linux-kernel - Re: [PATCH v4 0/6] Add support for the LTM8054 voltage regulator

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Message-ID: <23111366.EfDdHjke4D@fw-rgant>
Date: Mon, 24 Nov 2025 16:13:26 +0100
From: Romain Gantois <romain.gantois@...tlin.com>
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 Andy Shevchenko <andriy.shevchenko@...el.com>
Subject: Re: [PATCH v4 0/6] Add support for the LTM8054 voltage regulator

Hello Guenter,

On Monday, 24 November 2025 15:57:41 CET Guenter Roeck wrote:
> On 11/24/25 06:48, Romain Gantois wrote:
> > Hello everyone,
> > 
> > This is version four of my series which adds initial support of the Linear
> > Technology LTM8054 voltage regulator. The driver supports a fixed voltage
> > and a tunable output current limit using a DAC-controlled pin.
> > 
> > I'd say that the most unusual part of this series is the usage of the IIO
> > consumer API in a regulator driver. I think this makes sense here, since
> > the regulator driver has to access a DAC to read/set the output current
> > limit.
> 
> I don't think that is a valid reason. Literally every driver measuring
> voltages or current uses a DAC to do it. How else would one convert an
> analog value into a digital value ?

Sorry, I don't quite understand your remark. To integrate this voltage 
regulator component into the Linux regulator abstraction, I'm providing a 
current limit control function. To provide such a function, the voltage level 
on a pin has to be controlled. AFAIK, the kernel abstraction used to set 
precise voltages on lines is an IO channel.

Do you think that using the IIO consumer API is not correct here? What other 
method do you think I should use?

Thanks,

-- 
Romain Gantois, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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