linux-kernel - Re: [PATCH v2 1/3] clk: qcom: branch: Extend invert logic for branch2 mem clocks

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Message-ID: <ecnfaig4uqlgvvhcadh6pofe7vmlx274gtaabmop6w4gggtjkw@ry3pudcp3hx4>
Date: Sat, 30 Aug 2025 03:17:37 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Taniya Das <taniya.das@....qualcomm.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Ajit Pandey <quic_ajipan@...cinc.com>,
        Imran Shaik <quic_imrashai@...cinc.com>,
        Jagadeesh Kona <quic_jkona@...cinc.com>, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2 1/3] clk: qcom: branch: Extend invert logic for
 branch2 mem clocks

On Fri, Aug 29, 2025 at 03:45:17PM +0530, Taniya Das wrote:
> Some clock branches require inverted logic for memory gating, where
> disabling the memory involves setting a bit and enabling it involves
> clearing the same bit. This behavior differs from the standard approach
> memory branch clocks ops where enabling typically sets the bit.
> 
> Introducing the mem_enable_invert to allow conditional handling of
> these sequences of the inverted control logic for memory operations
> required on those memory clock branches.
> 
> Signed-off-by: Taniya Das <taniya.das@....qualcomm.com>
> ---
>  drivers/clk/qcom/clk-branch.c | 14 +++++++++++---
>  drivers/clk/qcom/clk-branch.h |  4 ++++
>  2 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
> index 0f10090d4ae681babbdbbb1b6c68ffe77af7a784..90da1c94b4736f65c87aec92303d511c4aa9a173 100644
> --- a/drivers/clk/qcom/clk-branch.c
> +++ b/drivers/clk/qcom/clk-branch.c
> @@ -142,8 +142,12 @@ static int clk_branch2_mem_enable(struct clk_hw *hw)
>  	u32 val;
>  	int ret;
>  
> -	regmap_update_bits(branch.clkr.regmap, mem_br->mem_enable_reg,
> -			   mem_br->mem_enable_ack_mask, mem_br->mem_enable_ack_mask);
> +	if (mem_br->mem_enable_invert)
> +		regmap_update_bits(branch.clkr.regmap, mem_br->mem_enable_reg,
> +				  mem_br->mem_enable_mask, 0);
> +	else
> +		regmap_update_bits(branch.clkr.regmap, mem_br->mem_enable_reg,
> +				  mem_br->mem_enable_ack_mask, mem_br->mem_enable_ack_mask);

Please check that your lines are properly indented.

>  
>  	ret = regmap_read_poll_timeout(branch.clkr.regmap, mem_br->mem_ack_reg,
>  				       val, val & mem_br->mem_enable_ack_mask, 0, 200);
> @@ -159,7 +163,11 @@ static void clk_branch2_mem_disable(struct clk_hw *hw)
>  {
>  	struct clk_mem_branch *mem_br = to_clk_mem_branch(hw);
>  
> -	regmap_update_bits(mem_br->branch.clkr.regmap, mem_br->mem_enable_reg,
> +	if (mem_br->mem_enable_invert)
> +		regmap_update_bits(mem_br->branch.clkr.regmap, mem_br->mem_enable_reg,
> +			   mem_br->mem_enable_mask, mem_br->mem_enable_mask);

This creates assymmetry. The drivers uses mem_enable_mask in one case
and mem_enable_ack_mask in another.

> +	else
> +		regmap_update_bits(mem_br->branch.clkr.regmap, mem_br->mem_enable_reg,
>  			   mem_br->mem_enable_ack_mask, 0);

And here.

>  
>  	return clk_branch2_disable(hw);
> diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
> index 292756435f53648640717734af198442a315272e..6bc2ba2b5350554005b7f0c84f933580b7582fc7 100644
> --- a/drivers/clk/qcom/clk-branch.h
> +++ b/drivers/clk/qcom/clk-branch.h
> @@ -44,6 +44,8 @@ struct clk_branch {
>   * @mem_enable_reg: branch clock memory gating register
>   * @mem_ack_reg: branch clock memory ack register
>   * @mem_enable_ack_mask: branch clock memory enable and ack field in @mem_ack_reg
> + * @mem_enable_mask: branch clock memory enable mask
> + * @mem_enable_invert: branch clock memory enable and disable has invert logic
>   * @branch: branch clock gating handle
>   *
>   * Clock which can gate its memories.
> @@ -52,6 +54,8 @@ struct clk_mem_branch {
>  	u32	mem_enable_reg;
>  	u32	mem_ack_reg;
>  	u32	mem_enable_ack_mask;
> +	u32	mem_enable_mask;
> +	bool	mem_enable_invert;
>  	struct clk_branch branch;
>  };
>  
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry