linux-kernel - Re: [PATCH v2] clk: qcom: lpasscc: Re-configure the PLL in case lost

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Date:   Wed, 14 Oct 2020 22:51:30 +0530
From:   Taniya Das <tdas@...eaurora.org>
To:     Douglas Anderson <dianders@...omium.org>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        linux-soc@...r.kernel.org, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] clk: qcom: lpasscc: Re-configure the PLL in case lost

Thanks Doug for the patch.

On 10/14/2020 9:28 PM, Douglas Anderson wrote:
> From: Taniya Das <tdas@...eaurora.org>
> 
> In the case where the PLL configuration is lost, then the pm runtime
> resume will reconfigure before usage.
> 
> Fixes: edab812d802d ("clk: qcom: lpass: Add support for LPASS clock controller for SC7180")
> Signed-off-by: Taniya Das <tdas@...eaurora.org>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> ---
> I took the liberty of fixing my own nits that I had with Taniya's
> patch, AKA:
> 
> https://lore.kernel.org/r/1602614008-2421-2-git-send-email-tdas@codeaurora.org
> 
> Changes in v2:
> - Don't needlessly have a 2nd copy of dev_pm_ops and jam it in.
> - Check the return value of pm_clk_resume()
> - l_val should be unsigned int.
> 
>   drivers/clk/qcom/lpasscorecc-sc7180.c | 23 ++++++++++++++++++++++-
>   1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/qcom/lpasscorecc-sc7180.c b/drivers/clk/qcom/lpasscorecc-sc7180.c
> index 228d08f5d26f..ee23eb5b9bf2 100644
> --- a/drivers/clk/qcom/lpasscorecc-sc7180.c
> +++ b/drivers/clk/qcom/lpasscorecc-sc7180.c
> @@ -356,6 +356,25 @@ static const struct qcom_cc_desc lpass_audio_hm_sc7180_desc = {
>   	.num_gdscs = ARRAY_SIZE(lpass_audio_hm_sc7180_gdscs),
>   };
>   
> +static int lpass_core_cc_pm_clk_resume(struct device *dev)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +	unsigned int l_val;
> +	int ret;
> +
> +	ret = pm_clk_resume(dev);
> +	if (ret)
> +		return ret;
> +
> +	/* Read PLL_L_VAL */
> +	regmap_read(regmap, 0x1004, &l_val);
> +	if (!l_val)
> +		clk_fabia_pll_configure(&lpass_lpaaudio_dig_pll, regmap,
> +				&lpass_lpaaudio_dig_pll_config);
> +
> +	return 0;
> +}
> +
>   static int lpass_core_cc_sc7180_probe(struct platform_device *pdev)
>   {
>   	const struct qcom_cc_desc *desc;
> @@ -373,6 +392,8 @@ static int lpass_core_cc_sc7180_probe(struct platform_device *pdev)
>   	if (IS_ERR(regmap))
>   		return PTR_ERR(regmap);
>   
> +	dev_set_drvdata(&pdev->dev, regmap);
> +
>   	/*
>   	 * Keep the CLK always-ON
>   	 * LPASS_AUDIO_CORE_SYSNOC_SWAY_CORE_CLK
> @@ -449,7 +470,7 @@ static int lpass_core_sc7180_probe(struct platform_device *pdev)
>   }
>   
>   static const struct dev_pm_ops lpass_core_cc_pm_ops = {
> -	SET_RUNTIME_PM_OPS(pm_clk_suspend, pm_clk_resume, NULL)
> +	SET_RUNTIME_PM_OPS(pm_clk_suspend, lpass_core_cc_pm_clk_resume, NULL)

There are two devices and "lpass_hm_core" and the PLL is not part of the 
HM_CORE, thus was the reason to separate out the pm_ops.

>   };
>   
>   static struct platform_driver lpass_core_cc_sc7180_driver = {
> 

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