linux-kernel - Re: [PATCH 1/2] clk: qcom: common: Add support for power-domain attachment

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Message-ID: <8a33c0ff-0c6d-4995-b239-023d2a2c2af5@linaro.org>
Date: Tue, 19 Nov 2024 00:17:06 +0200
From: Vladimir Zapolskiy <vladimir.zapolskiy@...aro.org>
To: Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
 Bjorn Andersson <andersson@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] clk: qcom: common: Add support for power-domain
 attachment

On 11/18/24 04:24, Bryan O'Donoghue wrote:
> Right now we have a plethora of singleton power-domains which power clock
> controllers. These singletons are switched on by core logic when we probe
> the clocks.
> 
> However when multiple power-domains are attached to a clock controller that
> list of power-domains needs to be managed outside of core logic.
> 
> Use dev_pm_domain_attach_list() to automatically hook the list of given
> power-domains in the dtsi for the clock being registered in
> qcom_cc_really_probe().
> 
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
> ---
>   drivers/clk/qcom/common.c | 24 ++++++++++++++++++++++++
>   1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
> index 33cc1f73c69d1f875a193aea0552902268dc8716..b4377fa09f7c0ec8d3c63dfc97d04fbb8cd6e10b 100644
> --- a/drivers/clk/qcom/common.c
> +++ b/drivers/clk/qcom/common.c
> @@ -22,6 +22,7 @@ struct qcom_cc {
>   	struct qcom_reset_controller reset;
>   	struct clk_regmap **rclks;
>   	size_t num_rclks;
> +	struct dev_pm_domain_list *pd_list;
>   };
>   
>   const
> @@ -283,6 +284,25 @@ static int qcom_cc_icc_register(struct device *dev,
>   						     desc->num_icc_hws, icd);
>   }
>   
> +static int qcom_cc_pds_attach(struct device *dev, struct qcom_cc *cc)
> +{
> +	struct dev_pm_domain_attach_data pd_data = {
> +		.pd_names = 0,
> +		.num_pd_names = 0,
> +	};
> +	int ret;
> +
> +	/* Only one power-domain platform framework will hook it up */
> +	if (dev->pm_domain)
> +		return 0;
> +
> +	ret = dev_pm_domain_attach_list(dev, &pd_data, &cc->pd_list);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
>   int qcom_cc_really_probe(struct device *dev,
>   			 const struct qcom_cc_desc *desc, struct regmap *regmap)
>   {
> @@ -299,6 +319,10 @@ int qcom_cc_really_probe(struct device *dev,
>   	if (!cc)
>   		return -ENOMEM;
>   
> +	ret = qcom_cc_pds_attach(dev, cc);
> +	if (ret)
> +		return ret;
> +

	ret = devm_pm_domain_attach_list(dev, NULL, &cc->pd_list);
	if (ret < 0 && ret != -EEXIST)
		return ret;

That's it. No need to introduce a new function, not saying about 20 LoC off.

Next, you have to call dev_pm_domain_detach_list() in your version of the
change on the error paths etc., fortunately this can be easily avoided,
if the resource management flavour of the same function is in use.

>   	reset = &cc->reset;
>   	reset->rcdev.of_node = dev->of_node;
>   	reset->rcdev.ops = &qcom_reset_ops;
> 

--
Best wishes,
Vladimir