From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
linux-input@vger.kernel.org, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [RFC/PATCH 2/5] device property: introduce notion of subnodes for legacy boards
Date: Fri, 21 Sep 2018 16:31:19 -0700 [thread overview]
Message-ID: <20180921233119.GA44099@dtor-ws> (raw)
In-Reply-To: <20180920135348.GF11965@kuha.fi.intel.com>
Hi Heikki,
On Thu, Sep 20, 2018 at 04:53:48PM +0300, Heikki Krogerus wrote:
> Hi Dmitry,
>
> On Mon, Sep 17, 2018 at 11:16:00AM -0700, Dmitry Torokhov wrote:
> > +/**
> > + * device_add_child_properties - Add a collection of properties to a device object.
> > + * @dev: Device to add properties to.
>
> In case you didn't notice my comment for this, you are missing @parent
> here.
>
> But why do you need both the parent and the dev?
I could go by parent only and fetch dev from parent.
>
> > + * @properties: Collection of properties to add.
> > + *
> > + * Associate a collection of device properties represented by @properties as a
> > + * child of given @parent firmware node. The function takes a copy of
> > + * @properties.
> > + */
> > +struct fwnode_handle *
> > +device_add_child_properties(struct device *dev,
> > + struct fwnode_handle *parent,
> > + const struct property_entry *properties)
> > +{
> > + struct property_set *p;
> > + struct property_set *parent_pset;
> > +
> > + if (!properties)
> > + return ERR_PTR(-EINVAL);
> > +
> > + parent_pset = to_pset_node(parent);
>
> For this function, the parent will in practice have to be
> dev_fwnode(dev), so I don't think you need @parent at all, no?
>
> There is something wrong here..
Yes, I expect majority of the calls will use dev_fwnode(dev) as parent,
but nobody stops you from doing:
device_add_properties(dev, props);
c1 = device_add_child_properties(dev, dev_fwnode(dev), cp1);
c2 = device_add_child_properties(dev, c1, cp2);
c3 = device_add_child_properties(dev, c2, cp3);
...
>
> > + if (!parent_pset)
> > + return ERR_PTR(-EINVAL);
> > +
> > + p = pset_create_set(properties);
> > + if (IS_ERR(p))
> > + return ERR_CAST(p);
> > +
> > + p->dev = dev;
>
> That looks wrong.
>
> I'm guessing the assumption here is that the child nodes will never be
> assigned to their own devices, but you can't do that. It will limit
> the use of the child nodes to a very small number of cases, possibly
> only to gpios.
If I need to assign a node to a device I'll use device_add_properties()
API. device_add_child_properties() is for nodes living "below" the
device.
All nodes (the primary/secondary and children) would point to the owning
device, just for convenience.
>
> I think that has to be fixed. It should not be a big deal. Just expect
> the child nodes to be removed separately, and add ref counting to the
> struct property_set handling.
Why do we need to remove them separately and what do we need refcounting
for?
>
> > + p->parent = parent_pset;
> > + list_add_tail(&p->child_node, &parent_pset->children);
> > +
> > + return &p->fwnode;
> > +}
> > +EXPORT_SYMBOL_GPL(device_add_child_properties);
>
> The child nodes will change the purpose of the build-in property
> support. Originally the goal was just to support adding of build-in
> device properties to real firmware nodes, but things have changed
> quite a bit from that. These child nodes are purely tied to the
> build-in device property support, so we should be talking about adding
> pset type child nodes to pset type parent nodes in the API:
> fwnode_pset_add_child_node(), or something like that.
OK, I can change device_add_child_properties() to
fwnode_pset_add_child_node() if Rafael would prefer this name.
Thanks.
--
Dmitry
next prev parent reply other threads:[~2018-09-21 23:31 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-17 18:15 [RFC/PATCH 0/5] Support children for legacy device properties Dmitry Torokhov
2018-09-17 18:15 ` [RFC/PATCH 1/5] device property: split generic properties and property sets Dmitry Torokhov
2018-09-17 18:16 ` [RFC/PATCH 2/5] device property: introduce notion of subnodes for legacy boards Dmitry Torokhov
2018-09-19 15:10 ` Heikki Krogerus
2018-09-19 17:13 ` Dmitry Torokhov
2018-09-20 10:16 ` Heikki Krogerus
2018-09-21 23:33 ` Dmitry Torokhov
2018-09-24 7:29 ` Heikki Krogerus
2018-09-20 13:53 ` Heikki Krogerus
2018-09-21 15:36 ` Linus Walleij
2018-09-24 10:20 ` Heikki Krogerus
2018-09-21 23:31 ` Dmitry Torokhov [this message]
2018-09-24 13:20 ` Heikki Krogerus
2018-09-24 18:45 ` Dmitry Torokhov
2018-09-25 12:19 ` Heikki Krogerus
2018-10-05 21:47 ` Dmitry Torokhov
2018-10-11 8:18 ` Heikki Krogerus
2018-09-17 18:16 ` [RFC/PATCH 3/5] device property: export property_set structure Dmitry Torokhov
2018-09-17 18:16 ` [RFC/PATCH 4/5] gpiolib: add support for fetching descriptors from static properties Dmitry Torokhov
2018-09-18 9:02 ` Mika Westerberg
2018-09-18 17:04 ` Dmitry Torokhov
2018-09-19 8:33 ` Mika Westerberg
2018-09-17 18:16 ` [RFC/PATCH 5/5] RFC: ARM: simone: Hacked in keys Dmitry Torokhov
2018-09-18 4:23 ` [RFC/PATCH 0/5] Support children for legacy device properties Andy Shevchenko
2018-09-18 20:05 ` Rafael J. Wysocki
2018-09-19 19:55 ` Linus Walleij
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