clk_branches[] __initdata = {
  			RK2928_CLKSEL_CON(29), 0, 3, DFLAGS),
  	DIV(0, "sclk_vop_pre", "sclk_vop_src", 0,
  			RK2928_CLKSEL_CON(27), 8, 8, DFLAGS),
-	MUX(DCLK_VOP, "dclk_vop", mux_dclk_vop_p, CLK_SET_RATE_PARENT | CLK_SET_RATE_NO_REPARENT,
+	MUX(DCLK_VOP, "dclk_vop", mux_dclk_vop_p, 0,
  			RK2928_CLKSEL_CON(27), 1, 1, MFLAGS),
  
  	FACTOR(0, "xin12m", "xin24m", 0, 1, 2),