linux-kernel - Re: [PATCH] soc: imx8m: Add remove function

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Message-ID: <20241206114130.zt4rkotzbzi3xt5n@pengutronix.de>
Date: Fri, 6 Dec 2024 12:41:30 +0100
From: Marco Felsch <m.felsch@...gutronix.de>
To: "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc: shawnguo@...nel.org, s.hauer@...gutronix.de, marex@...x.de,
	imx@...ts.linux.dev, Peng Fan <peng.fan@....com>,
	linux-kernel@...r.kernel.org, kernel@...gutronix.de,
	festevam@...il.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] soc: imx8m: Add remove function

On 24-12-06, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@....com>
> 
> Unregister the cpufreq device and soc device in remove path, otherwise
> there will be warning when do removing test:
> sysfs: cannot create duplicate filename '/devices/platform/imx-cpufreq-dt'
> CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.13.0-rc1-next-20241204
> Hardware name: NXP i.MX8MPlus EVK board (DT)
> 
> Fixes: 9cc832d37799 ("soc: imx8m: Probe the SoC driver as platform driver")
> Signed-off-by: Peng Fan <peng.fan@....com>
> ---
>  drivers/soc/imx/soc-imx8m.c | 32 +++++++++++++++++++++++++++-----
>  1 file changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/soc/imx/soc-imx8m.c b/drivers/soc/imx/soc-imx8m.c
> index 8ac7658e3d52..8c368947d1e5 100644
> --- a/drivers/soc/imx/soc-imx8m.c
> +++ b/drivers/soc/imx/soc-imx8m.c
> @@ -33,6 +33,11 @@ struct imx8_soc_data {
>  	int (*soc_revision)(u32 *socrev, u64 *socuid);
>  };
>  
> +struct imx8m_soc_priv {
> +	struct soc_device *soc_dev;
> +	struct platform_device *cpufreq_dev;
> +};
> +
>  #ifdef CONFIG_HAVE_ARM_SMCCC
>  static u32 imx8mq_soc_revision_from_atf(void)
>  {
> @@ -198,7 +203,7 @@ static int imx8m_soc_probe(struct platform_device *pdev)
>  	const struct imx8_soc_data *data;
>  	struct device *dev = &pdev->dev;
>  	const struct of_device_id *id;
> -	struct soc_device *soc_dev;
> +	struct imx8m_soc_priv *priv;
>  	u32 soc_rev = 0;
>  	u64 soc_uid = 0;
>  	int ret;
> @@ -207,6 +212,10 @@ static int imx8m_soc_probe(struct platform_device *pdev)
>  	if (!soc_dev_attr)
>  		return -ENOMEM;
>  
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
>  	soc_dev_attr->family = "Freescale i.MX";
>  
>  	ret = of_property_read_string(of_root, "model", &soc_dev_attr->machine);
> @@ -235,21 +244,34 @@ static int imx8m_soc_probe(struct platform_device *pdev)
>  	if (!soc_dev_attr->serial_number)
>  		return -ENOMEM;
>  
> -	soc_dev = soc_device_register(soc_dev_attr);
> -	if (IS_ERR(soc_dev))
> -		return PTR_ERR(soc_dev);
> +	priv->soc_dev = soc_device_register(soc_dev_attr);
> +	if (IS_ERR(priv->soc_dev))
> +		return PTR_ERR(priv->soc_dev);
>  
>  	pr_info("SoC: %s revision %s\n", soc_dev_attr->soc_id,
>  		soc_dev_attr->revision);
>  
>  	if (IS_ENABLED(CONFIG_ARM_IMX_CPUFREQ_DT))
> -		platform_device_register_simple("imx-cpufreq-dt", -1, NULL, 0);
> +		priv->cpufreq_dev = platform_device_register_simple("imx-cpufreq-dt", -1, NULL, 0);

If CONFIG_ARM_IMX_CPUFREQ_DT is enabled, I asusme that
platform_device_register_simple() shouldn't fail else it will be an
error, right? Therefore I would like to add the 'if(!IS_ERR())' check
here instead of the remove function.

> +
> +	platform_set_drvdata(pdev, priv);
>  
>  	return 0;
>  }
>  
> +static void imx8m_soc_remove(struct platform_device *pdev)
> +{
> +	struct imx8m_soc_priv *priv = platform_get_drvdata(pdev);
> +
> +	if (!IS_ERR(priv->cpufreq_dev))

With the above shifted, we only need to:
	if (priv->cpufreq_dev)

Regards,
  Marco


> +		platform_device_unregister(priv->cpufreq_dev);
> +
> +	soc_device_unregister(priv->soc_dev);
> +}
> +
>  static struct platform_driver imx8m_soc_driver = {
>  	.probe = imx8m_soc_probe,
> +	.remove	= imx8m_soc_remove,
>  	.driver = {
>  		.name = "imx8m-soc",
>  	},
> -- 
> 2.37.1
> 
> 
>