linux-kernel - Re: [PATCH v2 06/15] clk: qcom: gpucc-sm6115: Unregister critical clocks

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Date:   Wed, 29 Nov 2023 21:14:50 +0000
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v2 06/15] clk: qcom: gpucc-sm6115: Unregister critical
 clocks

On 29/11/2023 18:59, Konrad Dybcio wrote:
> Some clocks need to be always-on, but we don't really do anything
> with them, other than calling enable() once and telling Linux they're
> enabled.
> 
> Unregister them to save a couple of bytes and, perhaps more
> importantly, allow for runtime suspend of the clock controller device,
> as CLK_IS_CRITICAL prevents the latter.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
> ---
>   drivers/clk/qcom/gpucc-sm6115.c | 33 +++------------------------------
>   1 file changed, 3 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/clk/qcom/gpucc-sm6115.c b/drivers/clk/qcom/gpucc-sm6115.c
> index fb71c21c9a89..93a50431aef8 100644
> --- a/drivers/clk/qcom/gpucc-sm6115.c
> +++ b/drivers/clk/qcom/gpucc-sm6115.c
> @@ -234,20 +234,6 @@ static struct clk_rcg2 gpu_cc_gx_gfx3d_clk_src = {
>   	},
>   };
>   
> -static struct clk_branch gpu_cc_ahb_clk = {
> -	.halt_reg = 0x1078,
> -	.halt_check = BRANCH_HALT_DELAY,
> -	.clkr = {
> -		.enable_reg = 0x1078,
> -		.enable_mask = BIT(0),
> -		.hw.init = &(struct clk_init_data){
> -			.name = "gpu_cc_ahb_clk",
> -			.flags = CLK_IS_CRITICAL,
> -			.ops = &clk_branch2_ops,
> -		},
> -	},
> -};
> -
>   static struct clk_branch gpu_cc_crc_ahb_clk = {
>   	.halt_reg = 0x107c,
>   	.halt_check = BRANCH_HALT_DELAY,
> @@ -336,20 +322,6 @@ static struct clk_branch gpu_cc_cxo_clk = {
>   	},
>   };
>   
> -static struct clk_branch gpu_cc_gx_cxo_clk = {
> -	.halt_reg = 0x1060,
> -	.halt_check = BRANCH_HALT_DELAY,
> -	.clkr = {
> -		.enable_reg = 0x1060,
> -		.enable_mask = BIT(0),
> -		.hw.init = &(struct clk_init_data){
> -			.name = "gpu_cc_gx_cxo_clk",
> -			.flags = CLK_IS_CRITICAL,
> -			.ops = &clk_branch2_ops,
> -		},
> -	},
> -};
> -
>   static struct clk_branch gpu_cc_gx_gfx3d_clk = {
>   	.halt_reg = 0x1054,
>   	.halt_check = BRANCH_HALT_SKIP,
> @@ -418,7 +390,6 @@ static struct gdsc gpu_gx_gdsc = {
>   };
>   
>   static struct clk_regmap *gpu_cc_sm6115_clocks[] = {
> -	[GPU_CC_AHB_CLK] = &gpu_cc_ahb_clk.clkr,
>   	[GPU_CC_CRC_AHB_CLK] = &gpu_cc_crc_ahb_clk.clkr,
>   	[GPU_CC_CX_GFX3D_CLK] = &gpu_cc_cx_gfx3d_clk.clkr,
>   	[GPU_CC_CX_GMU_CLK] = &gpu_cc_cx_gmu_clk.clkr,
> @@ -426,7 +397,6 @@ static struct clk_regmap *gpu_cc_sm6115_clocks[] = {
>   	[GPU_CC_CXO_AON_CLK] = &gpu_cc_cxo_aon_clk.clkr,
>   	[GPU_CC_CXO_CLK] = &gpu_cc_cxo_clk.clkr,
>   	[GPU_CC_GMU_CLK_SRC] = &gpu_cc_gmu_clk_src.clkr,
> -	[GPU_CC_GX_CXO_CLK] = &gpu_cc_gx_cxo_clk.clkr,

OTOH.

Seems a pity to remove these clocks - generally for the series I mean - 
from the debug view in /sys/kernel/debug/clk_summary.

In the ideal case we have pm runtime functional without dropping these 
clocks from the view in /sys/kernel/debug/clk_summary.

Certainly I've found that interface useful when launching a real 
product. It might be confusing to _not_ see the always-on clocks 
enumerated there.

---
bod