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Date: Wed, 19 Feb 2020 23:47:52 -0800
From: Randy Dunlap <rdunlap@...radead.org>
To: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
mazziesaccount@...il.com
Cc: Sebastian Reichel <sre@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"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: [RFC PATCH v3 3/8] drivers: base: add linear ranges helpers
Hi,
Here are some kernel-doc comments for you:
On 2/19/20 11:35 PM, Matti Vaittinen wrote:
> ---
> drivers/base/Kconfig | 3 +
> drivers/base/Makefile | 1 +
> drivers/base/linear_ranges.c | 246 +++++++++++++++++++++++++++++++++++
> 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/linear_ranges.c b/drivers/base/linear_ranges.c
> new file mode 100644
> index 000000000000..5fa3b96bf2b8
> --- /dev/null
> +++ b/drivers/base/linear_ranges.c
> @@ -0,0 +1,246 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * linear_ranges.c -- helpers to map values in a linear range to range index
> + *
> + * Original idea borrowed from regulator framework
> + *
> + * It might be useful if we could support also inversely proportional ranges?
> + * Copyright 2020 ROHM Semiconductors
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/export.h>
> +#include <linux/kernel.h>
> +#include <linux/linear_range.h>
> +
> +/**
> + * linear_range_values_in_range - return the amount of values in a range
> + *
> + * @r: pointer to linear range where values are counted
> + *
> + * Compute the amount of values in range pointed by @r. Note, values can
> + * be all equal - range with selectors 0,...,2 with step 0 still contains
> + * 3 values even though they are all equal.
> + *
> + * Returns the amount of values in range pointed by @r
* Return: ...
> + */
> +
> +/**
> + * linear_range_values_in_range_array - return the amount of values in ranges
> + *
> + * @r: pointer to array of linear ranges where values are counted
> + * @ranges: amount of ranges we include in computation.
> + *
> + * Compute the amount of values in ranges pointed by @r. Note, values can
> + * be all equal - range with selectors 0,...,2 with step 0 still contains
> + * 3 values even though they are all equal.
> + *
> + * Returns the amount of values in first @ranges ranges pointed by @r
* Return: ...
> + */
> +
> +/**
> + * linear_range_get_max_value - return the largest value in a range
> + *
> + * @r: pointer to linear range where value is looked from
> + *
> + * Returns the largest value in the given range
ditto.
> + */
> +
> +/**
> + * linear_range_get_value - fetch a value from given range
> + *
> + * @r: pointer to linear range where value is looked from
> + * @selector: selector for which the value is searched
> + * @val: address where found value is updated
> + *
> + * Search given ranges for value which matches given selector.
> + *
> + * Returns 0 on success, -EINVAL given selector is not found from any of the
ditto.
> + * ranges.
> + */
> +
> +/**
> + * linear_range_get_value_array - fetch a value from array of ranges
> + *
> + * @r: pointer to array of linear ranges where value is looked from
> + * @ranges: amount of ranges in an array
> + * @selector: selector for which the value is searched
> + * @val: address where found value is updated
> + *
> + * Search through an array of ranges for value which matches given selector.
> + *
> + * Returns 0 on success, -EINVAL given selector is not found from any of the
same, again.
> + * ranges.
> + */
> +
> +/**
> + * linear_range_get_selector_low - return linear range selector for value
> + *
> + * @r: pointer to linear range where selector is looked from
> + * @val: value for which the selcetor is searched
selector
> + * @selector: address where found selector value is updated
> + * @found: flag to indicate that given value was in the range
> + *
> + * Return selector which which range value is closest match for given
* Return:
> + * input value. Value is matching if it is equal or smaller than given
> + * value. If given value is in the range, then @found is set true.
> + *
> + * Returns 0 on success, -EINVAL if range is invalid or does not contain
> + * value smaller or equal to given value
> + */
> +int linear_range_get_selector_low(const struct linear_range *r,
> + unsigned int val, unsigned int *selector,
> + bool *found)
> +{
> + *found = false;
> +
> + if (r->min > val)
> + return -EINVAL;
> +
> + if (linear_range_get_max_value(r) >= val)
> + *found = true;
> +
> + if (!r->step)
> + *selector = r->min_sel;
> + else
> + *selector = (val - r->min) / r->step + r->min_sel;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(linear_range_get_selector_low);
> +
> +/**
> + * linear_range_get_selector_low_array - return linear range selector for value
> + *
> + * @r: pointer to array of linear ranges where selector is looked from
> + * @ranges: amount of ranges to scan from array
> + * @val: value for which the selcetor is searched
selector
> + * @selector: address where found selector value is updated
> + * @found: flag to indicate that given value was in the range
> + *
> + * Return Scan array of ranges for selector which which range value matches
drop "Return" ?
> + * given input value. Value is matching if it is equal or smaller than given
> + * value. If given value is found to be in a range scannins is stopped and
scanning
> + * @found is set true. If a range with values smaller than given value is found
> + * but the range max is being smaller than given value, then the ranges
> + * biggest selector is updated to @selector but scanning ranges is continued
> + * and @found is set to false.
> + *
> + * Returns 0 on success, -EINVAL if range array is invalid or does not contain
* Return:
> + * range with a value smaller or equal to given value
> + */
> +
> +/**
> + * linear_range_get_selector_high - return linear range selector for value
> + *
> + * @r: pointer to linear range where selector is looked from
> + * @val: value for which the selcetor is searched
selector
> + * @selector: address where found selector value is updated
> + * @found: flag to indicate that given value was in the range
> + *
> + * Return selector which which range value is closest match for given
> + * input value. Value is matching if it is equal or higher than given
> + * value. If given value is in the range, then @found is set true.
> + *
> + * Returns 0 on success, -EINVAL if range is invalid or does not contain
* Return:
> + * value greater or equal to given value
> + */
cheers.
--
~Randy
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