Re: [PATCH 1/3] usb: typec: tcpm: Use usb_debug_root as root for our debugfs entry

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Thu, Aug 15, 2019 at 09:18:13PM +0200, Hans de Goede wrote:
> Use usb_debug_root as root for our debugfs entry instead of creating our
> own subdirectory under the debugfs root.
> 
> Another patch in this series will make the same change to the fusb302
> driver, which also uses dev_name() (on the same device) for the debugfs
> entry name. So we also prefix dev_name() with "tcpm-" here to avoid a
> name conflict.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/tcpm/tcpm.c | 17 +++++------------
>  1 file changed, 5 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 15abe1d9958f..5241d17c3399 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -19,6 +19,7 @@
>  #include <linux/seq_file.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
> +#include <linux/usb.h>
>  #include <linux/usb/pd.h>
>  #include <linux/usb/pd_ado.h>
>  #include <linux/usb/pd_bdo.h>
> @@ -571,17 +572,13 @@ static int tcpm_debug_show(struct seq_file *s, void *v)
>  }
>  DEFINE_SHOW_ATTRIBUTE(tcpm_debug);
>  
> -static struct dentry *rootdir;
> -
>  static void tcpm_debugfs_init(struct tcpm_port *port)
>  {
> -	mutex_init(&port->logbuffer_lock);
> -	/* /sys/kernel/debug/tcpm/usbcX */
> -	if (!rootdir)
> -		rootdir = debugfs_create_dir("tcpm", NULL);
> +	char name[NAME_MAX];
>  
> -	port->dentry = debugfs_create_file(dev_name(port->dev),
> -					   S_IFREG | 0444, rootdir,
> +	mutex_init(&port->logbuffer_lock);
> +	snprintf(name, NAME_MAX, "tcpm-%s", dev_name(port->dev));
> +	port->dentry = debugfs_create_file(name, S_IFREG | 0444, usb_debug_root,
>  					   port, &tcpm_debug_fops);
>  }
>  
> @@ -597,10 +594,6 @@ static void tcpm_debugfs_exit(struct tcpm_port *port)
>  	mutex_unlock(&port->logbuffer_lock);
>  
>  	debugfs_remove(port->dentry);
> -	if (list_empty(&rootdir->d_subdirs)) {
> -		debugfs_remove(rootdir);
> -		rootdir = NULL;
> -	}
>  }

I guess one option here as well would be to still group the entries
under the "tcpm" directry, but just place that under the
usb_debug_root directory.

thanks,

-- 
heikki