From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Enrico Weigelt, metux IT consult" <info@metux.net>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>,
Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>
Subject: Re: RFC: oftree based setup of composite board devices
Date: Wed, 10 Feb 2021 12:30:40 +0200 [thread overview]
Message-ID: <CAHp75VdNTenoE0AOmGfndqQ7SrxbuK+SvfFYn3W2GmqhkCSByQ@mail.gmail.com> (raw)
In-Reply-To: <20210208222203.22335-1-info@metux.net>
On Tue, Feb 9, 2021 at 12:25 AM Enrico Weigelt, metux IT consult
<info@metux.net> wrote:
>
> Hello folks,
>
> here's an RFC for using compiled-in dtb's for initializing board devices
> that can't be probed via bus'es or firmware.
>
> Use cases are boards with non-oftree firmware (ACPI, etc) where certain
> platform devices can't be directly enumerated via firmware. Traditionally
> we had to write board specific drivers that check for board identification
> (DMI strings, etc), then initialize the actual devices and their links
> (eg. gpio<->leds/buttons, ...). Often this can be expressed just by DT.
In ACPI we support DT compatible strings, and we support overlays for
a long time. Would it work for you?
> This patch queue does a bunch of preparations in oftree code, so we can
> support multiple fully independent DT's (not using DT overlays). And then
> adds a generic driver parses compiled-in fdt blobs, checks for mathing
> DMI strings and initializes the devices. As an example, the last patch
> adds an alternative implementation for the PC engines APU2/3/4 board
> family based on device tree.
Sounds weird, but let's see...
> The approach can be easily be extended to other kinds of composite devices,
> eg. PCI cards or USB dongles.
What do you mean? PCI and USB are self-enumerated. What's wrong with them?
> Yet some drawbacks of the current implementation:
>
> * individual FDT's can't be modularized yet (IMHO, we don't have DMI-based
> modprobing anyways)
What?! https://lwn.net/Articles/233385/
`git grep -n 'MODULE_DEVICE_TABLE(dmi'`
> * can't reconfigure or attach to devices outside the individual DT's
> (eg. probed by PCI, etc)
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-02-10 10:38 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-08 22:21 RFC: oftree based setup of composite board devices Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 01/12] of: base: improve error message in of_phandle_iterator_next() Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 02/12] of: base: introduce of_find_node_by_phandle_from() Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 03/12] of: base: record root node in interator and use it for phandle lookup Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 04/12] of: base: introduce of_match_string() Enrico Weigelt, metux IT consult
2021-02-08 23:52 ` Rob Herring
2021-02-08 22:21 ` [RFC PATCH 05/12] of: kobj: __of_attach_node_sysfs(): add optional basename parameter Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 06/12] of: kobj: introduce of_attach_tree_sysfs() Enrico Weigelt, metux IT consult
2021-02-08 22:21 ` [RFC PATCH 07/12] gpio: amd-fch: add oftree probing support Enrico Weigelt, metux IT consult
2021-02-11 9:57 ` Bartosz Golaszewski
2021-03-01 14:51 ` Linus Walleij
2021-03-11 10:17 ` Enrico Weigelt, metux IT consult
2021-03-11 10:42 ` Andy Shevchenko
2021-03-18 8:00 ` Enrico Weigelt, metux IT consult
2021-03-25 9:09 ` Linus Walleij
2021-02-08 22:21 ` [RFC PATCH 08/12] drivers: base: introduce bus_remove_device_by_name() Enrico Weigelt, metux IT consult
2021-02-08 22:22 ` [RFC PATCH 09/12] drivers: base: reintroduce find_bus() Enrico Weigelt, metux IT consult
2021-02-13 10:20 ` Greg KH
2021-02-23 20:13 ` Enrico Weigelt, metux IT consult
2021-02-24 8:00 ` Greg KH
2021-02-24 15:30 ` Enrico Weigelt, metux IT consult
2021-02-24 16:28 ` Greg KH
2021-02-08 22:22 ` [RFC PATCH 10/12] export bus_get() / bus_put() Enrico Weigelt, metux IT consult
2021-02-08 22:22 ` [RFC PATCH 11/12] platform/x86: skeleton for oftree based board device initialization Enrico Weigelt, metux IT consult
2021-02-10 10:32 ` Andy Shevchenko
2021-02-12 9:58 ` Linus Walleij
2021-02-12 11:54 ` Enrico Weigelt, metux IT consult
2021-02-15 1:18 ` Frank Rowand
2021-02-23 20:41 ` Enrico Weigelt, metux IT consult
2021-03-02 13:33 ` Linus Walleij
2021-02-08 22:22 ` [RFC PATCH 12/12] platform/x86/of: add support for PC Engines APU v2/3/4 boards Enrico Weigelt, metux IT consult
2021-02-09 0:06 ` Rob Herring
2021-02-11 13:15 ` Enrico Weigelt, metux IT consult
2021-03-01 14:55 ` Linus Walleij
2021-02-08 23:48 ` RFC: oftree based setup of composite board devices Rob Herring
2021-02-10 22:13 ` Enrico Weigelt, metux IT consult
2021-02-15 1:12 ` Frank Rowand
2021-02-15 15:35 ` Andy Shevchenko
2021-02-24 13:00 ` Enrico Weigelt, metux IT consult
2021-02-24 23:14 ` Frank Rowand
2021-03-05 18:29 ` Rob Herring
2021-02-10 10:30 ` Andy Shevchenko [this message]
2021-02-11 11:08 ` Enrico Weigelt, metux IT consult
2021-02-11 11:41 ` Andy Shevchenko
2021-02-11 17:01 ` Enrico Weigelt, metux IT consult
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