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Subject: Re: [PATCH v6 3/4] of: overlay: add per overlay sysfs attributes
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From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
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Date: Wed, 21 Oct 2015 22:37:45 +0300
Cc: Frank Rowand <frowand.list@gmail.com>, Matt Porter <mporter@konsulko.com>,
        Koen Kooi <koen@dominion.thruhere.net>,
        Guenter Roeck <linux@roeck-us.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
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To: Rob Herring <robherring2@gmail.com>
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Hi Rob,

> On Oct 21, 2015, at 00:54 , Rob Herring <robherring2@gmail.com> wrote:
> 
> On Tue, Oct 20, 2015 at 4:11 PM, Pantelis Antoniou
> <pantelis.antoniou@konsulko.com> wrote:
>> Hi Rob,
>> 
>>> On Oct 21, 2015, at 00:04 , Rob Herring <robherring2@gmail.com> wrote:
>>> 
>>> On Tue, Oct 20, 2015 at 2:13 PM, Pantelis Antoniou
>>> <pantelis.antoniou@konsulko.com> wrote:
>>>> * A per overlay can_remove sysfs attribute that reports whether
>>>> the overlay can be removed or not due to another overlapping overlay.
>>>> 
>>>> * A target sysfs attribute listing the target of each fragment,
>>>> in a group named after the name of the fragment.
> 
> [...]
> 
>>>> @@ -255,6 +278,17 @@ err_fail:
>>>>       return -EINVAL;
>>>> }
>>>> 
>>>> +static ssize_t target_show(struct kobject *kobj,
>>>> +               struct fragment_attribute *fattr, char *buf)
>>>> +{
>>>> +       struct of_overlay_info *ovinfo = fattr->ovinfo;
>>>> +
>>>> +       return snprintf(buf, PAGE_SIZE, "%s\n",
>>>> +                       of_node_full_name(ovinfo->target));
>>> 
>>> This can be a link to the node itself, can't it?
>>> 
>> 
>> Yes. Do you want it like this?
> 
> Yes, hence the suggestion. Unless you see some reason why not.
> 

Nope, can’t be done. The sysfs API only allows linking one kobj to another.
The kobj is the overlay but the target is in the fragment attribute group.

Sorry, I really tried, but can’t be done without hacking in a new link sysfs API. 

> Rob

Regards

— Pantelis