Re: [PATCH v4 5/6] iio: dac: ad5504: strictly separate ACPI and DT probe paths

[Andy Shevchenko]

On Mon, Aug 17, 2026 at 05:11:14PM -0400, Taha Ed-Dafili wrote:
> Refactor the ad5504_probe() function to explicitly separate the ACPI
> and Device Tree execution paths. Previously, the driver relied on a
> fragile -ENODEV return value check from the regulator framework to
> bypass the voltage check on ACPI platforms.
> 
> Following modern IIO subsystem design patterns (such as those found in
> adc/ti-ads7950.c), fork the logic using ACPI_COMPANION(). On ACPI
> systems, where dedicated voltage regulators are typically omitted from
> the firmware description, bypass the regulator subsystem entirely and
> initialize the reference voltage to the hardware default 60V scale via
> a new macro AD5504_VA_MV_ACPI_DEFAULT.
> 
> For Device Tree platforms, treat the VCC regulator as mandatory and
> wrap the allocation in dev_err_probe() to cleanly handle potential
> deferrals and error propagation.

...

> +/*
> + * In case of ACPI, we use the 60 V as default voltage reference.
> + */
> +#define AD5504_VA_MV_ACPI_DEFAULT	(60 * MILLI)

Name it

#define AD5504_VA_ACPI_DEFAULT_mV	(60 * MILLI)

What does VA stand for?

...

> +	if (ACPI_COMPANION(dev)) {

It's better to use has_acpi_companion() or is_acpi_device_node().
I prefer to see the latter as that one unifies the style of checking
across the drivers and subsystems.

For that you will need to use dev_fwnode() from property.h and acpi.h
for the macro itself.

> +		st->vref_mv = AD5504_VA_MV_ACPI_DEFAULT;

...

> -	st->vref_mv = ret / 1000;
> +		st->vref_mv = ret / MILLI;

This should be  (MICRO / MILLI) instead of MILLI.

-- 
With Best Regards,
Andy Shevchenko