linux-kernel - Re: [PATCH v4 3/9] drivers: base: add linear ranges helpers

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Message-ID: <20200318130838.GB2769584@kroah.com>
Date:   Wed, 18 Mar 2020 14:08:38 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     mazziesaccount@...il.com, Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Markus Laine <markus.laine@...rohmeurope.com>,
        Mikko Mutanen <mikko.mutanen@...rohmeurope.com>
Subject: Re: [PATCH v4 3/9] drivers: base: add linear ranges helpers

On Tue, Feb 25, 2020 at 10:53:01AM +0200, Matti Vaittinen wrote:
> Many devices have control registers which control some measurable
> property. Often a register contains control field so that change in
> this field causes linear change in the controlled property. It is not
> a rare case that user wants to give 'meaningful' control values and
> driver needs to convert them to register field values. Even more
> often user wants to 'see' the currently set value - again in
> meaningful units - and driver needs to convert the values it reads
> from register to these meaningful units. Examples of this include:
> 
> - regulators, voltage/current configurations
> - power, voltage/current configurations
> - clk(?) NCOs
> 
> and maybe others I can't think of right now.
> 
> Provide a linear_range helper which can do conversion from user value
> to register value 'selector'.
> 
> The idea here is stolen from regulator framework and patches refactoring
> the regulator helpers to use this are following.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
> ---
> 
> Changes since rfc-v3:
>   - Kerneldoc fixes
>   - Corrected commit message typo meaningfull => meaningful
> 
>  drivers/base/Kconfig         |   3 +
>  drivers/base/Makefile        |   1 +
>  drivers/base/linear_ranges.c | 246 +++++++++++++++++++++++++++++++++++

Why in drivers/base/ ?

Why not in lib/ ?

>  include/linux/linear_range.h |  48 +++++++
>  4 files changed, 298 insertions(+)
>  create mode 100644 drivers/base/linear_ranges.c
>  create mode 100644 include/linux/linear_range.h
> 
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 5f0bc74d2409..636b6fa8e499 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -209,4 +209,7 @@ config GENERIC_ARCH_TOPOLOGY
>  	  appropriate scaling, sysfs interface for reading capacity values at
>  	  runtime.
>  
> +config LINEAR_RANGES
> +	tristate

No help text at all???

> +EXPORT_SYMBOL(linear_range_values_in_range);

EXPORT_SYMBOL_GPL() for all of these?  I have to ask...

> @@ -0,0 +1,48 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */

Are you sure about the "or later"?  Again, I have to ask.

> +/* Copyright (C) 2020 ROHM Semiconductors */
> +
> +#ifndef LINEAR_RANGE_H
> +#define LINEAR_RANGE_H
> +
> +#include <linux/types.h>

Why is this needed?

thanks,

greg k-h