From: AKASHI Takahiro <takahiro.akashi@linaro.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <robh@kernel.org>,
sudeep.holla@arm.com, cristian.marussi@arm.com,
krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
Oleksii_Moisieiev@epam.com, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-gpio@vger.kernel.org
Subject: Re: [RFC v2 5/5] dt-bindings: gpio: Add bindings for pinctrl based generic gpio driver
Date: Tue, 17 Oct 2023 11:32:11 +0900 [thread overview]
Message-ID: <ZS3yK/f12Mxw9rXe@octopus> (raw)
In-Reply-To: <CACRpkdYD6pkccYoy90AfzV3KT7oYkBPD2_4ZW-AXzT1eUVpchA@mail.gmail.com>
Hi Linus,
On Thu, Oct 12, 2023 at 09:25:20AM +0200, Linus Walleij wrote:
> On Tue, Oct 10, 2023 at 7:25???AM AKASHI Takahiro
> <takahiro.akashi@linaro.org> wrote:
>
> > > We can probably mandate that this has to be inside a pin controller
> > > since it is a first.
> >
> > Yeah, my U-Boot implementation tentatively supports both (inside and
> > outside pin controller). But it is not a user's choice, but we should
> > decide which way to go.
>
> OK I have decided we are going to put it inside the pin control node,
> as a subnode. (I don't expect anyone to object.)
While I'm still thinking of how I can modify my current implementation
to fit into 'inside' syntax, there are a couple of concerns:
1) invoke gpiochip_add_data() at probe function
Probably we no longer need "compatible" property, but instead we need to
call gpiochip_add_data() explicitly in SCMI pin controller's probe
as follows:
scmi_pinctrl_probe()
...
devm_pinctrl_register_and_init(dev, ..., pctrldev);
pinctrl_enable(pctrldev);
device_for_each_child_node(dev, fwnode)
if (fwnode contains "gpio-controller") {
/* what pin_control_gpio_probe() does */
gc->get_direction = ...;
...
devm_gpiochip_data_add(dev, gc, ...);
}
2) gpio-by-pinctrl.c
While this file is SCMI-independent now, due to a change at (1),
it would be better to move the whole content inside SCMI pin controller
driver (because there is no other user for now).
3) Then, pin-control-gpio.yaml may also be put into SCMI binding
(i.e. firmware/arm,scmi.yaml). Can we leave the gpio binding outside?
4) phandle in "gpio-ranges" property
(As you mentioned)
The first element in a tuple of "gpio-ranges" is a phandle to a pin
controller node. Now that the gpio node is a sub node of pin controller,
the phandle is trivial. But there is no easier way to represent it
than using an explicit label:
(My U-Boot implementation does this.)
scmi {
...
scmi_pinctrl: protocol@19 {
...
gpio {
gpio-controller;
...
gpio-ranges = <&scmi_pinctrl ... >;
}
}
}
I tried:
gpio-ranges = <0 ...>; // dtc passed, but '0' might be illegal by spec.
gpio-ranges = <(-1) ...>; // dtc passed, but ...
gpio-ranges = <&{..} ...>; // dtc error because it's not a full path.
Do you have any other idea? Otherwise, I will modify my RFC
with the changes above.
-Takahiro Akashi
> It makes everything easier and clearer for users I think.
>
> Yours,
> Linus Walleij
next prev parent reply other threads:[~2023-10-17 2:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 2:58 [RFC v2 0/5] gpio: add pinctrl based generic gpio driver AKASHI Takahiro
2023-10-05 2:58 ` [RFC v2 1/5] pinctrl: define PIN_CONFIG_INPUT AKASHI Takahiro
2023-10-10 11:53 ` Linus Walleij
2023-10-05 2:58 ` [RFC v2 2/5] pinctrl: always export pin_config_get_for_pin() AKASHI Takahiro
2023-10-10 11:54 ` Linus Walleij
2023-10-05 2:58 ` [RFC v2 3/5] pinctrl: add pinctrl_gpio_get_config() AKASHI Takahiro
2023-10-05 2:58 ` [RFC v2 4/5] gpio: add pinctrl based generic gpio driver AKASHI Takahiro
2023-10-10 12:00 ` Linus Walleij
2023-10-12 1:08 ` AKASHI Takahiro
2023-10-05 2:58 ` [RFC v2 5/5] dt-bindings: gpio: Add bindings for " AKASHI Takahiro
2023-10-05 19:48 ` Krzysztof Kozlowski
2023-10-12 1:15 ` AKASHI Takahiro
2023-10-12 7:27 ` Krzysztof Kozlowski
2023-10-06 13:18 ` Rob Herring
2023-10-06 13:23 ` Rob Herring
2023-10-09 7:49 ` Linus Walleij
2023-10-09 9:08 ` Cristian Marussi
2023-10-09 13:13 ` Linus Walleij
2023-10-09 15:08 ` Cristian Marussi
2023-10-10 5:14 ` AKASHI Takahiro
2023-10-10 5:25 ` AKASHI Takahiro
2023-10-12 7:25 ` Linus Walleij
2023-10-17 2:32 ` AKASHI Takahiro [this message]
2023-10-23 8:12 ` Linus Walleij
2023-10-24 7:12 ` AKASHI Takahiro
2023-10-24 9:40 ` Linus Walleij
2023-10-24 10:55 ` Cristian Marussi
2023-10-24 13:01 ` Linus Walleij
2023-10-24 11:09 ` AKASHI Takahiro
2023-10-24 13:12 ` Linus Walleij
2023-10-24 13:42 ` AKASHI Takahiro
2023-11-05 22:15 ` Linus Walleij
2023-10-19 21:27 ` [RFC v2 0/5] gpio: add " andy.shevchenko
2023-10-20 0:21 ` AKASHI Takahiro
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