Re: [PATCH] base: soc: Handle custom soc information sysfs entries

[mnalajal]

On 2019-10-03 00:05, Greg KH wrote:
> On Wed, Oct 02, 2019 at 05:06:14PM -0700, Murali Nalajala wrote:
> > Soc framework exposed sysfs entries are not sufficient for some
> > of the h/w platforms. Currently there is no interface where soc
> > drivers can expose further information about their SoCs via soc
> > framework. This change address this limitation where clients can
> > pass their custom entries as attribute group and soc framework
> > would expose them as sysfs properties.
> >
> > Signed-off-by: Murali Nalajala <mnalajal@xxxxxxxxxxxxxx>
> > ---
> >  drivers/base/soc.c      | 26 ++++++++++++++++++--------
> >  include/linux/sys_soc.h |  1 +
> >  2 files changed, 19 insertions(+), 8 deletions(-)
>
> Can you change a soc driver to use this?  I don't think that this patch
> works because:
>
> > diff --git a/drivers/base/soc.c b/drivers/base/soc.c
> > index 7c0c5ca..ec70a58 100644
> > --- a/drivers/base/soc.c
> > +++ b/drivers/base/soc.c
> > @@ -15,6 +15,8 @@
> >  #include <linux/err.h>
> >  #include <linux/glob.h>
> >
> > +#define NUM_ATTR_GROUPS 3
> > +
> >  static DEFINE_IDA(soc_ida);
> >
> >  static ssize_t soc_info_get(struct device *dev,
> > @@ -104,11 +106,6 @@ static ssize_t soc_info_get(struct device *dev,
> >  	.is_visible = soc_attribute_mode,
> >  };
> >
> > -static const struct attribute_group *soc_attr_groups[] = {
> > -	&soc_attr_group,
> > -	NULL,
> > -};
> > -
> >  static void soc_release(struct device *dev)
> >  {
> >  	struct soc_device *soc_dev = container_of(dev, struct soc_device, 
> > dev);
> > @@ -121,6 +118,7 @@ static void soc_release(struct device *dev)
> >  struct soc_device *soc_device_register(struct soc_device_attribute 
> > *soc_dev_attr)
> >  {
> >  	struct soc_device *soc_dev;
> > +	const struct attribute_group **soc_attr_groups = NULL;
> >  	int ret;
> >
> >  	if (!soc_bus_type.p) {
> > @@ -136,10 +134,20 @@ struct soc_device *soc_device_register(struct 
> > soc_device_attribute *soc_dev_attr
> >  		goto out1;
> >  	}
> >
> > +	soc_attr_groups = kzalloc(sizeof(*soc_attr_groups) *
> > +						NUM_ATTR_GROUPS, GFP_KERNEL);
> > +	if (!soc_attr_groups) {
> > +		ret = -ENOMEM;
> > +		goto out2;
> > +	}
> > +	soc_attr_groups[0] = &soc_attr_group;
> > +	soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
> > +	soc_attr_groups[2] = NULL;
>
> You set this, but never do anything with it that I can see.  What am I
> missing?
no, since i am using the "soc_attr_groups" name as it here you do not 
see the assignment below.
It is something like this soc_dev->dev.groups = soc_attr_groups;
> > +
> >  	/* Fetch a unique (reclaimable) SOC ID. */
> >  	ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
> >  	if (ret < 0)
> > -		goto out2;
> > +		goto out3;
> >  	soc_dev->soc_dev_num = ret;
> >
> >  	soc_dev->attr = soc_dev_attr;
> > @@ -151,14 +159,16 @@ struct soc_device *soc_device_register(struct 
> > soc_device_attribute *soc_dev_attr
> >
> >  	ret = device_register(&soc_dev->dev);
> >  	if (ret)
> > -		goto out3;
> > +		goto out4;
> >
> >  	return soc_dev;
> >
> > -out3:
> > +out4:
> >  	ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
> >  	put_device(&soc_dev->dev);
> >  	soc_dev = NULL;
> > +out3:
> > +	kfree(soc_attr_groups);
> >  out2:
> >  	kfree(soc_dev);
> >  out1:
>
> You don't free it when the soc is removed?
agree, will fix it in my next patch.
> thanks,
>
> greg k-h
These changes are verified at my side on SM8250 with mode static 
compilation and module.