Re: [PATCH 3/3] coresight-tnoc: Add runtime PM support for Interconnect TNOC

[Leo Yan <leo.yan@arm.com>]

On Fri, Aug 15, 2025 at 06:18:14AM -0700, Yuanfang Zhang wrote:
> This patch adds runtime power management support for platform-based
> CoreSight Interconnect TNOC (ITNOC) devices. It introduces suspend and
> resume callbacks to manage the APB clock (`pclk`) during device runtime
> transitions.
> 
> Signed-off-by: Yuanfang Zhang <yuanfang.zhang@oss.qualcomm.com>
> ---
>  drivers/hwtracing/coresight/coresight-tnoc.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-tnoc.c b/drivers/hwtracing/coresight/coresight-tnoc.c
> index aa6f48d838c00d71eff22c18e34e00b93755fd82..f12a1698824bc678545319a3f482fd27e67a7352 100644
> --- a/drivers/hwtracing/coresight/coresight-tnoc.c
> +++ b/drivers/hwtracing/coresight/coresight-tnoc.c
> @@ -270,6 +270,31 @@ static void itnoc_remove(struct platform_device *pdev)
>  	pm_runtime_disable(&pdev->dev);
>  }
>  
> +#ifdef CONFIG_PM
> +static int itnoc_runtime_suspend(struct device *dev)
> +{
> +	struct trace_noc_drvdata *drvdata = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(drvdata->pclk);
> +
> +	return 0;
> +}
> +
> +static int itnoc_runtime_resume(struct device *dev)
> +{
> +	struct trace_noc_drvdata *drvdata = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(drvdata->pclk);
> +
> +	return ret;

Here can be simplified:

    return clk_prepare_enable(drvdata->pclk);

> +}
> +#endif
> +
> +static const struct dev_pm_ops itnoc_dev_pm_ops = {
> +	SET_RUNTIME_PM_OPS(itnoc_runtime_suspend, itnoc_runtime_resume, NULL)
> +};
> +
>  static const struct of_device_id itnoc_of_match[] = {
>  	{ .compatible = "qcom,coresight-itnoc" },
>  	{}
> @@ -282,6 +307,7 @@ static struct platform_driver itnoc_driver = {
>  	.driver = {
>  		.name = "coresight-itnoc",
>  		.of_match_table = itnoc_of_match,
> +		.pm = &itnoc_dev_pm_ops,
>  	},
>  };
>  
> 
> -- 
> 2.34.1
> 
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