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From: "Enrico Weigelt, metux IT consult" <info@metux.net>
To: Linus Walleij <linus.walleij@linaro.org>,
	"Enrico Weigelt, metux IT consult" <info@metux.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.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>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [RFC PATCH 07/12] gpio: amd-fch: add oftree probing support
Date: Thu, 11 Mar 2021 11:17:15 +0100	[thread overview]
Message-ID: <acae5f9a-1cc8-46e1-2b3b-c806679ef062@metux.net> (raw)
In-Reply-To: <CACRpkdb5R+VQrv0QuKa+EYmAMkodRpyv4fV1QCWQ+vcEyd0sZQ@mail.gmail.com>

On 01.03.21 15:51, Linus Walleij wrote:

Hi,

> I don't know what the idea is with this but register are not normally defined
> in the DTS files. The registers are determined from the compatible value.

The idea is basically replacing the pdata struct by oftree node.
(subsequent patches in this queue use this by doing the board setup via
compiled-in dtb, instead of the currently hardcoded tables).

On these SoCs, the gpio setup is a little bit more complex than just
having a fixed range of registers (one per pin): the actual meaning
depends und Soc model and board type - some regs aren't even gpios.
(I'm still in progress of RE'ing the bios blob, to find out more,
eg. pinmux setups, etc). Writing to the wrong regs can cause weird
effects (actually not even sure whether it could lead to damage)

In essence: only a specific subset of the register range can be used
for GPIOs - the others shouldn't ever be touched. And this specific
subset is soc/board specific.


--mtx

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Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@metux.net -- +49-151-27565287

  reply	other threads:[~2021-03-11 10:18 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 [this message]
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
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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