Date:   Wed, 10 Nov 2021 18:36:54 +0100
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Alistair Francis <alistair23@gmail.com>
Cc:     Alistair Francis <alistair@alistair23.me>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        devicetree <devicetree@vger.kernel.org>,
        linux-input <linux-input@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Mylene Josserand <mylene.josserand@free-electrons.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Henrik Rydberg <rydberg@bitmath.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH v2 2/4] Documentation: DT: bindings: input: Add
 documentation for cyttsp5
Message-ID: <20211110183654.61328998@kemnade.info>
In-Reply-To: <CAKmqyKNx00ecsAyOjtLk8i6r75WD0uw=nd=fd9z44yBuau+Vdw@mail.gmail.com>
References: <20211103114830.62711-1-alistair@alistair23.me>
        <20211103114830.62711-3-alistair@alistair23.me>
        <20211105152154.20f5cbd1@aktux>
        <CAKmqyKNx00ecsAyOjtLk8i6r75WD0uw=nd=fd9z44yBuau+Vdw@mail.gmail.com>
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On Wed, 10 Nov 2021 22:59:50 +1000
Alistair Francis <alistair23@gmail.com> wrote:

[...]
> >  
> > > +            reset-gpios = <&pio 7 1 GPIO_ACTIVE_HIGH>;  
> >
> > hmm, if the reset gpio at the chip is active low (I guess it is) that
> > would indicate an inverter between SoC and gpio. So a nonstandard setup
> > as an example, probably not a good idea.  
> 
> It seems to be common for the cypress,tt2100, as the original
> documentation and the rM2 both do this. Does the Kobo not do this?
> 

You have a kind of double inversion here, so things are automagically fixed.
IMHO to describe it correctly would be to set GPIO_ACTIVE_LOW here
and in the driver

	/* Reset the gpio to be in a reset state */
	ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(ts->reset_gpio)) {
		rc = PTR_ERR(ts->reset_gpio);
		dev_err(dev, "Failed to request reset gpio, error %d\n", rc);
		return rc;
	}
	gpiod_set_value(ts->reset_gpio, 0);

That is the way how other active-low reset lines are handled.

Regards,
Andreas