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

From: Taniya Das <tdas@codeaurora.org>
To: Douglas Anderson <dianders@chromium.org>,
	Stephen Boyd <sboyd@kernel.org>
Cc: David Brown <david.brown@linaro.org>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	linux-soc@vger.kernel.org, Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] clk: qcom: lpasscc: Re-configure the PLL in case lost
Date: Wed, 14 Oct 2020 22:51:30 +0530	[thread overview]
Message-ID: <711a8178-dcf7-d541-a468-ac34d6d14bb1@codeaurora.org> (raw)
In-Reply-To: <20201014085758.v2.1.Id0cc5d859e2422082a29a7909658932c857f5a81@changeid>

Thanks Doug for the patch.

On 10/14/2020 9:28 PM, Douglas Anderson wrote:
> From: Taniya Das <tdas@codeaurora.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@codeaurora.org>
> Signed-off-by: Douglas Anderson <dianders@chromium.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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