Re: [PATCH] usb: typec: fusb302: Call fusb302_debugfs_init earlier

[Chunfeng Yun <chunfeng.yun@mediatek.com>]

On Tue, 2019-08-13 at 13:52 +0300, Heikki Krogerus wrote:
> Hi Hans,
> 
> On Tue, Aug 13, 2019 at 12:15:24PM +0200, Hans de Goede wrote:
> > tcpm_register_port() will call some of the fusb302 code's callbacks
> > wich in turn will call fusb302_log(). So we need to call
> > fusb302_debugfs_init() before we call tcpm_register_port().
<...>
> > 
> > Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> > ---
> >  drivers/usb/typec/tcpm/fusb302.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> > index ccfc7e91e7a3..04c76b9d0065 100644
> > --- a/drivers/usb/typec/tcpm/fusb302.c
> > +++ b/drivers/usb/typec/tcpm/fusb302.c
> > @@ -1759,6 +1759,7 @@ static int fusb302_probe(struct i2c_client *client,
> >  	INIT_WORK(&chip->irq_work, fusb302_irq_work);
> >  	INIT_DELAYED_WORK(&chip->bc_lvl_handler, fusb302_bc_lvl_handler_work);
> >  	init_tcpc_dev(&chip->tcpc_dev);
> > +	fusb302_debugfs_init(chip);
> >  
> >  	if (client->irq) {
> >  		chip->gpio_int_n_irq = client->irq;
> > @@ -1784,7 +1785,6 @@ static int fusb302_probe(struct i2c_client *client,
> >  		goto tcpm_unregister_port;
> >  	}
> >  	enable_irq_wake(chip->gpio_int_n_irq);
> > -	fusb302_debugfs_init(chip);
> >  	i2c_set_clientdata(client, chip);
> 
> That leaves the rootdir variable pointing to something again for
> example if a failure happens (like -EPROBE_AGAIN) during probe (the
> "fusb302" directory is removed, but the rootdir static variable still
> points to something).
> 
> Let's just create that rootdir directory during driver init. I don't
> really understand why should we only create it when/if the first
> instance of fusb302 is registered. I think something like this would
> work:
> 
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index c524088246ee..7a950a6e5f0d 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -212,9 +212,6 @@ static struct dentry *rootdir;
>  static void fusb302_debugfs_init(struct fusb302_chip *chip)
>  {
>         mutex_init(&chip->logbuffer_lock);
> -       if (!rootdir)
> -               rootdir = debugfs_create_dir("fusb302", NULL);
> -
>         chip->dentry = debugfs_create_file(dev_name(chip->dev),
>                                            S_IFREG | 0444, rootdir,
>                                            chip, &fusb302_debug_fops);
> @@ -223,7 +220,6 @@ static void fusb302_debugfs_init(struct fusb302_chip *chip)
>  static void fusb302_debugfs_exit(struct fusb302_chip *chip)
>  {
>         debugfs_remove(chip->dentry);
> -       debugfs_remove(rootdir);
>  }
>  
>  #else
> @@ -1863,7 +1859,24 @@ static struct i2c_driver fusb302_driver = {
>         .remove = fusb302_remove,
>         .id_table = fusb302_i2c_device_id,
>  };
> -module_i2c_driver(fusb302_driver);
> +
> +static int __init fusb302_init(void)
> +{
> +       rootdir = debugfs_create_dir("fusb302", NULL);
> +       if (IS_ERR(rootdir))
> +               return PTR_ERR(rootdir);
This doesn't support multi-instance?

> +
> +       return i2c_add_driver(&fusb302_driver);
> +}
> +
> +static void __exit fusb302_exit(void)
> +{
> +       i2c_del_driver(&fusb302_driver);
> +       debugfs_remove(rootdir);
> +}
> +
> +module_init(fusb302_init);
> +module_exit(fusb302_exit);
>  
>  MODULE_AUTHOR("Yueyao Zhu <yueyao.zhu@gmail.com>");
>  MODULE_DESCRIPTION("Fairchild FUSB302 Type-C Chip Driver");
> 
> 
> If it's OK, could you include that into this patch?
> 
> thanks,
>