linux-kernel - Re: [PATCH V2 5/5] i3c: master: svc: add runtime pm support

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Date:   Fri, 16 Jul 2021 09:59:58 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Clark Wang <xiaoning.wang@....com>
Cc:     conor.culhane@...vaco.com, alexandre.belloni@...tlin.com,
        linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 5/5] i3c: master: svc: add runtime pm support

Hi Clark,


> @@ -1431,7 +1502,7 @@ static int svc_i3c_master_probe(struct platform_device *pdev)
>  					 GFP_KERNEL);
>  	if (!master->ibi.slots) {
>  		ret = -ENOMEM;
> -		goto err_disable_sclk;
> +		goto rpm_disable;
>  	}
>  
>  	platform_set_drvdata(pdev, master);
> @@ -1442,18 +1513,17 @@ static int svc_i3c_master_probe(struct platform_device *pdev)
>  	ret = i3c_master_register(&master->base, &pdev->dev,
>  				  &svc_i3c_master_ops, false);
>  	if (ret)
> -		goto err_disable_sclk;
> +		goto rpm_disable;
>  
> -	return 0;
> -
> -err_disable_sclk:
> -	clk_disable_unprepare(master->sclk);
> +	pm_runtime_mark_last_busy(&pdev->dev);
> +	pm_runtime_put_autosuspend(&pdev->dev);
>  
> -err_disable_fclk:
> -	clk_disable_unprepare(master->fclk);
> +	return 0;
>  
> -err_disable_pclk:
> -	clk_disable_unprepare(master->pclk);

It's not clear to me why you drop the disable_*clk labels to move them
back in place? I would rather prefer to keep a clean error path.

> +rpm_disable:
> +	pm_runtime_dont_use_autosuspend(&pdev->dev);
> +	pm_runtime_put_sync(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
>  
>  	return ret;
>  }
> @@ -1467,13 +1537,57 @@ static int svc_i3c_master_remove(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	pm_runtime_dont_use_autosuspend(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused svc_i3c_runtime_suspend(struct device *dev)
> +{
> +	struct svc_i3c_master *master = dev_get_drvdata(dev);
> +
>  	clk_disable_unprepare(master->pclk);
>  	clk_disable_unprepare(master->fclk);
>  	clk_disable_unprepare(master->sclk);
> +	pinctrl_pm_select_sleep_state(dev);
>  
>  	return 0;
>  }
>  
> +static int __maybe_unused svc_i3c_runtime_resume(struct device *dev)
> +{
> +	struct svc_i3c_master *master = dev_get_drvdata(dev);
> +	int ret = 0;
> +
> +	pinctrl_pm_select_default_state(dev);
> +	ret = clk_prepare_enable(master->pclk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(master->fclk);
> +	if (ret) {
> +		clk_disable_unprepare(master->pclk);
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(master->sclk);
> +	if (ret) {
> +		clk_disable_unprepare(master->pclk);
> +		clk_disable_unprepare(master->fclk);
> +		return ret;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops svc_i3c_pm_ops = {
> +	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				      pm_runtime_force_resume)
> +	SET_RUNTIME_PM_OPS(svc_i3c_runtime_suspend,
> +			   svc_i3c_runtime_resume, NULL)
> +};
> +
>  static const struct of_device_id svc_i3c_master_of_match_tbl[] = {
>  	{ .compatible = "silvaco,i3c-master" },
>  	{ /* sentinel */ },
> @@ -1485,6 +1599,7 @@ static struct platform_driver svc_i3c_master = {
>  	.driver = {
>  		.name = "silvaco-i3c-master",
>  		.of_match_table = svc_i3c_master_of_match_tbl,
> +		.pm = &svc_i3c_pm_ops,
>  	},
>  };
>  module_platform_driver(svc_i3c_master);

Thanks,
Miquèl