From: andy.shevchenko@gmail.com
To: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: sudeep.holla@arm.com, cristian.marussi@arm.com,
robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
conor+dt@kernel.org, linus.walleij@linaro.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 0/5] gpio: add pinctrl based generic gpio driver
Date: Fri, 20 Oct 2023 00:27:58 +0300 [thread overview]
Message-ID: <ZTGfXsLc_Z6yj_HB@surfacebook.localdomain> (raw)
In-Reply-To: <20231005025843.508689-1-takahiro.akashi@linaro.org>
Thu, Oct 05, 2023 at 11:58:38AM +0900, AKASHI Takahiro kirjoitti:
> This is a revised version of my previous RFC[1]. Although I modified
> the commits to make them look SCMI-independent, they are still posted
> as RFC because I have never tested them on real hardware.
>
> (background)
> I'm currently working on implementing SCMI pinctrl/gpio drivers
> on U-Boot[2]. Although the pinctrl driver for the kernel[3] was submitted
> by EPAM, it doesn't contain the gpio driver and I believe that we should
> discuss a couple of points on the kernel side to finalize my design for
> U-Boot.
>
> So this RFC is intended for reviews, especially to raise some issues.
>
> 1) how to obtain a value on an input pin
> All the existing gpio drivers are set to obtain a value on an input
> pin by accessing the hardware directly. In SCMI case, however, this is
> just impossible in its nature and must be supported via a protocol
> using "Input-value" configuration type. (See the spec[4], table-23.)
>
> The current pinconf framework is missing the feature (the pinconf
> parameter and a helper function). See patch#1, #2 and #3.
>
> Please note that there is an issue around the pin configuration in
> EPAM's current pinctrl driver as I commented[5].
>
> 2) DT bindings
> I would like to propose a generic binding for pinctrl based gpio driver.
> This allows a "consumer" driver to handle gpio pins like as other
> normal gpio controllers support. (patch#5)
>
> 3) generic GPIO driver
> Based on (2), I tried to prototype a generic driver in patch#4.
> Thanks to a set of existing pinctrl_gpio helper functions, except (1),
> It seems that the driver can be implemented not relying on pin controller
> specific code, at least for SCMI pinctrl.
>
> I will appreciate any comments.
Any comment here: I'm listed as a designated reviewer of GPIO patches, why am I
not Cc'ed on this? I definitely have some comments against the code (no DT,
though). Please, use (up-to-date) MAINTAINERS in your v3.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2023-10-19 21:29 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
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 ` andy.shevchenko [this message]
2023-10-20 0:21 ` [RFC v2 0/5] gpio: add " AKASHI Takahiro
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