Linux GPIO subsystem development
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From: Stefan Wahren <wahrenst@gmx.net>
To: Kent Gibson <warthog618@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Florian Fainelli <florian.fainelli@broadcom.com>,
	bcm-kernel-feedback-list@broadcom.com,
	Ray Jui <rjui@broadcom.com>,
	Scott Branden <sbranden@broadcom.com>,
	linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Bartosz Golaszewski <brgl@bgdev.pl>,
	Phil Elwell <phil@raspberrypi.com>
Subject: Re: [PATCH] pinctrl: bcm2835: Make pin freeing behavior configurable
Date: Thu, 2 May 2024 13:11:06 +0200	[thread overview]
Message-ID: <79627aeb-8151-430c-98f4-5689fd61413f@gmx.net> (raw)
In-Reply-To: <20240502110442.GA315256@rigel>

Hi Kent,

Am 02.05.24 um 13:04 schrieb Kent Gibson:
> On Thu, May 02, 2024 at 12:22:07PM +0200, Stefan Wahren wrote:
>> Am 19.04.24 um 22:40 schrieb Stefan Wahren:
>>> Until now after a bcm2835 pin was freed its pinmux was set to GPIO_IN.
>>> So in case it was configured as GPIO_OUT before the configured output
>>> level also get lost. As long as GPIO sysfs was used this wasn't
>>> actually a problem because the pins and their possible output level
>>> were kept by sysfs.
>>>
>>> Since more and more Raspberry Pi users start using libgpiod they are
>>> confused about this behavior. So make the pin freeing behavior of
>>> GPIO_OUT configurable via module parameter. In case
>>> pinctrl-bcm2835.strict_gpiod is set to 0, the output level is kept.
>>>
>>> This patch based on the downstream work of Phil Elwell.
>>>
>>> Link: https://github.com/raspberrypi/linux/pull/6117
>>> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
>>> ---
>>>    drivers/pinctrl/bcm/pinctrl-bcm2835.c | 20 ++++++++++++++++----
>>>    1 file changed, 16 insertions(+), 4 deletions(-)
>> Gentle ping ...
> I can't comment on the substance of the change as pinctrl is outside my
> wheelhouse, but the "strict_gpiod" name could be better.
> The point is to make GPIO outputs persist, right?
Yes, correct.
> The name should better reflect that.
Finding good and short names is hard, do you have a suggestion?

Thanks
>
> Cheers,
> Kent.
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


  reply	other threads:[~2024-05-02 11:11 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-19 20:40 [PATCH] pinctrl: bcm2835: Make pin freeing behavior configurable Stefan Wahren
2024-05-02 10:22 ` Stefan Wahren
2024-05-02 11:04   ` Kent Gibson
2024-05-02 11:11     ` Stefan Wahren [this message]
2024-05-02 11:15       ` Kent Gibson
2024-05-02 12:20         ` Stefan Wahren

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