linux-kernel - Re: [PATCH] clk: qcom: gcc-qcs615: Fix gcc_sdcc2_apps_clk

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Message-ID: <qqtqberlztcqhs7rv32beec2w6soebpgxovo54omfqijt2nct3@odcwbd5idqnl>
Date: Tue, 12 Aug 2025 11:16:19 -0500
From: Bjorn Andersson <andersson@...nel.org>
To: Taniya Das <taniya.das@....qualcomm.com>
Cc: Richa Bharti <Richa.Bharti@...mens.com>, mturquette@...libre.com, 
	sboyd@...nel.org, linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org, 
	linux-kernel@...r.kernel.org, srikanth.krishnakar@...mens.com, cedric.hombourger@...mens.com
Subject: Re: [PATCH] clk: qcom: gcc-qcs615: Fix gcc_sdcc2_apps_clk_src

On Tue, Aug 12, 2025 at 12:34:02PM +0530, Taniya Das wrote:
> 
> 
> On 8/12/2025 9:20 AM, Bjorn Andersson wrote:
> > On Tue, Jul 29, 2025 at 04:08:21PM +0530, Taniya Das wrote:
> >>
> >>
> >> On 7/29/2025 3:19 PM, Richa Bharti wrote:
> >>> On QCS615, we see the same issue as reported on SM8250 and SM6350:
> >>> "gcc_sdcc2_apps_clk_src: rcg didn't update its configuration" during boot.
> >>> This is due to GPLL7 not being enabled by default as a parent clock.
> >>>
> >>> Setting `.flags = CLK_OPS_PARENT_ENABLE` ensures that the parent (GPLL7)
> >>> gets prepared and enabled when switching to it, fixing the warning.
> >>>
> >>> Fixes: 39d6dcf67fe9 ("clk: qcom: gcc: Add support for QCS615 GCC clocks")
> >>> Signed-off-by: Richa Bharti <Richa.Bharti@...mens.com>
> > 
> > Thank you Richa for your patch!
> > 
> >>> ---
> >>> This change is similar to upstream commits:
> >>> - SM8250: 783cb693828c ("clk: qcom: gcc-sm8250: Fix
> >>>   gcc_sdcc2_apps_clk_src")
> >>> - SM6350: df04d166d1f3 ("clk: qcom: gcc-sm6350: Fix
> >>>   gcc_sdcc2_apps_clk_src")
> >>> ---
> >>>  drivers/clk/qcom/gcc-qcs615.c | 1 +
> >>>  1 file changed, 1 insertion(+)
> >>>
> >>> diff --git a/drivers/clk/qcom/gcc-qcs615.c b/drivers/clk/qcom/gcc-qcs615.c
> >>> index 9695446bc2a3..b281f0dfe165 100644
> >>> --- a/drivers/clk/qcom/gcc-qcs615.c
> >>> +++ b/drivers/clk/qcom/gcc-qcs615.c
> >>> @@ -830,6 +830,7 @@ static struct clk_rcg2 gcc_sdcc2_apps_clk_src = {
> >>>  		.name = "gcc_sdcc2_apps_clk_src",
> >>>  		.parent_data = gcc_parent_data_8,
> >>>  		.num_parents = ARRAY_SIZE(gcc_parent_data_8),
> >>> +		.flags = CLK_OPS_PARENT_ENABLE,
> >>
> >> This is not the correct way to fix it just because SM8250 and SM6350
> >> uses this ops.
> >>
> >> We are testing the right fix internally and will be posting.
> >>
> > 
> > Please use such opportunities to educate us, rather than just tell us to
> > blindly wait for something (at least share your thoughts/hypothesis).
> > 
> 
> Sure, Bjorn.
> 
> https://patchwork.kernel.org/project/linux-clk/patch/20250804-sdcc_rcg2_shared_ops-v1-1-41f989e8cbb1@oss.qualcomm.com/
> 
> The RCG configuration goes to a bad state because the current floor_ops
> tries to update the rcg configuration even if the clock is not enabled.
> 
> The correct fix is to ensure we do that when the clock is actually
> enabled which is brought it by the shared_floor_ops.
> 

Excellent, thanks for the explanation.

> Please let me know if you still have any queries.
> 

No concerns, this is exactly the kind of transparency I was looking for.

Many thanks for the quick reply,
Bjorn

> > Regards,
> > Bjorn
> > 
> >>>  		.ops = &clk_rcg2_floor_ops,
> >>>  	},
> >>>  };
> >>
> >> -- 
> >> Thanks,
> >> Taniya Das
> >>
> 
> -- 
> Thanks,
> Taniya Das
>