From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Raag Jadav <raag.jadav@intel.com>,
linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Mika Westerberg <mika.westerberg@linux.intel.com>
Subject: Re: [PATCH v1 1/1] pinctrl: tangier: Move default strength assignment to a switch-case
Date: Thu, 2 Nov 2023 14:34:29 +0200 [thread overview]
Message-ID: <ZUOXVSij9497HrBR@smile.fi.intel.com> (raw)
In-Reply-To: <CACRpkdb3wLAZfU+_E0r5Rr_HD-bdFpf7K6bMD6dqiK1Ryv7NAQ@mail.gmail.com>
On Thu, Nov 02, 2023 at 08:36:11AM +0100, Linus Walleij wrote:
> On Mon, Oct 30, 2023 at 4:54 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
(...)
> > + case 1: /* Set default strength value in case none is given */
>
> So where does this 1 come from in the end? That's the piece I
> am missing in this explanation. Somewhere, someone decided
> to pass 1 to indicate "pull to default resistance".
>
> Is it coming from ACPI firmware?
No, it's pure Linux kernel decision.
gpio_set_bias() is who made that. That's why it needs to be chosen on global
level.
We may even document somewhere that arguments let's say up to 10 do not make
any sense in real life, as even for 1.2 v it will give 120 mA current on a single
pin. Yet, theoretically that's possible for discrete industrial GPIOs, so we
can choose "very big number" if such case appears in the future. I don't want
to change 1 to something else right now as it may break things.
> for default pull" should be added to the constant definition in the
> code.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2023-11-02 12:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 15:53 [PATCH v1 1/1] pinctrl: tangier: Move default strength assignment to a switch-case Andy Shevchenko
2023-10-30 21:14 ` Raag Jadav
2023-10-31 10:22 ` Andy Shevchenko
2023-10-31 13:57 ` Raag Jadav
2023-11-01 6:35 ` Mika Westerberg
2023-11-01 9:34 ` Andy Shevchenko
2023-11-01 10:44 ` Mika Westerberg
2023-11-02 7:36 ` Linus Walleij
2023-11-02 12:34 ` Andy Shevchenko [this message]
2023-11-02 12:37 ` Andy Shevchenko
2023-11-02 12:56 ` Linus Walleij
2023-11-13 11:53 ` Andy Shevchenko
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