linux-kernel - Re: [PATCH v1 6/8] iio: dac: ds4424: clear outputs on probe

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Message-ID: <aW6CDxVzO_NWGHSh@smile.fi.intel.com>
Date: Mon, 19 Jan 2026 21:12:15 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Oleksij Rempel <o.rempel@...gutronix.de>
Cc: Jonathan Cameron <jic23@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, kernel@...gutronix.de,
	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
	devicetree@...r.kernel.org, Andy Shevchenko <andy@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	David Jander <david@...tonic.nl>
Subject: Re: [PATCH v1 6/8] iio: dac: ds4424: clear outputs on probe

On Mon, Jan 19, 2026 at 07:24:22PM +0100, Oleksij Rempel wrote:
> The DS44xx devices have no reset pin or reset bit, so output registers
> may retain preconfigured values across reboot or warm reset.
> 
> Also, the driver suspend/resume path restores from data->raw. When the
> device is first probed, data->raw is zero-initialized and may not match
> the actual hardware state. A later suspend/resume can therefore change an
> output from a preconfigured non-zero value to 0 mA.
> 
> Initialize all channels to 0 output current during probe to ensure a
> deterministic baseline and consistent suspend/resume behavior.

...

> +static int ds4424_init(struct iio_dev *indio_dev)
> +{
> +	int i, ret;

Why is 'i' signed?

> +
> +	/* Set all channels to 0 current. */
> +	for (i = 0; i < indio_dev->num_channels; i++) {

	for (unsigned int i = ...) {

> +		ret = ds4424_set_value(indio_dev, 0, &indio_dev->channels[i]);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}

-- 
With Best Regards,
Andy Shevchenko