linux-kernel - Re: [PATCH v3 8/9] iio: amplifiers: ad8366: consume enable gpio

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Message-ID: <aYKtd_83eiJZ7hsR@smile.fi.intel.com>
Date: Wed, 4 Feb 2026 04:22:47 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: rodrigo.alencar@...log.com
Cc: linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org,
	Michael Hennerich <Michael.Hennerich@...log.com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Jonathan Cameron <jic23@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Andy Shevchenko <andy@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>
Subject: Re: [PATCH v3 8/9] iio: amplifiers: ad8366: consume enable gpio

On Tue, Feb 03, 2026 at 11:24:14AM +0000, Rodrigo Alencar via B4 Relay wrote:

> Some parts may consume enable GPIO to enable serial mode
> (HMC1119's and HMC792A P/S pin) or powerup the device
> (e.g. ADA4961's PWUP pin). Also, add a comment explaining
> that even though chips like HMC271A has a reset gpio, this
> driver previously considered the reset pin for parts that
> don't actually have a reset gpio, so it might have been
> used to enable/power the device.

...

> +	/*
> +	 * Previously, this driver considered the reset gpio for some devices

GPIO

> +	 * that don't actually have a reset pin, which could have been wired
> +	 * up to the enable pin instead, so some users might be relying on this
> +	 * to turn the chip on rather than reset it.
> +	 */
>  	reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset", GPIOD_OUT_HIGH);
>  	if (IS_ERR(reset_gpio))
>  		return dev_err_probe(&spi->dev, PTR_ERR(reset_gpio),
>  				     "Failed to get reset GPIO\n");

Yeah, this needs to be addressed somewhere in drivers/gpio/gpiolib-of.c.
Because OUT_HIGH for the reset doesn't sound right if the polarity is active high.

> +	enable_gpio = devm_gpiod_get_optional(&spi->dev, "enable", GPIOD_OUT_HIGH);
> +	if (IS_ERR(enable_gpio))
> +		return dev_err_probe(&spi->dev, PTR_ERR(enable_gpio),
> +				     "Failed to get enable GPIO\n");

-- 
With Best Regards,
Andy Shevchenko