From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Rob Herring <robh+dt@kernel.org>
Cc: "Benjamin Gaignard" <benjamin.gaignard@st.com>,
"Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Bastien Nocera" <hadess@hadess.net>,
"Frank Rowand" <frowand.list@gmail.com>,
"Marco Felsch" <m.felsch@pengutronix.de>,
"Guido Günther" <agx@sigxcpu.org>,
"Yannick Fertre" <yannick.fertre@st.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Linux Input" <linux-input@vger.kernel.org>,
DTML <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-stm32@st-md-mailman.stormreply.com,
"Mark Brown" <broonie@kernel.org>
Subject: Re: [PATCH 0/5] Add of_ functions for device_link_add()
Date: Thu, 25 Apr 2019 12:24:46 -0700 [thread overview]
Message-ID: <CAKdAkRTUsJ4TU7BrSNXCKiQGZnArao9o_qk7i0xSzYJ1SGU14A@mail.gmail.com> (raw)
In-Reply-To: <CAL_JsqJp9f3Sv08igSyR38Z5eXnAYWMNY29U5qEGLp=r2YReRw@mail.gmail.com>
On Thu, Apr 25, 2019 at 11:08 AM Rob Herring <robh+dt@kernel.org> wrote:
>
> On Wed, Apr 24, 2019 at 5:19 AM Benjamin Gaignard
> <benjamin.gaignard@st.com> wrote:
> >
> > It could happen that we need to control suspend/resume ordering between
> > devices without obvious consumer/supplier link. For example when touchscreens
> > and DSI panels share the same reset line, in this case we need to be sure
> > of pm_runtime operations ordering between those two devices to correctly
> > perform reset.
> > DSI panel and touchscreen aren't sharing any heriachical relationship (unlike
> > I2C client and I2C bus or regulator client and regulator provider) so we need
> > to describe this in device-tree.
>
> Needing to know which touchscreen is attached to a panel could be
> important to describe if you have multiple displays.
>
> Doesn't the reset subsystem already have some support for shared
> resets? Seems like it could provide clients with struct device or
> device_node ptrs to other devices sharing a reset.
>
> >
> > This series introduce of_device_links_{add,remove} and devm_of_device_links_add()
> > helpers to find and parse 'links-add' property in a device-tree node.
>
> Going to document that property somewhere? :)
>
> I think this is too generic and coupled to Linux. It doesn't have any
> information as to what is the dependency or connection nor what the
> direction of the dependency is.
>
> I'm not convinced we need to solve this generically vs. defining
> something for this specific example.
I am pretty sure there will be more drivers needing complex
dependencies. Doesn't ACPI allow defining relationship between devices
that goes beyond the tree structure?
Thanks.
--
Dmitry
next prev parent reply other threads:[~2019-04-25 19:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 10:19 [PATCH 0/5] Add of_ functions for device_link_add() Benjamin Gaignard
2019-04-24 10:19 ` [PATCH 1/5] of/device: Add of_ functions for device_link_{add,remove} Benjamin Gaignard
[not found] ` <d038f078-08dc-41ff-edc2-12f37d88a8a3@intel.com>
2019-04-24 13:39 ` Benjamin GAIGNARD
2019-04-24 10:19 ` [PATCH 2/5] Input: edt-ft5x06: Document links-add property Benjamin Gaignard
2019-04-24 10:19 ` [PATCH 3/5] input: edt-ft5x06 - Call devm_of_device_links_add() to create links Benjamin Gaignard
2019-04-24 22:52 ` Dmitry Torokhov
2019-04-25 7:22 ` Benjamin GAIGNARD
2019-04-24 10:19 ` [PATCH 4/5] Input: goodix: Document links-add property Benjamin Gaignard
2019-04-24 10:19 ` [PATCH 5/5] input: goodix - Call devm_of_device_links_add() to create links Benjamin Gaignard
2019-04-25 18:07 ` [PATCH 0/5] Add of_ functions for device_link_add() Rob Herring
2019-04-25 19:24 ` Dmitry Torokhov [this message]
2019-04-25 23:02 ` Rob Herring
2019-04-26 8:36 ` Benjamin GAIGNARD
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