linux-kernel - Re: [PATCH 1/2] clk: qcom: clk-krait: switch to .determine

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Date:   Sun, 12 Feb 2023 10:09:29 +0100
From:   Christian Marangi <ansuelsmth@...il.com>
To:     Luca Weiss <luca@...tu.xyz>
Cc:     ~postmarketos/upstreaming@...ts.sr.ht, phone-devel@...r.kernel.org,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] clk: qcom: clk-krait: switch to .determine_rate

On Sun, Feb 12, 2023 at 03:11:08PM +0100, Luca Weiss wrote:
> .determine_rate is meant to replace .round_rate. The former comes with a
> benefit which is especially relevant on 32-bit systems: since
> .determine_rate uses an "unsigned long" (compared to a "signed long"
> which is used by .round_rate) the maximum value on 32-bit systems
> increases from 2^31 (or approx. 2.14GHz) to 2^32 (or approx. 4.29GHz).
> 
> Signed-off-by: Luca Weiss <luca@...tu.xyz>

Hi, found time to test this on ipq806x and seems to work correctly by
scaling to each freq and checking the hfpll reported freq.

Tested-by: Christian Marangi <ansuelsmth@...il.com>

> ---
>  drivers/clk/qcom/clk-krait.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
> index 293a9dfa7151..f5ce403e1e27 100644
> --- a/drivers/clk/qcom/clk-krait.c
> +++ b/drivers/clk/qcom/clk-krait.c
> @@ -97,11 +97,11 @@ const struct clk_ops krait_mux_clk_ops = {
>  EXPORT_SYMBOL_GPL(krait_mux_clk_ops);
>  
>  /* The divider can divide by 2, 4, 6 and 8. But we only really need div-2. */
> -static long krait_div2_round_rate(struct clk_hw *hw, unsigned long rate,
> -				  unsigned long *parent_rate)
> +static int krait_div2_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
>  {
> -	*parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), rate * 2);
> -	return DIV_ROUND_UP(*parent_rate, 2);
> +	req->best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), req->rate * 2);
> +	req->rate = DIV_ROUND_UP(req->best_parent_rate, 2);
> +	return 0;
>  }
>  
>  static int krait_div2_set_rate(struct clk_hw *hw, unsigned long rate,
> @@ -142,7 +142,7 @@ krait_div2_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
>  }
>  
>  const struct clk_ops krait_div2_clk_ops = {
> -	.round_rate = krait_div2_round_rate,
> +	.determine_rate = krait_div2_determine_rate,
>  	.set_rate = krait_div2_set_rate,
>  	.recalc_rate = krait_div2_recalc_rate,
>  };
> 
> -- 
> 2.39.1
> 

-- 
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