[PATCH] soc: imx8m: Add remove function

[Peng Fan]

> Subject: Re: [PATCH] soc: imx8m: Add remove function
> 
> On 24-12-06, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan at nxp.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 at nxp.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.

You mean below?
dev = platform_device_register_simple("imx-cpufreq-dt", -1, NULL, 0);
if (!IS_ERR(dev))
   plat->cpufreq_dev = dev;
else
  pr_err("Failed to register imx-cpufreq-dt: %d\n", ERR_PTR(dev))?

But using !IS_ERR(plat->cpufreq_dev) in remove path looks
simpler.

Thanks,
Peng

> 
> > +
> > +	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
> >
> >
> >