linux-kernel - Re: [PATCH V2 3/6] clk: qcom: clk-alpha-pll: Remove explicit CAL

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Message-ID: <6e1d098d-03b9-aa63-a0bf-6cf748a0db0d@linaro.org>
Date:   Fri, 26 May 2023 11:33:21 +0200
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Jagadeesh Kona <quic_jkona@...cinc.com>,
        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:     Bjorn Andersson <andersson@...nel.org>,
        Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>,
        Vinod Koul <vkoul@...nel.org>, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Taniya Das <quic_tdas@...cinc.com>,
        Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
        Imran Shaik <quic_imrashai@...cinc.com>,
        Ajit Pandey <quic_ajipan@...cinc.com>
Subject: Re: [PATCH V2 3/6] clk: qcom: clk-alpha-pll: Remove explicit CAL_L
 configuration for EVO PLL



On 25.05.2023 19:21, Jagadeesh Kona wrote:
> In lucid evo pll, the CAL_L field is part of L value register itself, and
> the l value configuration passed from clock controller driver includes
> CAL_L and L values as well. Hence remove explicit configuration of CAL_L
> for evo pll.
> 
> Fixes: 260e36606a03 ("clk: qcom: clk-alpha-pll: add Lucid EVO PLL configuration interfaces")
> Signed-off-by: Taniya Das <quic_tdas@...cinc.com>
> Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
> ---
Oh that isn't obvious at first sight, nice find!

I'd suggest a different solution though:

#define LUCID_EVO_PLL_L_LVAL	GENMASK(..
#define LUCID_EVO_PLL_L_CAL_L	GENMASK(..

lval = FIELD_PREP(LUCID_EVO_PLL_L_LVAL, config->l) |
       FIELD_PREP(LUCID_EVO_PLL_L_CAL_L, config->cal_l);

This would make the separation between the two parts more explicit

however

config->l would then represent the L value and not the end value
written to the L register

Up to you, whichever you find saner!

Konrad

> Changes since V1:
>  - Newly added.
> 
>  drivers/clk/qcom/clk-alpha-pll.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> index f81c7c561352..68a80395997b 100644
> --- a/drivers/clk/qcom/clk-alpha-pll.c
> +++ b/drivers/clk/qcom/clk-alpha-pll.c
> @@ -270,7 +270,6 @@ EXPORT_SYMBOL_GPL(clk_alpha_pll_regs);
>  #define LUCID_EVO_PCAL_NOT_DONE		BIT(8)
>  #define LUCID_EVO_ENABLE_VOTE_RUN       BIT(25)
>  #define LUCID_EVO_PLL_L_VAL_MASK        GENMASK(15, 0)
> -#define LUCID_EVO_PLL_CAL_L_VAL_SHIFT	16
>  
>  /* ZONDA PLL specific */
>  #define ZONDA_PLL_OUT_MASK	0xf
> @@ -2084,10 +2083,7 @@ EXPORT_SYMBOL_GPL(clk_alpha_pll_zonda_ops);
>  void clk_lucid_evo_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
>  				 const struct alpha_pll_config *config)
>  {
> -	u32 lval = config->l;
> -
> -	lval |= TRION_PLL_CAL_VAL << LUCID_EVO_PLL_CAL_L_VAL_SHIFT;
> -	clk_alpha_pll_write_config(regmap, PLL_L_VAL(pll), lval);
> +	clk_alpha_pll_write_config(regmap, PLL_L_VAL(pll), config->l);
>  	clk_alpha_pll_write_config(regmap, PLL_ALPHA_VAL(pll), config->alpha);
>  	clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL(pll), config->config_ctl_val);
>  	clk_alpha_pll_write_config(regmap, PLL_CONFIG_CTL_U(pll), config->config_ctl_hi_val);