Re: [PATCH 2/5] soundwire: sysfs: cleanup the logic for creating the dp0 sysfs attributes

[Greg Kroah-Hartman]

On Fri, Jul 29, 2022 at 09:46:26AM -0500, Pierre-Louis Bossart wrote:
> 
> 
> On 7/29/22 08:50, Greg Kroah-Hartman wrote:
> > There's no need to special-case the dp0 sysfs attributes, the
> > is_visible() callback in the attribute group can handle that for us, so
> > add that and add it to the attribute group list making the logic simpler
> > overall.
> > 
> > This is a step on the way to moving all of the sysfs attribute handling
> > into the default driver core attribute group logic so that the soundwire
> > core does not have to do any of it manually.
> > 
> > Cc: Vinod Koul <vkoul@xxxxxxxxxx>
> > Cc: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
> > Cc: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> > Cc: Sanyog Kale <sanyog.r.kale@xxxxxxxxx>
> > Cc: alsa-devel@xxxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> >  drivers/soundwire/sysfs_slave.c | 18 ++++++++++++------
> >  1 file changed, 12 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/soundwire/sysfs_slave.c b/drivers/soundwire/sysfs_slave.c
> > index 83e3f6cc3250..3723333a5c2b 100644
> > --- a/drivers/soundwire/sysfs_slave.c
> > +++ b/drivers/soundwire/sysfs_slave.c
> > @@ -174,6 +174,16 @@ static ssize_t words_show(struct device *dev,
> >  }
> >  static DEVICE_ATTR_RO(words);
> >  
> > +static umode_t dp0_is_visible(struct kobject *kobj, struct attribute *attr,
> > +			      int n)
> > +{
> > +	struct sdw_slave *slave = dev_to_sdw_dev(kobj_to_dev(kobj));
> > +
> > +	if (slave->prop.dp0_prop)
> > +		return attr->mode;
> > +	return 0;
> > +}
> 
> This changes the results slightly by creating an empty 'dp0' directory
> with no attributes inside.
> 
> Before:
> 
> [root@fedora ~]# cd /sys/bus/soundwire/devices/sdw:3:025d:0714:01
> [root@fedora sdw:3:025d:0714:01]# ls dp0
> ls: cannot access 'dp0': No such file or directory
> 
> After:
> [root@fedora sdw:3:025d:0714:01]# ls dp0

That should be fine, tools should just be looking for the attributes,
not the existance of a directory, right?

thanks,

greg k-h